The Florida Land Trust
The Florida Land Trust is an amazing device which offers numerous benefits to property owners. The two reasons it is not used by every investor are that few know much about it and those who know about it do not know where to obtain trust services at a reasonable cost.
Trusts in general go back many hundreds of years and today they offer even more benefits than they did when they were invented. The Florida land trust is a statutory form of the "Illinois-type" land trust which has been used for over a hundred years.
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Over twenty other benefits of using a land trust are listed in the book, Land Trusts in Florida, which you should read if you are planning to use a land trust. Some of the most popular benefits are, keeping the sales price secret, keeping liens and judgments off the property, avoiding a spouse's forced share, and avoiding litigation.
The beneficiary of your trust can be you individually, a corporation, a limited liability company, a partnership or any other legal entity. If you are the beneficiary individually, you can name any other person or entity to immediately become successor beneficiary upon your death. If your company is the beneficiary, you can name a successor in your company papers.
Besides a beneficiary, you can have a director. For example, you can set up a trust in which your children are the beneficiaries (paying the taxes on income) but you are the director. As director you would make all the decisions regarding the property. If you loan someone money you can have them put their property in a land trust and make you the director. Then you could control the property until you were paid in full.
IN THE DISTRICT COURT OF APPEAL OF THE STATE OF FLORIDA
FOURTH DISTRICT JULY TERM 2001
PINECREST LAKES, INC.; and
VILLAS AT PINECREST LAKES
LIMITED PARTNERSHIP,
Appellants,
v.
KAREN SHIDEL,
Appellee.
CASE NO. 4D99-2641
Opinion filed September 26, 2001
Appeal from the Circuit Court for the
Nineteenth Judicial Circuit, Martin County; Larry
Schack, Judge; L.T. Case No. 96-126 CA.
Jack J. Aiello and Ernest A. Cox, III, of
Gunster, Yoakley, Valdes-Fauli & Stewart, P.A.,
West Palm Beach, for appellants.
Richard Grosso, General Counsel, Environmental
& Land Use Law Center, Fort Lauderdale, for
appellee.
Stephen H. Grimes and Lawrence E. Sellers, Jr.
of Holland & Knight, LLP., Tallahassee, for Amici
Curiae, National Association of Home Builders,
Florida Home Builders Association, Florida
Association of Realtors, and Association of Florida
Community Developers, Inc.
Michael L. Rosen, Tallahassee, for Amicus
Curiae, Florida Legal Foundation, Inc.
Terrell K. Arline, Legal Director, Tallahassee,
Thomas G. Pelham, Kenneth J. Goldberg and
Douglas W. Ackerman, Tallahassee, for Amici
Curiae, The Florida Chapter of the American
Planning Association, and 1000 Friends of Florida,
Inc.
C
ORRECTED OPINIONFARMER, J.
The ultimate issue raised in this case is
unprecedented in Florida. The question is whether
a trial court has the authority to order the complete
demolition and removal of several multi-story
buildings because the buildings are inconsistent
with the County’s comprehensive land use plan.
We conclude that the court is so empowered and
affirm the decision under review.
Some twenty years ago, a developer
1 purchaseda 500-acre parcel of land in Martin County and set
out to develop it in phases. Development there is
governed by the Martin County Comprehensive
Plan (the Comprehensive Plan).
2 Phase One ofthe property was designated under the
Comprehensive Plan as “Residential Estate,”
meaning single-family homes on individual lots
with a maximum density of 2 units per acre
(UPA). The Comprehensive Plan provides that
“[w]here single family structures comprise the
dominant structure type within these areas, new
development of undeveloped abutting lands shall
1Originally the developer was Pinecrest Lakes, Inc.,
the entity which planned and built Phases One through
Ten. In 1997, when we reversed the first appeal in this
case for a trial de novo, the corporation transferred title
to Phase Ten to a limited partnership known as The
Villas at Pinecrest Lakes. The trial court substituted the
limited partnership for the corporation as the developer.
Consequently, when we use the term “developer” in
this opinion, we refer either to the corporation or the
limited partnership or both as the context requires.
2
See § 163.3167(2), Fla. Stat. (2000) (“Each localgovernment shall prepare a comprehensive plan of the
type and in the manner set out in this act or shall
prepare amendments to its existing comprehensive plan
to conform it to the requirements of this part in the
manner set out in this part.”).
(2)
be required to include compatible structure types
of land immediately adjacent to existing single
family development.” [e.s.]
Phases One through Nine were developed as
single-family homes on individual lots in very low
densities.
The subject of this litigation, Phase Ten, is a 21-
acre parcel between Phase One and Jensen
Beach Boulevard, a divided highway designated
both as “major” and “arterial.” Phase Ten was
designated by the Comprehensive Plan as
“Medium Density Residential” with a maximum of
8 UPA. The developer sought approval of three
different site plans before finally erecting the
buildings that are the subject of this litigation. In
1988, the developer first sought approval for an
initial scheme of 3-story apartment buildings with
a density of just under 8 UPA. Karen Shidel,
since 1986 an owner of a single-family residence
in the adjoining area of Phase One, along with
other residents, opposed the project proposed by
the developer. This initial site plan for Phase Ten
was approved by the County but never acted
upon.
Five years later the developer changed the
proposed scheme to single family residences, and
the County Commission approved a revised site
plan for 29 single-family homes with a density of
1.37 UPA. Two years after that, however, the
developer again changed its mind and returned to
its original concept of multi-family structures. This
time, the developer sought to develop 136 units in
two-story buildings, with a density of 6.5 UPA.
The County’s growth management staff
recommended that the County Commission
approve this second revised site plan for Phase
Ten. Following a hearing at which a number of
people objected to the proposal, including Shidel,
the County Commission approved the revision and
issued a Development Order
3 for Phase Tenpermitting the construction of 19 two-story
buildings.
Claiming statutory authority, Shidel and another
Phase One homeowner, one Charles Brooks,
along with the Homeowners Associations for
Phases One through Nine, then filed a verified
complaint with the Martin County Commission
challenging the consistency of the Development
Order with the Comprehensive Plan, requesting
rescission of the Development Order.
4 Inresponse to the verified complaint, after a hearing
the County Commission confirmed its previous
decision to issue the Development Order.
Shidel and Brooks then filed a civil action in the
Circuit Court against Martin County under the
same statutory authority.
5 They alleged that the3
See § 163.3164(7) and (8), Fla. Stat. (2000)(“‘Development permit’ includes any building permit,
zoning permit, subdivision approval, rezoning,
certification, special exception, variance, or any other
official action of local government having the effect of
permitting the development of land.… ‘Development
order’ means any order granting, denying, or granting
with conditions an application for a development
permit.”).
4
See § 163.3215(4), Fla. Stat. (2000) (“As a conditionprecedent to the institution of an action pursuant to
this section, the complaining party shall first file a
verified complaint with the local government whose
actions are complained of, setting forth the facts upon
which the complaint is based and the relief sought by
the complaining party. The verified complaint shall be
filed no later than 30 days after the alleged inconsistent
action has been taken. The local government receiving
the complaint shall respond within 30 days after receipt
of the complaint. Thereafter, the complaining party may
institute the action authorized in this section. However,
the action shall be instituted no later than 30 days after
the expiration of the 30-day period which the local
government has to take appropriate action.”).
5
See § 163.3215(1), Fla. Stat. (1995) (“Any aggrievedor adversely affected party may maintain an action for
injunctive or other relief against any local government
to prevent such local government from taking any
action on a development order…which materially alters
the use or density or intensity of use on a particular
piece of property that is not consistent with the
comprehensive plan adopted under this part.”).
(3)
Development Order was inconsistent with the
Comprehensive Plan. The developer intervened.
Shidel and Brooks argued that their statutory
challenge was a de novo proceeding in which the
court should decide in the first instance whether
the Development Order was consistent with the
Comprehensive Plan. Martin County and the
developer argued that the proceeding was in the
nature of appellate review in which the County’s
determination was entitled to deference and the
court should consider only whether there was
substantial competent evidence supporting the
Development Order. Basing its decision solely on
a review of the record created before the County
Commission, the trial court found that the
Development Order was consistent with the
Comprehensive Plan and entered final judgment in
favor of the developer.
At that point, the developer took stock of its
position. It had prevailed before the County
Commission and—at least initially—in the trial
court. Technically, however, its approval for the
project was not final. Developer considered
whether to proceed to construct the buildings or
instead await appellate review of the trial court’s
decision. Ultimately the developer decided to
commence construction, notwithstanding the
pendency of an appeal. Accordingly, it applied for
and received building permits for construction of
Buildings 8, 9, 10, 11 and 12, and started on each
of those buildings while the case was under
consideration in court.
6 When construction wasjust beginning, Shidel and Brooks sent written
notice to the developer of their intention, should
they prove successful in court, to seek demolition
and removal of any construction undertaken while
judicial consideration of the consistency issue was
pending.
Appellate review did not produce the outcome
for which the developer had hoped. In 1997 we
reversed the trial court’s decision that the
County’s consistency determination complied with
the Comprehensive Plan. Poulos v. Martin
County, 700 So. 2d 163 (Fla. 4th DCA 1997).
Specifically, we concluded that section 163.3215
required de novo consideration in the trial court on
the consistency issue. Our opinion explained:
“if section 163.3215 was intended to provide for
the circuit court to conduct an appellate review
by certiorari, then the statutory language
permitting the filing of the action up to 90 days
after the granting of the development order is in
conflict with the 30 day deadline outlined under
the Florida Rules of Appellate Procedure.”
700 So. 2d at 165. We further adopted an analysis
by Judge Wentworth as to the meaning of section
163.3215:
“the…language in the statute…provides only for
a suit or action clearly contemplating an
evidentiary hearing before the court to
determine the consistency issue on its merits in
the light of the proceedings below but not
confined to the matters of record in such
proceedings.”
700 So. 2d at 166 (quoting from Gregory v. City
of Alachua, 553 So. 2d 206, 211 (Fla. 1st DCA
1989) (Wentworth, J., dissenting)). We remanded
the case for a trial de novo and for any
appropriate relief.
On remand, the trial judge
7 proceeded in twos tages: the first stage involved a determination
whether the Development Order was consistent
with the Comprehensive Plan; and the second
stage, which became necessary, addressed the
remedy. While the case was pending on remand,
developer continued with construction. The
County conducted final inspections of Building 11
and 12, issuing certificates of occupancy (CO),
and residents moved into the buildings. At the end
of the consistency phase, the trial court entered a
partial judgment finding that the Development
6We express no view on the propriety of Martin
County issuing building permits while the case was
pending in court.
7The original judge assigned to the case was rotated
into another division, so the case was assigned to a
new judge.
(4)
Order was not consistent with the Comprehensive
Plan. The trial de novo then proceeded to the
remedy.
At the conclusion of the remedy phase, the trial
court entered a Final Judgment. The court found
that the Comprehensive Plan established a
hierarchy of land uses, paying deferenc e to lower
density residential uses and providing protection to
those areas. The “tiering policy” required that, for
structures immediately adjacent to each other, any
new structures to be added to the area must be
both comparable and compatible to those already
built and occupied.
8 The court then foundsignificant differences between the northern tier of
Phase One and the adjacent southern tier of
Phase Ten. The structures in Phase One were
single level, single family residences, while the
structures in Phase Ten were two-story apartment
buildings with eight residential units. Therefore,
the court found, the 8-residential unit, two-story,
apartment buildings in Phase Ten were not
compatible or comparable types of dwelling units
with the single family, single level residences in
Phase One; nor were they of comparable density.
Consequently, the court determined, the
Development Order was inconsistent with the
Comprehensive Plan.
As regards the remedy, the Final Judgment
found no evidence indicating that either Brooks or
the Homeowners Association were damaged by
any diminution in value. The court found that the
Homeowners Association was not a person within
the meaning of section 163.3215(2) and therefore
had no standing to seek relief under section
163.3215. Accordingly, only plaintiff Shidel was
entitled to seek injunctive relief under section
163.3215.
In granting such relief, the court found that the
developer had acted in bad faith. Specifically, the
court found that the developer continued
construction during the pendency of the prior
appeal and continued to build and lease during the
trial—even after losing on the consistency issue.
The court found that the developer “acted at [its]
own peril in doing precisely what this lawsuit
sought to prevent and now [is] subject to the
power of the court to compel restoration of the
status prior to construction.” The relief awarded
was:
(1) the Court permanently enjoined Martin
County from taking any further action on the
subject Development Order for Phase Ten,
other than to rescind it;
(2) the Court permanently enjoined developer
and its successors in interest from any further
development of Phase Ten under the subject
Development Order; and
(3) the Court ordered developer to remove all
apartment buildings from Phase Ten either
through demolition or physic al relocation by a
date certain.
When the Final Judgment was entered, five of the
eight-unit buildings had been constructed in Phase
Ten (Buildings 8-12). Buildings 11 and 12 had
already received their CO’s, and fifteen of their
sixteen units were actually occupied. Building 10
was fully completed and was awaiting final
inspection as of the date the remedies stage of
trial began. Buildings 8 and 9 were 50% and 66%
completed, respectively, also as of that date.
Following the entry of Final Judgment, the
developer filed this timely appeal and moved for
a stay pending review.
9 The trial court granted a8“A project immediately adjacent to lands used or
designated for lower intensity use should be given
lesser density. (1) For that portion of said project
abutting the existing development or area of lesser
density, a density transition zone of comparable
density and compatible dwelling unit types shall be
established [e.s.] in the new project for a depth from the
shared property line that is equivalent to the depth of
the first tier of the adjoining development’s lower
density (i.e. the depth of the first block of single-family
lots).” Comprehensive Plan, § 4-5(A)(2)(b).
9Neither Charles Brooks nor Martin County has
appealed the final judgment, or filed a brief in this
appeal by Karen Shidel.
(5)
stay only as to the demolition order, allowing
lessees to continue in possession of those
apartments in Buildings 9-12 under actual lease
when the trial court entered final judgment, as well
as to those leases in Building 8 in existence as of
the date of filing of the notice of appeal. The
developer was prohibited, however, from entering
into any renewals of existing leases upon
expiration of the original term or any new leases
of any apartments. Upon review, we affirmed the
stay order. We now explain our decision on the
merits.
I. The Consistency Issue
Initially the developer argues that the trial court
erred in the consistency phase by failing to accord
any deference to the County Commission’s
interpretation of its own Comprehensive Plan
when the County approved the second revised site
plan and its multi-story, multi-family buildings.
Conceding that the proceedings are de novo and
that the Development Order is subject to “strict
scrutiny” under the Comprehensive Plan as to the
consistency issue, the developer nevertheless
argues that the courts must bow to the County’s
interpretation of its own Comprehensive Plan and
the application of its many elements to the site
plan. Developer argues that the statutes and
cases accord such deference to a local
government’s interpretation of its own
Comprehensive Plan and that it was reversible
error for the trial court in this case to fail to do so.
In partic ular, developer relies on Southwest
Ranches Homeowners Ass’n v. Broward
County, 502 So. 2d 931 (Fla. 4th DCA 1987), and
B.B. McCormick & Sons, Inc. v. City of
Jacksonville, 559 So. 2d 252 (Fla. 1st DCA
1990). According to developer, these cases
authorize the use of the highly deferential “fairly
debatable” standard of review—customary with
zoning decisions—to land use determinations such
as the issue of consistency in this case. We
disagree.
As we have already seen in this dispute, the
applicable statute provides that:
“[a]ny aggrieved or adversely affected party
may maintain an action for injunctive or other
relief against any local government to prevent
such local government from taking any action on
a development order…which materially alters
the use or density or intensity of use on a
particular piece of property that is not consistent
with the comprehensive plan….”
§ 163.3215(1), Fla. Stat. (2000). This statute
obviously creates an action for an injunction
against the enforcement of a development order,
rather than to carry out such an order. The
statute is aimed at development orders—which, by
their very nature, must have been approved by a
local government—so it is clear that the
Legislature did not mean that local governments or
developers would be the parties seeking injunctive
relief under this provision.
Moreover there is but one basis for issuing the
injunction: that the development order is not
consistent with the Comprehensive Plan to the
detriment of adjoining property owners. Hence
the issuance of an injunction under section
163.3215(1) necessarily requires the judge to
determine in the first instance whether a
development order is consistent with the
Comprehensive Plan. When a statute authorizes a
citizen to bring an action to enjoin official conduct
that is made improper by the statute, and that
same statute necessitates a determination by the
judge in the action as to whether the official’s
conduct was improper under the statute, as a
general matter the requirement for a determination
of the propriety of the official action should not be
understood as requiring the court to defer to the
official whose conduct is being judged. While the
Legislature could nevertheless possibly have some
reason to require some deference to the officials
whose conduct was thus put in issue, we would
certainly expect to see such a requirement of
deference spelled out in the statute with
unmistakable clarity. Here it is not a question of
any lack of clarity; the statute is utterly silent on
the notion of deference. It is thus apparent that
(6)
the structure and text of the statute do not
impliedly involve any deference to the decision of
the county officials. So we necessarily presume
none was intended.
10Section 163.3194 requires that all development
conform to the approved Comprehensive Plan, and
that development orders be consistent with that
Plan.
11 The statute is framed as a rule, acommand to cities and counties that they must
comply with their own Comprehensive Plans after
they have been approved by the State. The
statute does not say that local governments shall
have some discretion as to whether a proposed
development should be consistent with the
Comprehensive Plan. Consistency with a
Comprehensive Plan is therefore not a
discretionary matter. When the Legislature wants
to give an agency discretion and then for the
courts to defer to such discretion, it knows how to
say that. Here it has not. We thus reject the
developer’s contention that the trial court erred in
failing to defer to the County’s interpretation of its
own comprehensive plan.
Before we proceed to assess the trial court’s
determination on the consistency issue, we pause
to consider the history of the land development
statutes. The State of Florida did not assert
meaningful formal control over the explosive and
unplanned development of land in this state until
the passage of the first growth management
statute, the Local Government Comprehensive
Planning Act of 1975. Chapter 75-257, Laws of
Fla. (the 1975 Act). The 1975 Act forced
counties and cities to adopt comprehensive plans,
but they were left to interpret such plans for
themselves, largely free from effective oversight
by the state. See, e.g., City of Jacksonville
Beach v. Grubbs, 461 So. 2d 160, 163 (Fla. 1st
DCA 1984) (determination of when to conform
more restrictive zoning ordinances with
Comprehensive Plan is legislative judgment to be
made by local governing body, subject only to
limited judicial review for patent arbitrariness).
The requirement of adopting a Comprehensive
Plan was, therefore, only a small step. Moreover
nothing in the legislation required local
governments to comply with their own
Comprehensive Plans or that all development be
consistent with the Plan.
By the early 1980’s it was widely recognized
10To illustrate the point, we draw an analogy. The
action by a county approving a development order
could fairly and logically be compared to the actions of
administrative agencies generally. Thus we might
contrast section 163.3215(1) with comparable provisions
of the Administrative Procedures Act. Section 120.68
generally grants parties in agency proceedings access
to a court after the agency has finally acted. Section
120.68(4), however, limits review to the record in
agency. There is no similar provision in section
163.3215. Moreover section 120.68(7) spells out in
precise detail exactly what the reviewing court can do.
Among its provisions is the following:
“The court shall remand a case to the agency for
further proceedings consistent with the court’s
decision or set aside agency action, as appropriate,
when it finds that … (b) The agency’s action
depends on any finding of fact that is not supported
by competent, substantial evidence in the record of
a hearing conducted pursuant to ss. 120.569 and
120.57; however, the court shall not substitute its
judgment for that of the agency as to the weight of
the evidence on any disputed finding of fact … (e)
the agency’s exercise of discretion was: 1. outside
the range of discretion delegated to the agency by
law; 2. inconsistent with agency rule; 3. inconsistent
with officially stated agency policy or a prior agency
practice, if deviation therefrom is not explained by the
agency; or 4. otherwise in violation of a
constitutional or statutory provision; but the court
shall not substitute its judgment for that of the
agency on an issue of discretion.” [e.s.]
§ 120.68(7), Fla. Stat. (2000). There is nothing even
remotely comparable in section 163.3215.
11
See § 163.3194(1)(a), Fla. Stat. (2000) (“After acomprehensive plan…has been adopted in conformity
with this act, all development undertaken by, and all
actions taken in regard to development orders by,
governmental agencies in regard to land covered by
such plan or element shall be consistent with such plan or element as adopted.”). [e.s.]
(7)
that the 1975 Act was proving ineffectual in
regulating Florida’s development. See Reid
Ewing, Florida’s Growth Management
Learning Curve, 19 V
A. ENVT’L. L. J. 375(2000). The lack of state control over
interpretation of the Comprehensive Plan was
often cited as a serious deficiency. As one such
criticism described the situation:
“[f]rustration grew at the state level as well.
Lacking the actual power to approve or
disapprove local planning decisions, state and
regional planners could not effectively
coordinate and oversee local planning and
regulation. Local governments changed their
plans ‘willy-nilly virtually every time a city
council or county commission met...’ ”
John M. DeGrove, State and Regional Planning
and Regulatory Activity: The Florida
Experience and Lessons for Other
Jurisdictions, C390 ALI– ABA 397, 428 (1994).
For another thing, the 1975 Act was criticized
for failing to give affected property owners and
citizen groups standing to challenge the land
development decisions of local governments on the
grounds that they were inconsistent with the
Comprehensive Plan. The standing issue was
considered in Citizens Growth Management
Coalition of West Palm Beach Inc. v. City of
West Palm Beach, 450 So. 2d 204 (Fla. 1984)
(CGMC). CGMC involved a challenge by a
citizens group to a local decision to allow the
construction of a large scale residential and
commercial complex. The court began by
referring to Renard v. Dade County, 261 So.2d
832 (Fla. 1972), holding that standing to challenge
local development decisions was limited to the
highly deferential “fairly debatable” standard.
Affected property owners in the vicinity of new
development had no standing to seek enforcement
of local comprehensive plans unless they could
“prove special damages different in kind from that
suffered by the community as a whole.” 261 So.
2d at 834. The CGMC court determined that the
1975 Act did not change these rules on standing.
450 So. 2d at 208. The court reasoned that
because the 1975 Act “did not specifically address
the question” of standing, the statute was not
meant to alter the common law standing
requirements set forth in Renard. 450 So. 2d at
206-07.
Again, to return to the criticism, this limitation on
standing to enforce local planning laws resulted in:
“a failure to conform development decisions to
the plan based upon the fact that citizens lacked
standing to challenge development orders for
lack of consistency with the comprehensive
plan.”
James C. Nicholas & Ruth L. Steiner, Growth
Management and Smart Growth in Florida, 35
W
AKE FOREST L. REV. 645, 657 (2000)(quotingDaniel W. O'Connell, Growth Management in
Florida: Will State and Local Governments Get
Their Acts Together?, F
LORIDA ENVT’L &U
RBAN ISSUES, 1-5 (June 1984)). If affectedproperty owners in the area of newly permitted
development could not challenge a project on the
grounds that it would be inconsistent with the
Comprehensive Plan, that eliminated the only real
check on local government compliance—a
challenge by those most directly affected by a
proposed development.
The growing pressure for a fundamental change
in the growth management law is reflected in the
following statement made just prior to the
Legislature’s adoption of the current law in 1985:
“In response to this lack of citizen standing, a
citizen initiative began last year and thousands of
signatures were collected around the state to
bring the standing issue to a referendum vote.
The petition specific ally calls for a referendum
on the issues of giving citizens a right in the state
constitution to environmental health and welfare
and providing them with legal standing to sue if
government at the local, regional, or state level
is not doing its job.
“That initiative fell just a few thousand
signatures short of the required number for
qualifying for a referendum in 1984. However,
(8)
the initiative is continuing, and I feel confident that
the issue will be brought to the voters of the state
in 1985 unless the legislature addresses the issue
more effectively than it did last year.”
Kathleen Shea Abrams, An Environmental Word,
1 J. L
AND USE & ENVT’L LAW 155, 159 (1985).Clearly the pressure from a “civically militant
electorate” was growing, and the elected
representatives took notice of it. The result was
the Growth Management Act of 1985. Chap. 85-
55, Laws of Fla. This is essentially the statute we
have today, parts of which have been cited in
preceding paragraphs.
12 Its most importantprovision for our purposes was section 163.3215,
the provision used by Shidel to bring this action
into court.
In Southwest Ranches, we observed that
section 163.3215 had liberalized standing
requirements and demonstrated “a clear legislative
policy in favor of the enforcement of
comprehensive plans by persons adversely
affected by local action.” 502 So. 2d at 935. In
Parker v. Leon County, 627 So. 2d 476, 480 (Fla.
1993), the court held that “the legislature enacted
section 163.3215 to ensure the standing for any
person who ‘will suffer an adverse effect to an
interest protected ... by the ... comprehensive
plan.’ ” 627 So. 2d at 479. The Parker court
quoted with approval the above passage from
Southwest Ranches. 627 So. 2d at 479. See also
Putnam County Envt’l Council, Inc. v. Board of
County Comm’rs of Putnam County, 757 So. 2d
590, 593 (Fla. 5th DCA 2000) (“That standard
changed, however, with the 1985 adoption of
section 163.3215, which liberalized the standing
requirements and ‘demonstrat[ed] a clear
legislative policy in favor of the enforcement of
comprehensive plans by persons adversely
affected by local action.’”). Thus, the criticism
described above certainly was of great influence
in the 1985 Legislature’s formulation of the new
standing provision. Affected citizens have been
given a significantly enhanced standing to
challenge the consistency of development
decisions with the Comprehensive Plan.
The Growth Management Act of 1985 was
discussed in what is now recognized as the most
significant land use decision by the supreme court
in the past decade, namely Board of County
Commissioners of Brevard County v. Snyder,
627 So. 2d 469 (Fla. 1993). Snyder involved a
parcel then zoned only for single family homes and
a proposed development of 5-6 units. The
proposal also necessarily required a change of
zoning. After substantial opposition, and in spite of
a favorable staff recommendation, the County
voted to deny the request without giving any
reasons. Certiorari was denied in the circuit court,
one judge dissenting. The Fifth District held that
rezoning actions entailing the application of a
general rule or policy to specific individuals,
interests, or activities are quasi-judicial in nature
and should be subjected to a stricter standard of
judicial review. The court found that the proposed
site plan was consistent with the Comprehensive
Plan, that there was no evidence supporting the
denial of any necessary rezoning, and that the
denial of the request without giving any reasons
was arbitrary and unreasonable.
After granting review, the supreme court was
first concerned with the level of review given by
the courts to such proceedings. The county took
the position that it had been faced with primarily a
legislative judgment because the landowner sought
rezoning. As the court noted:
“Both federal and state courts adopted a highly
deferential standard of judicial review early in
the history of local zoning. In Village of Euclid
v. Ambler Realty Co., 272 U.S. 365 (1926), the
United States Supreme Court held that ‘[i]f the
validity of the legislative classification for zoning
purposes be fairly debatable, the legislative
judgment must be allowed to control.’ This
Court expressly adopted the fairly debatable
principle in City of Miami Beach v. Ocean &
Inland Co., 147 Fla. 480, 3 So.2d 364 (1941).”
12
See supra notes 2, 3, 4 and 5 and accompanyingtext.
(9)
[c.o.]
627 So. 2d at 472. The court went on to note,
however, that this tolerant form of judicial review
had not proved satisfactory:
“Inhibited only by the loose judicial scrutiny
afforded by the fairly debatable rule, local zoning
systems developed in a markedly inconsistent
manner. Many land use experts and
practitioners have been critical of the local
zoning system. Richard Babcock deplored the
effect of ‘neighborhoodism’ and rank political
influence on the local decision-making process.
Richard F. Babcock, The Zoning Game (1966).
Mandelker and Tarlock recently stated that
‘zoning dec isions are too often ad hoc, sloppy
and self-serving decisions with well-defined
adverse consequences without off-setting
benefits.’ Daniel R. Mandelker and A. Dan
Tarlock, Shifting the Presumption of
Constitutionality in Land-Use Law, 24 U
RB.L
AW. 1, 2 (1992).”627 So. 2d at 472-73.
The court explained that in Florida the 1975 Act
“was substantially strengthened by the Growth
Management Act [of 1985].” 627 So. 2d at 473.
After analyzing various provisions of the Growth
Management Act of 1985, the court stated:
“We also agree with the court below that the
review is subject to strict scrutiny. In practical
effect, the review by strict scrutiny in zoning
cases appears to be the same as that given in
the review of other quasi-judicial decisions. See
Lee County v. Sunbelt Equities, II, Ltd.
Partnership, 619 So.2d 996 (Fla. 2d DCA1993)
(The term ‘strict scrutiny’ aris es from the
necessity of strict compliance with
comprehensive plan.). This term as used in the
review of land use decisions must be
distinguished from the type of strict scrutiny
review afforded in some constitutional cases.
Compare Snyder v. Board of County
Comm'rs, 595 So.2d 65, 75-76 (Fla. 5th
DCA1991) (land use), and Machado v.
Musgrove 519 So.2d 629, 632 (Fla. 3d
DCA1987), review denied, 529 So.2d 693
(Fla.1988), and review denied, 529 So.2d 694
(Fla.1988) (land use), with In re Estate of
Greenberg, 390 So.2d 40, 42-43 (Fla.1980)
(general discussion of strict scrutiny review in
context of fundamental rights), appeal
dismissed, 450 U.S. 961 (1981), Florida High
Sch. Activities Ass'n v. Thomas, 434 So.2d 306
(Fla.1983) (equal protection), and Department
of Revenue v. Magazine Publishers of
America, Inc., 604 So.2d 459 (Fla.1992) (First
Amendment).” [e.s.]
627 So. 2d at 475.
In the foregoing quotation the supreme court
drew a distinction between the use of strict
scrutiny in land use cases and its use in other
contexts. The court approved the analyses of the
Fifth District in Snyder and the Third District in
Machado v. Musgrove, 519 So. 2d 629, 632 (Fla.
3d DCA 1987), review denied, 529 So. 2d 693
(Fla.), review denied, 529 So. 2d 694 (Fla. 1988),
regarding land use decisions. These courts
explained that strict scrutiny of local government
development orders is necessary to insure that the
local governments comply with the duty imposed
by section 163.3194 to make decis ions consistent
with the Comprehensive Plan. In discussing the
difference between a developer aggrieved by a
land use decision of local government and an
affected property owner in the vicinity aggrieved
by a proposed new development, the Snyder court
emphasized that section 163.3215 “provides a
remedy for third parties to challenge the
consistency of development orders.” 627 So. 2d
at 475.
As one pair of writers put it, “Snyder changed
the rules of the game for local government land
use approvals.” John W. Howell & David J.
Russ, Planning vs. Zoning: Snyder Decision
Changes Rezoning Standards, F
LA. B.J., May1994, at 16. And another pair noted:
“The easygoing ‘fairly debatable’ test for sitespecific
rezonings was abandoned and the ‘strict
scrutiny’ standard was adopted for the review
of development orders under a county’s
(10)
comprehensive master plan.”
Lucia A. Dougherty & Elliot H. Scherker, Rights,
Remedies, and Ratiocination: Toward a
Cohesive Approach to Appellate Review of
Land Use Orders After Board of County
Commissioners v. Snyder, 24 S
TET. L. REV. 311,312 (1995). In light of this history, deferential
review of the kind advocated by developer here is
no longer the rule after Snyder.
Under section 163.3215 citizen enforcement is
the primary tool for insuring consistency of
development decisions with the Comprehensive
Plan. Deference by the courts—especially of the
kind argued by the developer in this case—would
not only be inconsistent with the text and structure
of the statute, but it would ignore the very reasons
for adopting the legislation in the first place.
When an affected property owner in the area of a
newly allowed development brings a consistency
challenge to a development order, a cause of
action—as it were—for compliance with the
Comprehensive Plan is presented to the court, in
which the judge is required to pay deference only
to the facts in the case and the applicable law. In
light of the text of section 163.3215 and the
foregoing history, we reject the developer’s
contention that the trial court erred in failing to
defer to the County’s interpretation of its own
Comprehensive Plan.
Having thus decided that the trial court was
correct in failing to accord any particular
deference to the Martin County Commission in its
interpretation of the Comprehensive Plan, we now
proceed to consider the court’s determination on
the consistency issue. The trial court explained its
decision as follows:
“The primary claim by [plaintiffs] is that the
juxtaposition of multi-story, multi-family
apartments in Phase 10 directly next to the
single family homes in Phase 1 violates a
number of provisions in the Comprehensive
Plan. The provision of the Comprehensive Plan
that is central to their argument is section 4-
5(A)(2)(b), known as the ‘tiering policy.’ [see n.
6, above]
“The tiering policy was added to the
Comprehensive Plan … to address how
development would be added to existing singlefamily
residential communities. There was a
concern … over how existing single-family
homes were being impacted by new, adjacent
denser developments. …
“The tiering policy required…a transition zone
along the southern portion of Phase 10 equal to
‘the depth of the first block of single-family lots’
within the northern portion of Phase 1. The
section requires that development in the first tier
of Phase 10 be limited to construction ‘of
comparable density and compatible dwelling unit
types.’ The court finds that the appropriate
measure is 225 feet, using the shortest average
depth method of computation.
“No transition zone was established for Phase
10. The buildings along the first tier of Phase 10
are multi-family, multi-story, and have balconies.
The southern tier of Phase 10 has a density of
6.6 [UPA]. The overall density of Phase 10 is
6.5 [UPA]. There is no meaningful difference
in density across the entire western portion of
Phase 10. The northern tier of Phase 1, on the
other hand, is comprised entirely of single-family
homes on 0.75 acre to 1.2 acre lots, with a
density of 0.94 [UPA].
13“There was no first tier transition zone
established for Phase 10 as mandated by section
4-5(A)(2)(b). That section is not the only
provision of the Comprehensive Plan that
mandated compatible structures within the first
tier of Phase 10. Section 4-4(M)(1)(e)(2)
provided:
… Where single family structures comprise
the dominant structure type within [residential
estate densities (RE-0.5A)], new development
on undeveloped abutting lands shall be
13At this point in the Final Judgment, the court went
on to show in a comparative table that the change in
density between the two tiers represented a 560%
difference, the change in population a 492% difference,
and the number of units a 418% difference.
(11)
required to include compatible structure types of
lands immediately adjacent to existing family
development.
… Phase 1 is designated RE-0.5A
…
“It is impossible … to examine the photographs
of the homes in the northern tier of Phase 1, and
the apartment buildings in the southern tier of
Phase 10, and find that they are either
‘compatible dwelling unit types’ or ‘compatible
structure types.’ The only residential structure
that could be less compatible with the northern
tier of Phase 1, would be a multi-story
condominium building. There is no compatibility
between the structures in the southern tier of
Phase 10 and the northern tier of Phase 1.
Further, an examination of the density of
development in the two tiers at issue, precludes
this court from finding that they are in any way
comparable.
…
“[B]uffering does not grant relief to the
[developer] under section 4-4(I)(5). That
section deals with buffering between
‘incompatible land uses.’ The more specific
Tiering Policy mandates compatibility. More
importantly, even to the extent that the
Comprehensive Plan might, in some instances,
provide a builder with the ability to buffer
changes in density, intensity or uses, the
language of sections 4-4(M)(1)(e)(2) and 4-
5(A)(2)(b) simply do not permit the type of
development that is under construction in Phase
10.”
…
“Based on the foregoing, the Court finds that
the Development Order is inconsistent with the
Comprehensive Plan. It is not compatible with,
nor does it further the objective, policies, land
uses, densities and intensities in the
Comprehensive Plan. § 163.3194(3)(a).” [e.o.]
We have carefully reviewed the record of the
trial and the evidence presented. It is apparent
that there is substantial competent evidence to
support these findings. Developer argues that the
court erred in its interpretation of the “tiering
policy,” in deeming it a mandatory requirement
rather than a discretionary guide. We conclude
that the trial court’s construction is consistent with
the plain meaning of the text of the
Comprehensive Plan. See Comprehensive Plan,
§ 4-5(A)(2)(b) (“a density transition zone of
comparable density and compatible dwelling unit
types shall be established in the new project for a
depth from the shared property line that is
equivalent to the depth of the first tier of the
adjoining development’s lower density (i.e. the
depth of the first block of single-family lots).”).
Moreover, given the evidence as to Martin
County’s adoption of the tiering policy, the record
clearly supports the finding that the policy was
intended to be applied in all instances of projects
abutting single-family residential areas. We
therefore affirm the finding of inconsistency and
proceed to explain our decision on the remedy.
II. Remedy of Demolition
Developer challenges what it terms the
“enormity and extremity of the injunctive remedy
imposed by the trial court.” It argues that the trial
court’s order requiring the demolition of 5 multifamily
residential buildings is the most radical
remedy ever mandated by a Florida court because
of an inconsistency with a Comprehensive Plan.
Specifically, the contention is that the trial judge
failed to balance the equities between the parties
and thus ignored the evidence of a $3.3 million
dollar loss the developer will suffer from the
demolition of the buildings. The court failed to
consider alternative remedies in damages, it
argues, that would have adequately remedied any
harm resulting from the construction of structures
inconsistent with the Comprehensive Plan.
Developer maintains that the trial court
erroneously failed to give meaningful consideration
to the traditional elements for the imposition of
injunctive relief. It contends that the trial court
proceeded on an erroneous conclusion that where
an injunc tion is sought on the basis of a statutory
violation, no proof is required as to the traditional
(12)
elements for an injunction.
Traditionally, as the trial judge noted, it is true
that injunctions are usually denied where the party
seeking such relief fails to demonstrate a clear
legal right, a particular harm for which there is no
adequate remedy at law, and that considerations
of the public interest would support the injunction.
See, e.g., St Lucie County v. St. Lucie Village,
603 So. 2d 1289, 1292 (Fla. 4th DCA 1992).
These are, of course, the necessary ingredients for
equitable relief when we labor in the interplay of
common law and equity, where ordinary legal
remedies are unavailing.
Nonetheless, as between the State legislature
and the several counties, the Legislature is the
dominant creator of public duties and citizen
rights.
14 Recognizing that the Legislature has thesole power to create such public duties and citizen
rights, it logically follows that the Legislature is
necessarily endowed with the authority to spec ify
precisely what remedies shall be used by judges to
enforce a statutory duty—regardless of whether
in general usage such a remedy usually requires
additional factors before it is traditionally
employed.
When the Legislature creates a public duty and
a corresponding right in its citizens to enforce the
duty it has created, and provides explicitly that the
remedy of vindication shall be an injunction, the
Legislature has not thereby encroached on judicial
powers, as the courts held in Harvey v.
Wittenberg, 384 So. 2d 940 (Fla. 3rd DCA 1980),
and Times Publishing Co. v. Williams, 222 So. 2d
470 (Fla. 2d DCA 1969). The Times Publishing
court explained its theory of encroachment thus:
“Injunctive relief is an extraordinary remedy
which issues only when justice requires and
there is not adequate remedy at law, and when
there is a real and imminent danger of
irreparable injury. Statutory authority for such
writs, as in the act before us, are not
uncommon; but it must be remembered that
such writs are in the first instance judicial writs.
If such statutes purport to give the circuit courts
injunctive power they are ineffectual, since
those courts are otherwise vested with such
powers under the constitution, § 6(3) Art. V
Constitution of Florida; and if they purport to
dictate to such courts when, how or under what
conditions injunctions should issue they would
constitute an unlawful legislative infringement on
a judicial function.” [e.s.]
222 So. 2d at 476. Times Publishing and Harvey
both held that the Legislature is limited to
specifying certain harms as irreparable, but the
court alone has the discretion to determine
whether the injunction should otherwise issue. We
disagree with this analysis.
We think that is too wooden a construction of
legislative powers where a statute is concededly
valid. In our view when the Legislature provides
for an injunction in these circumstances, it has
deliberately made the new public duty and its
corresponding right of enforcement an integrated
statutory prescription. By specifying that the
public interest requires that a certain duty be
vindicated in the courts and not primarily within
other branches of government, the Legislature is
well within its powers. Surely the Legislature’s
primary role in defining public policy under the
constitution is broad enough to enable it to specify
a legal remedy in an enactment, regardless of
whether the traditional judicial restrictions on that
remedy in other, non-statutory contexts would limit
its usage. As the author of the primary duty, the
Legislature alone shapes the form of its
effectuating mechanism.
In section 163.3215, we think the Legislature
has constructed such a statute. The statute leads
off with a declaration that:
“Any aggrieved or adversely affec ted party
may maintain an action for injunctive or other
14
See Art. VIII, § 1(f) and (g), Fla. Const. (whethercharter or non-charter government, Counties are
granted power to enact only ordinances that are “not
inconsistent with general law”).
(13)
relief against any local government to prevent
such local government from taking any action on
a development order, as defined in s. 163.3164,
which materially alters the use or density or
intensity of use on a particular piece of property
that is not consistent with the comprehensive plan
adopted under this part.”
From the plain and obvious meaning of this text
we discern only two elements to the granting of an
injunction against the enforcement of a
development order: (a) the party is affected or
aggrieved by (b) an approved project that is
inconsistent with the Comprehensive Plan. In
short, the existence of an affected neighbor is all
that is necessary for the issuance of an injunction
against a proposed land use that is inconsistent
with the Comprehensive Plan.
We note that the statute does not say that the
affected/aggrieved party bringing the action
“creates a presumption of irreparable injury” by
showing an inconsistency with the Plan. See, e.g.,
§ 542.335(1)(j), Fla. Stat. (2000) (“The violation of
an enforceable restrictive covenant creates a
presumption of irreparable injury to the person
seeking enforcement of a restrictive covenant.”).
When the Legislature wants to make a lesser
intrusion on traditional equitable jurisdiction, it
obviously knows how to do so. Here the statutory
text makes the injunction the first and preferred
remedy to alleviate the affects of in inconsistent
land use. Hence, we read the statute to make the
injunction the presumed remedy where the
conditions prescribed are shown.
15We disagree with the developer’s contention
that this statute was meant to create mere
discretion in the court to issue an injunction. If
injunctive relief is the specified, primary remedy to
correct a violation of a public duty and to vindicate
the right of a person affected by the violation of
that duty, it can properly be deemed a rule that the
Legislature has created, not a grant of discretion.
Here the Legislature has devised an entire
statutory scheme to insure that all counties have a
Comprehensive Plan for the development of land
within their respective jurisdictions. The scheme
creates mandatory duties to have a plan,
mandatory duties to have the plan approved by the
state, and once approved mandatory duties to limit
all developments so that they are consistent with
the plan’s requirements. At the end of all these
mandatory duties—all these shalls—comes a new
relaxation of the requirements on standing for
citizen suits to enforce comprehensive land use
15We reject developer’s argument that demolition is
improper simply because Shidel failed to seek a
temporary injunction against any construction while
the case proceeded in court on the consistency issue.
In the first place, when the action was filed the trial
court originally thought its role limited to a record
review of the proceedings before the Martin County
Commission and concluded that no error had been
shown. Having decided there was no error in the
limited review it thought applicable, the trial court was
hardly likely to grant a temporary injunction while the
case was on appeal.
Even more important, however, we find nothing in the
text of the relevant statutes making such a request for
a temporary injunction a precondition to effective final
relief after a trial de novo when the court finds that the
permitted use is inconsistent with the Comprehensive
Plan. We note from other statutes that when the
Legislature means to place restrictions on third party
challenges to agency decisions granting permits, it
says so in specific text. Compare § 403.412(2)(c), Fla.
Stat. (2000), with § 163.3215(4), Fla. Stat. (2000), as to
preconditions for suit; see also § 163.3215(6), Fla. Stat.
(2000) (“The signature of an attorney or party
constitutes a certificate that he or she has read the
pleading, motion, or other paper and that, to the best of
his or her knowledge, information, and belief formed
after reasonable inquiry, it is not interposed for any
improper purpose, such as to harass or to cause
unnecessary delay or for economic advantage,
competitive reasons or frivolous purposes or needless
increase in the cost of litigation. If a pleading, motion,
or other paper is signed in violation of these
requirements, the court, upon motion or its own
initiative, shall impose upon the person who signed it,
a represented party, or both, an appropriate sanction,
which may include an order to pay to the other party or
parties the amount of reasonable expenses incurred
because of the filing of the pleading, motion, or other
paper, including a reasonable attorney's fee.”).
(14)
plans and providing for the issuance of injunctions
when an inconsistency affects another land
owner. Judicial construction of that sole remedy
as discretionary strikes us as remarkably
inconsistent with not only the text of the statute
itself but also with the purpose of the entire
legislative scheme.
Developer lays great stress on the size of the
monetary loss that it claims it will suffer from
demolition, as opposed to the much smaller
diminution in value that the affected property
owner bringing this action may have suffered. It
contends that a $3.3 million loss far outweighs the
evidence of diminution in the value of Shidel’s
property, less than $26,000. Its primary contention
here is that the trial judge erred in failing to weigh
these equities in its favor and deny any remedy of
demolition. Instead, as developer sees it, the court
should have awarded money damages to eliminate
the objector’s diminution in value. Developer also
argued that instead of demolition it should be
allowed to build environmental barriers, green
areas of trees and shrubbery, between the
apartment buildings and the adjoining area of
single family homes.
Developer emphasizes that we deal here with an
expensive development: “a high quality, upscale
project;” “forty units of high-quality garden
apartments;” “five upscale multi-family dwellings,
housing 40 garden apartments, at a value of
approximately $3 million.” Developer concedes
that there is evidence showing that plaintiff
Shidel’s property is diminished by $26,000. It also
concedes that the total diminution for all the homes
bordering its project is just under $300,000.
Developer contends, however, that the real
countervailing harm to all these affected property
owners in the vicinity is not any diminution in the
value of their homes, but instead is merely
“knowing that there is an upscale apartment
building approximately a football field away,
partially visible through some trees behind the
house.”
Section 163.3215 says nothing about weighing
these specific equities before granting an
injunction. If the Legislature had intended that
injunctive enforcement of comprehensive plans in
the courts be limited to cases where such
imbalances of equities were not present, we
assume that it would have said so. As important,
such balancing if applied generally would lead to
substantial non-compliance with comprehensive
plans. We doubt that there will be many instances
where the cost of the newly allowed construction
will be less than any diminution resulting from an
inconsistency. Entire projects of the kind
permitted here will frequently far exceed the
monetary harms caused to individual neighbors
affected by the inconsistency. In other words, if
balancing the equities—that is, weighing the loss
suffered by the developer against the diminution in
value of the objecting party—were required
before demolition could be ordered, then
demolition will never be ordered.
Moreover it is an argument that would allow
those with financial resources to buy their way out
of compliance with comprehensive plans. In all
cases where the proposed use is for multiple acres
and multiple buildings, the expenditures will be
great. The greater will be its cost, and so will be
a resulting loss from an after-the-fact demolition
order. The more costly and elaborate the project,
the greater will be the “imbalance in the equities.”
The more a developer is able to gild an
inconsistency with nature’s ornaments—trees,
plants, flowers and their symbiotic fauna—the
more certain under this argument will be the result
that no court will enjoin an inconsistency and
require its removal if already built.
In this case the alleged inequity could have been
entirely avoided if developer had simply awaited
the exhaustion of all legal remedies before
undertaking construction. It is therefore difficult
to perceive from the record any great inequity in
requiring demolition. Shidel let the developer
know when it was just beginning construction of
the first building that she would seek demolition if
(15)
the court found the project inconsistent. When
developer decided to proceed with construction in
spite of the absence of a final decision as to the
merits of the challenge under section 163.3215, the
developer was quite able to foresee that it might
lose the action in court. It could not have had a
reasonable expectation that its right to build what
it had proposed was finally settled. It may have
thought the decision to build before the
consistency question was settled in court a
reasonable “business decision,” but that hardly
makes it inequitable to enforce the rule as written.
It also seems quite inappropriate, if balancing of
equities were truly required by this statute, to
focus on the relatively small financial impacts
suffered by those adjoining an inconsistent land
use. The real countervailing equity to any
monetary loss of the developer is in the flouting of
the legal requirements of the Comprehensive Plan.
Every citizen in the community is intangibly
harmed by a failure to comply with the
Comprehensive Plan, even those whose properties
may not have been directly diminished in value.
We claim to be a society of laws, not of
individual eccentricities in attempting to evade the
rule of law. A society of law must respect law,
not its evasion. If the rule of law requires land
uses to meet specific standards, then allowing
those who develop land to escape its requirements
by spending a project out of compliance would
make the standards of growth management of
little real consequence. It would allow developers
such as this one to build in defiance of the limits
and then escape compliance by making the cost of
correction too high. That would render section
163.3215 meaningless and ineffectual.
In this regard we are drawn to the views
expressed in Welton v. 40 Oak Street Building.
Corp., 70 F.2d 377 (7th Cir. 1934), a case of
strikingly analogous facts. There the developer
applied for a permit to erect a building, and
proceeded to build while its neighbor objected to
the edifice and sought to show that the building
plans did not comply with the zoning ordinances.
When the agency approved the building he sought
relief in the courts, finally being victorious in the
state supreme court. Ownership of the building
meanwhile passed to a federal receiver, and so the
objecting neighbor sought to enforce his remedy
by injunctive relief in the federal court. The trial
judge denied an injunction. On appeal the Court of
Appeals disagreed and ordered a mandatory
injunction to “rebuild” the edifice in compliance
with the zoning law, explaining:
“We have earnestly endeavored to place
ourselves in a position to fully appreciate
appellees’ argument to the effect that
enforcement of a right which arises out of an
effort to give light and air to metropolitan areas
is an equity that is outweighed by the dollars
advanced by builders of twenty story buildings in
defiance of zoning ordinances. We have also
endeavored to obtain appellees’ viewpoint when
they propose a money judgment to one who
suffers small financial loss as satisfaction for
violation of important ordinances enacted for the
benefit of the public. In the fight for better living
conditions in large cities, in the contest for more
light and air, more health and comfort, the scales
are not well balanced if dividends to the
individuals outweigh health and happiness to the
community. Financial relief to appellants is not
the only factor in weighing equities. There is
involved that immeasurable but nevertheless
vital element of respect for, and compliance
with, the health ordinance of the city. The
surest way to stop the erection of high buildings
in defiance of zoning ordinances is to remove all
possibility of gain to those who build illegally.
Prevention will never be accomplished by
compromise after the building is erected, or
through payment of a small money judgment to
some individual whose financial loss is an
inconsequential item.”
70 F.2d at 382-83. We agree with the Seventh
Circuit that respect for law, in this case the
Comprehensive Plan, trumps any “inequity” of
financial loss arising from demolition.
(16)
Our understanding of section 163.3215 is thus
different from equity’s traditional use of its
remedies. If, as we have shown, an injunction is
the statutory remedy to insure consistency of
development of property within the county, it does
not seem to us that the kind of balancing
advocated here would further that goal. In fact it
would very likely lead to even more inconsistent
development, particularly as to the kind of large
scale projec t involved here with multiple buildings
for multiple families. As we see it, the purpose of
this statute is precisely against this kind of
thinking. A clear rule is far more likely to erase
the kind of legal unpredictability lamented by
developer and amici.
The statute says that an affected or aggrieved
party may bring an action to enjoin an inconsistent
development allowed by the County under its
Comprehensive Plan. The statutory rule is that if
you build it, and in court it later proves
inconsistent, it will have to come down. The
court’s injunction enforces the statutory scheme
as written. The County has been ordered to
comply with its own Comprehensive Plan and
restrained from allowing inconsistent development;
and the developer has been found to have built an
inconsistent land use and has been ordered to
remove it. The rule of law has prevailed.
We therefore affirm the final judgment of the
trial court in all respects.
GUNTHER and GROSS, JJ., concur.
NOT FINAL UNTIL DISPOSITION OF ANY TIMELY
FILED MOTION FOR REHEARING.
TDR Case Studies Updates
Beyond Takings and Givings contains case studies of 142 TDR programs in 134 communities around the nation. Since that book went to press in January 2003, TDR programs have been adopted, discovered or updated in the following communities. Rick Pruetz, who prepares these profiles, runs a consulting practice specializing in TDR workshops, studies and ordinances. Please contact him at arje@attglobal.net with corrections, updates or information on additional programs.
Chesterfield Township, Burlington County, New Jersey
Los Ranchos de Albuquerque, New Mexico
Lumberton Township, Burlington County, New Jersey
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Approved
Appraiser List Application |
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Aquatic Plant Removal Permit Application (pdf 35k, requires Acrobat Reader) |
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Application for processing and collecting aquatic plants for Importation, Transportation, Non-Nursery Cultivation, Possession, and Collection (pdf 95k, requires Acrobat Reader) Rules |
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Application for removing aquatic plants (pdf 35k, requires Acrobat Reader) Rules |
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DEP 63-030 (16) (doc) Application for Recordable Document for Lands Filled Prior to July 1, 1975 Pursuant to Chapter 253.12(9) & (10), Florida Statutes |
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Affidavit Example for Lands Filled Prior to July 1, 1975-"75 Certificate" |
|
DEP 63-031 (16) (doc) Application for Disclaimers to Confirm Title of Formerly Sovereignty Lands Pursuant to Chapter 253.129, Florida Statutes |
|
DEP 63-032 (16) (doc) Application for Quitclaim Deed to Clear Title of Formerly Sovereignty Lands Pursuant to Chapter 253.12(6), Florida Statutes |
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DEP 62-068 (16) (doc) Application to Purchase Lands Lost Due to Artificial Erosion or Artificial Erosion and Avulsion |
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DEP 62-069 (16) (doc) Application for Disclaimer for Lands Lost Due to Avulsion |
SMATHERS LIBRARIES |
---Web Resources for Urban Planning |
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Introduction
This guide provides links to websites of high quality of likely interest to researchers in architecture. Recommendations for additions or revisions to this guide are welcomed. This guide is one of three which make up the Architecture Subject Guide. The other guides deal with Reference Collection sources and Databases.-
|
Planning
Subject Guide | AFA Library | UF
Libraries | UF
Julie Quick (202) 720-4632
Mary Cressel (202) 690-0547
VENEMAN ANNOUNCES RELEASE OF $1.6 BILLION FOR VOLUNTARY CONSERVATION PROGRAMS ON WORKING LANDS
WASHINGTON, Oct. 22, 2004—Agriculture Secretary Ann M. Veneman today announced the release of $1.6 billion in fiscal year 2005 funding for conservation programs on working lands, which, by knowing the initial mandatory program funding and technical assistance levels well before the next planting season begins, will help producers connect their business decisions to protecting water, air, soil and wildlife.
"This is one of the largest investments in conservation on private lands in our nation’s history," Veneman said. "In making the announcement today, we are responding to agricultural producers who want greater certainty and predictability in their decisions regarding environmental stewardship before planting season begins."
Veneman said that these program funds were being provided much earlier than in the past.
"Releasing the funds earlier in the year gives farmers and ranchers more time to make sound decisions regarding conservation practices," said Veneman. "This announcement will make conservations programs fully operational in every state and give producers the information they need to develop more effective conservation plans."
Veneman added that this effort is another example of the Bush Administration’s commitment to providing the tools and resources that will help agriculture producers remain the best stewards of the land. For example, on Earth Day 2004, President Bush highlighted the progress made by USDA in restoring America’s wetlands and announced an aggressive national goal to increase overall wetland acres and quality by restoring, improving and protecting at least 3 million wetland acres over the next five years. To help meet this goal, the President called on Congress to pass his FY 2005 Budget request, which includes $4.4 billion for conservation programs. By surpassing the decade-old "no-net-loss" policy, the President sent a message that we can continue the fight against soil erosion, improve the quality of our water and air and enhance wildlife habitat across America’s productive agricultural landscape.
In August, the President announced an expansion of the Conservation Reserve Program (CRP). As part of this announcement, the President unveiled CRP initiatives to create 250,000 acres of habitat for the northern bobwhite quail and to restore 250,000 acres of wetlands and playa lakes located outside the 100-year floodplain.
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In September, the President issued an Executive Order, Facilitation of Cooperative Conservation, which promotes cooperative conservation. The Executive Order emphasized appropriate local participation in Federal decision-making, in accordance with respective agency missions, policies and regulations. Cooperative conservation will enhance the enjoyment of natural resources through greater protection of the environment by involving collaborative activity among Federal, State, local and tribal governments, private for-profit and nonprofit institutions, other nongovernmental entities and individuals.
To help implement these initiatives, the Administration is announcing the initial conservation funding allocation today to allow USDA’s Natural Resources Conservation Service (NRCS) conservationists to work with farmers and ranchers nationwide to improve soil, water, air and at-risk habitat on privately-owned working lands in several programs.
Fiscal year 2005 allocations include $1.310 billion in financial assistance and $306 million for technical assistance for NRCS voluntary conservation programs and other activities. Veneman said that States will receive additional money after Congress makes discretionary funding decisions.
With financial and technical assistance from NRCS, farmers, ranchers and other landowners will continue to address resource concerns on agricultural working lands, promote environmental quality, address challenges in water quality and quantity, protect prime farmland and grazing lands and protect valuable wetlands ecosystems and wildlife habitat.
Key conservation programs and allocations include:
Environmental Quality Incentives Program (EQIP): $793,590,395. EQIP assists farmers and ranchers to improve soil, air and water quality and other related resources on private working lands.
Ground and Surface Water Conservation (GSWC): $62,874,481. GSWC assists farmers and ranchers to conserve our nation’s ground and surface water resources. The funding will result in improving agricultural water use efficiency and result in a net savings to ground and surface water reserves.
Klamath Basin: $9,734,200. These funds will help farmers and ranchers to enhance water quality, reduce water usage by increasing irrigation efficiencies, and improve habitat for affected fish and wildlife in the Klamath Basin.
Wetlands Reserve Program (WRP): $244,533,800. WRP is a voluntary program that helps landowners restore, enhance and protect wetlands through permanent easements, 30-year easements and restoration cost-share agreements. The program works to maximize wildlife habitat and wetland functions and values.
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Farm and Ranchland Protection Program (FRPP): $66,574,678. FRPP is a voluntary program that provides matching funds to state and local governments and non-governmental organizations to purchase conservation easements on farm and ranch land. Since 1996, FRPP, in partnership with state and local governments and nongovernmental organizations, has protected over 440,000 acres.
Grassland Reserve Program (GRP): $40,832,400. GRP is a voluntary program designed to protect and restore grasslands, biodiversity, wildlife habitat and reduce soil erosion while sustaining viable working ranches. In 2005, GRP will utilize over $2 million to benefit the Greater Sage Grouse in key western states and protect precious Tall Grass habitat in Kansas.
Wildlife Habitat Incentives Program (WHIP): $21,935,051. WHIP offers technical and financial assistance through long-term agreements to create, restore and enhance wildlife habitat for upland wildlife, wetland wildlife, threatened, endangered or at-risk species and fisheries as well as other types of wildlife.
Agricultural Management Assistance (AMA): $12,997,456. AMA is available in 15 states where participation in the Federal Crop Insurance Program has been historically low: Connecticut, Delaware, Maine, Maryland, Massachusetts, Nevada, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Utah, Vermont, West Virginia and Wyoming. It helps farmers and ranchers voluntarily address natural resource concerns by incorporating conservation into farming operations while managing financial risk.
Conservation Reserve Program (CRP): $56,599,700 in technical assistance. CRP, administered by the Farm Service Agency, encourages farmers and ranchers to voluntarily establish conservation practices to protect environmentally sensitive land, provide food and habitat for wildlife and protect ground and surface water from runoff and sedimentation. Since the inception of CRP in 1986, this program has helped reduce soil erosion by more than 40 percent and restored 1.8 million acres of critical wetland acreage.
In addition, the allocation includes dollars for the Conservation Security Program (CSP). It includes $32,386,009 for active contracts and $162,024,991 for 2005 sign-up. State allocations for sign-up will be made at a later date. CSP recognizes those producers who are excellent stewards of the land and are willing to do even more by supporting ongoing conservation stewardship of agricultural working lands. In 2004, CSP was offered in 18 watersheds. In 2005 it is expected to be available in watersheds in all 50 states and a renewable energy component will be introduced that rewards farmers and ranchers for converting to renewable energy fuels such as soy bio-diesel and ethanol, for recycling 100 percent of on-farm lubricants, and for implementing energy production, including wind, solar, geothermal, and methane production.
A list of allocation totals by states is attached. Additional information on conservation programs is available at http://www.nrcs.usda.gov/programs. Landowners who want specific information regarding program participation should contact their local USDA Service Center or NRCS office, locate at http://offices.usda.gov or in the telephone book under Federal Government, U.S. Department of Agriculture.
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FY 2005 Conservation Funding Allocation Totals by State:
|
FLORIDA |
$39,180,466 |
* State allocations for CSP sign-up will be made at a later date.
S
TUDYA
NALYSIS OF AGRICULTURAL LANDR
ETENTION STRATEGIEST
ASK 2.B.S
UBMITTED BY:R
OBERT H. FREILICH, AICP, LL.M., J.D.T
YSON SMITH, AICP, J.D.E
LISA PASTER, M. SC.F
REILICH, LEITNER & CARLISLEWITH SUPPORT FROM
T
ISCHLER & ASSOCIATESAND
U
NIVERSITY OF FLORIDAMiami-Dade County Agriculture and Rural Area Study
Task 2(b)
doc.#55985;v.2/90685.001
1
T
ABLE OF CONTENTSI. Introduction..................................................................................................................2
A. Task 2: Agricultural and Rural Area Retention and Promotion Strategies .............2
B. Task 2(b): Analysis of Agricultural Land Retention Strategies ..............................2
C.
The Goal: Protection of Agricultural Land Values and the Essential Character ofthe Study Area .................................................................................................................3
II. Overview......................................................................................................................4
A. Land Use Growth Patterns .......................................................................................4
B. Agricultural Land .....................................................................................................6
C. Economic Impact of Agricultural Land ...................................................................7
D. Growth Management Challenges ............................................................................7
III. Agricultural and Rural Land Policies and Implementation Techniques..................8
A. Agricultural Zoning .................................................................................................8
1. Area Based Zoning ..............................................................................................9
2. Large Lot Zoning .................................................................................................9
3. Cluster Zoning ...................................................................................................10
4. Buffering............................................................................................................12
5. Overall Benefits and Drawbacks of Agricultural Zoning..................................14
B. Non-Zoning Techniques ........................................................................................15
1. Right-to-farm Laws ...........................................................................................15
2. Agricultural Districting......................................................................................17
3. Land Evaluation Systems ..................................................................................18
C. Land Acquisition Programs ...................................................................................20
1. Conservation Easements ....................................................................................20
2. Purchase of Development Rights.......................................................................20
3. Land Banking.....................................................................................................22
4. Transfer of Development Rights .......................................................................23
5. Florida Rural and Family Lands Protection Act ................................................26
D. Taxation Programs .................................................................................................27
1. Differential Assessment .....................................................................................27
2. Circuit Breaker Tax Relief Credits ....................................................................28
3. Real Estate Transfer Taxes ................................................................................29
E. Funding Programs..................................................................................................30
1. Impact Fees ........................................................................................................30
2. Environmental Mitigation Fees .........................................................................31
3. Federal Programs ...............................................................................................31
F. Regulatory Techniques ..........................................................................................32
1. Growth Tiers ......................................................................................................32
2. Concurrency Programs ......................................................................................33
3. Urban Service Boundaries .................................................................................34
IV. Economics and the Law.........................................................................................35
A. Economic Value of Land .......................................................................................35
B. Legal Framework ...................................................................................................35
1. Takings ..............................................................................................................36
2. Impact Fees/ Mitigation Fees.............................................................................37
3. Due Process .......................................................................................................38
V. Miami-Dade County – Value Preservation Principle ................................................38
VI. Conclusion.............................................................................................................39
Miami-Dade County Agriculture and Rural Area Study
Task 2(b)
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The authors have prepared this analysis in completion of Task 2(b)
of the Scope of Services, “Agricultural and Rural Area Retention and
Promotion Strategies.” It is not the goal of this analysis to propose one
solution or another as appropriate to the Study Area, or to suggest one
policy approach over any other. Rather, this analysis is intended to set
forth alternative techniques that the CAC may recommend and the County
may adopt in pursuit of its overarching land use objectives in the Study
Area.
Tyson Smith, of the law firm, Freilich, Leitner & Carlisle, and coauthor
of this analysis, attended the August 21, 2002 meeting of the CAC,
presented the findings made herein, and received the initial input of the
Committee. This Report reflects the comments received at that meeting,
as well as additional comments received from other members of the
Consultant Team, staff, and the TAC.
The Task 2(c) report, “Analysis of Rural Land Uses,” presents a
case analysis of five different communities around the country that have
incorporated a number of the preservation techniques discussed in this
report. In Task 2(c) we focused on the “value preservation” mechanisms –
e.g.
, purchase or transfer of development rights – applied by thecommunities to achieve successful agriculture and rural area programs.
Value preservation mechanisms make most programs successful, due
mainly to the fact that they protect both the agricultural and the
preservation interests of the community. This Report provides an
overview of zoning and incentive driven programs that may, in the final
analysis, constitute the ultimate recommendation of the Consultant Team.
I. I
NTRODUCTIONA. Task 2: Agricultural and Rural Area Retention and Promotion Strategies
Task 2 of the Scope of Services focuses on a range of agriculture and rural area
retention, promotion, and economic development strategies. Task 2(a) presents and
analyzes information on various economic development issues; Task 2(c) introduces
related programs used in similarly situated rural areas of the country; and, finally, Task
2(d) will include a recommended approach for addressing the specific needs of Miami-
Dade County.
B. Task 2(b): Analysis of Agricultural Land Retention Strategies
Objective:
Collect, analyze and present information regardingagricultural land retention strategies and implementing programs used in
areas facing similar urbanization pressures, as well as development rights
programs, land swaps, or any other means to ensure that landowner
equity is maintained, with emphasis on the success of such programs, their
ability to solve shortcomings and their applicability to Miami-Dade
County without negative effects on agricultural competitiveness.
Miami-Dade County Agriculture and Rural Area Study
Task 2(b)
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3
The goal of Task 2(b) is to present and analyze information regarding agricultural
and rural land use strategies and programs used in areas facing development pressures
similar to those in existence or anticipated in the Study Area. Section II of this Report
provides a general overview of the range of issues that underlie the overall analysis being
undertaken by the Consultant Team (the “Team”). Section III sets out numerous
agriculture and rural land use techniques that are available to the County in pursuit of its
overall rural policies. Section IV assesses the applicability and legality of various land
use policies and preservation techniques within the Study Area. And, finally, Section V
sets forth the proposed framework for analyzing or determining a policy approach that
will achieve the dual goal of this analysis: the protection of land values and the
preservation of agriculture and rural open space within the Study Area.
C.
The Goal: Protection of Agricultural Land Values and the EssentialCharacter of the Study Area
Preserving the value of agricultural land is imperative to ensuring long term
preservation of farming, open space, and managed growth. Farmers, growers, and
ranchers own 80 percent of the private land in Florida; land that provides wide-open
views of forestlands, green groves, and pastureland.
1 However, many of these large-scaleproperty owners are selling their land because encroaching urban uses have deemed
agricultural uses economically non-viable. When land value is diminished, future
economic development is limited. During times of economic hardship, the agricultural
landowner may have to rely on the underlying value of his or her land to make financing
arrangements to cover the cost of operations. If land values are significantly reduced, so
are refinancing opportunities, leaving the farmer in difficult financial straits. Preserving
land values is beneficial not only for the land owner, but also for the entire community;
while the farmer continues to farm, the community benefits from open space and
managed growth.
This paper concludes with a proposal for analyzing and developing a “preferred
development scenario” for achieving the long-term land use goals for the Study Area.
The authors propose that this analysis – this weighing of alternative techniques and
approaches – be conducted in light of the actual economic reality that landowners in the
Study Area will face over a twenty-year period. Simply put, that decision will be
whether to retain existing holdings in their current use, or a significant portion thereof; or
to develop those holdings at some undetermined urban or suburban density.
The framework of this analysis presumes, first, that a combination of
agriculture/rural open space preservation and reasonable development will characterize
the Study Area over the next twenty years. Second, it further presumes that this
combination of land use intensities will be defined by adopted County policies, which in
turn, may be based significantly on the recommendations of the Team and the Citizens’
Advisory Committee (the “CAC”). Third, this analysis contemplates an ultimate
“preferred development scenario” – to be determined and articulated under Task 2(d) –
that preserves both property rights and rural character, but neither at the expense of the
1
Florida Farm Bureau, Growth Management, available athttp://www.fb.com/flfb/issues/2001/Growmgt.htm
(August 2, 2002).Miami-Dade County Agriculture and Rural Area Study
Task 2(b)
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4
other. The authors believe that reasonable policies can be drafted and implemented,
which will advance both property rights and the rural policies of the County, while
protecting land values throughout the Study Area. The Alternatives Analysis set forth at
Section V proposes a framework for arriving at that ultimate recommendation.
II. O
VERVIEWA. Land Use Growth Patterns
Florida is one of the fastest growing states in the nation, and rural lands still
constitute a majority of land within the state.
2 While rural populations accounted for only7 percent of the state’s population in 1997, the growth rate of rural Florida has been
outpacing the national average.
3 From 1990 to 2000, the population of Miami-DadeCounty grew 12.3 percent.
4Historically, Miami-Dade County’s land use patterns have reflected patterns
across America: loss of agricultural land to urban development; rising land prices on the
urban fringe; and urban sprawl. Since World War II the greatest proportion of growth
has taken place in the urban-rural fringes of major metropolitan centers. This type of
growth has led to the depletion and deprivation of important environmental resources,
including the loss of unique agricultural lands.
5 As urban growth spreads into the ruraland semi-rural areas of Miami- Dade County, the character unique to the rural community
is threatened.
6In 1985, the Florida Legislature passed into law the Local Government
Comprehensive Planning and Land Development Regulations Act (the “Growth
Management Act”). The Growth Management Act set up a public hearing and permitting
process for regional planned growth that protects important public natural resources
including rivers, lakes, springs, state parks, and rare wildlife species. The Growth
Management Act mandates comprehensive planning for local governments and vested the
Florida Department of Community Affairs (DCA) with an oversight role. From local to
regional to statewide comprehensive plans, DCA provides checks and balances to growth
and development, ensuring that developers and existing taxpayers alike foot some of the
costs associated with growth such as new schools, roads, new utilities (drinking water,
sewage treatment, electric, telephone), municipal services (fire, police, ambulance), and
additional parks and recreation areas.
7The County’s Comprehensive Development Master Plan and its accompanying
Land Use Planning (LUP) map guide land use patterns in Miami-Dade County. The
Urban Development Boundary (UDB) is one of the major components of the land use
strategy in Miami-Dade County as it demarcates where urban development ends and rural
2
Florida Chapter of the American Planning Association & 1000 Friends of Florida, Rural Florida:Opportunities for the Future
, 3 (February 2002).3
Id.4
South Florida Regional Planning Council, Table: Southeast Florida Components Of Population Changeavailable at
http://www.sfrpc.com/region/sfcmigc1.htm (August 1, 2002).5
Robert H. Freilich & Linda Kirts Davis, Saving the Land: The Utilization of Modern Techniques ofGrowth Management to Preserve Rural and Agricultural America
, 13 URB. LAW. 27, 29 (1981).6
See Fred Heyer, Perserving Rural Character, APA Planning Advisory Service Report no. 429, 1 (1990).7
See generally Fla. Stat. §163 (2002).Miami-Dade County Agriculture and Rural Area Study
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development begins.
8 The purpose of the UDB is to ensure that development only occursin areas where infrastructure is available and to ensure vital natural resources are
protected outside the boundary. Development within the UDB will be approved through
the year 2005 provided that adequate services and public facilities are available.
9 TheLUP also has a year 2015 Urban Expansion Area (UEA) boundary. The UEA is
comprised of that area located between the 2005 UDB and the 2015 UEA boundary. It is
the area where current projections indicate that further urban development beyond the
2005 UDB boundary is likely to occur between 2005 and 2015. Until this area is brought
into the UDB area through plan and review amendment processes, parcels are allowed to
be used for agricultural and open space use.
10Any person or organization, including the federal government, the State of
Florida, Miami-Dade County, any municipality in Miami-Dade County and any of their
agencies, authorities and departments may request amendment of the UDB and UEA.
The County Commission must review the Comprehensive Development Master Plan
every two years and any proposed amendment to the UDB may only be submitted in odd
years during a certain period in April.
11 In considering amendments to the UDB theCommission must meet all the requirements of the Growth Management Act and will
consider issues such as population trends, demand on urban services, levels of service
available, development right demand, infill potential, environmental and agricultural
resources, and above all concurrency, which demands that local government phase
development so it occurs only after urban facilities or infrastructure have been provided.
In December of 1996, the Miami-Dade County Board of County Commissioners
passed Resolution No. 1477-96 establishing an Infill Strategy Task Force to study
opportunities and strategies to promote infill within the UDB. The Task Force’s 1997
final report recommended, among other things, that the UDB not be expanded for at least
ten years and that the policy of discouraging infrastructure investment outside the UDB
be continued.
12Comprehensive Development Master Plan policies reflect the need to discourage
sprawl development outside the UDB in order to preserve agriculture. Policy 8G states
that the UDB should contain developable land having capacity to sustain projected
countywide residential demand for a total period of 15 years after adoption of the most
recent Evaluation and Appraisal Report.
13 Policy 8H further indicates that whenconsidering land areas to be added to the UDB, the Redland area (a prime agricultural
location) shall not be cons idered, and land designated for agricultural land uses on the
LUP shall be avoided.
14 The Comprehensive Development Master Plan also indicatesthat the principal uses in the “Agriculture” district should be agriculture and uses
ancillary to and directly supportive of agricultural. While uses ancillary and necessary to
agriculture may be permitted, the County should consider whether future schools should
8
MIAMI-DADE COUNTY, COMPREHENSIVE DEVELOPMENT MASTER PLAN at I-45 (2001).9
Id.10
Id. at I-46.11
MIAMI-DADE COUNTY ZONING CODE, Sec. 2-116.1. (2002).12
MIAMI-DADE COUNTY, supra note 8, at I-45.13
Id. at I-16.14
Id at I-17.Miami-Dade County Agriculture and Rural Area Study
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be located outside the agricultural area within the urban development areas of the
County.
15Though some agriculturally zoned land exists within the UDB, no new
commercial agricultural use of property may be established within the boundary (though
limited exceptions exist).
16 This is consistent with a countywide strategy to maximizedensities and urban uses within the UDB and to maximize preservation of land values
within the community. Conversely, there are lands that are zoned agricultural within the
UDB but are re-designated for urban development pursuant to amendments to the
Comprehensive Development Master Plan in 1995. These lands shall be converted only
pursuant to policies within the Comprehensive Development Master Plan and contingent
on a Farmland Conservation Study.
17Residential development is only permitted at a density of one unit per five acres
(1:5). Smaller residential parcels may be created only if the immediate area surrounding
the subject parcel on three sides is predominately parceled in a similar manner and if
division of the subject parcel would not encourage further land division in the area.
18 Nobusiness or industry (with the exception of packing houses) is allowed in the Agriculture
district unless it is directly related to agricultural uses, is located on an existing arterial
roadway, and a adequate water supply and sewage disposal exists in accordance with
County law. Other uses compatible with agriculture and rural residential character may
be approved based on a determination of public necessity or public interest; or if the
applicant can prove no other suitable site exists outside the Agriculture district.
19B. Agricultural Land
There are approximately 1.55 million acres in Miami-Dade County, ¾ of which
are under water, in water conservation areas or considered submarginal for urban or
agricultural uses.
20 Agricultural uses in Miami-Dade County are located in the southcentral portion of the County, also known as the Redland. There are considerable urban
land uses scattered throughout this agricultural area.
According to the Census of Agriculture, land devoted to agriculture has remained
fairly stable since the 1980s, ranging from 83 to 87 thousand acres, or approximately 7
percent of total county acreage.
21 While the number of farms declined by 17 percent to1,576 since 1992, the acreage of land devoted to agriculture actually increased 1.7
15
Id. at I-47.16
Id at I-45.17
Id at I-46.18
Id.19
Id.20
ROBERT DEGNER, TOM STEVENS, DAVID MULKEY, & ALAN HODGES, FLORIDA AGRICULTURALM
ARKETING RESEARCH CENTER, ECONOMIC IMPACT OF AGRICULTURE AND AGRIBUSINESS IN MIAMI-DADEC
OUNTY, FLORIDA p. x (2000).21
Id.Miami-Dade County Agriculture and Rural Area Study
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percent in the same period to 85,093 acres.
22 Agricultural land in Miami-Dade County isconsidered to be among the most threatened in the nation.
23Government agencies have played a significant role in the purchase of agricultural
land for conservation purposes. Between 1975 and 1998 over 10,300 acres of farmland
were purchased by governmental agencies, in particular by the South Florida Water
Management District (SFWMD). In 2000 it is estimated that the SFWMD leased
approximately 5,000 acres to private individuals.
24C. Economic Impact of Agricultural Land
Florida ranks in the top 10 states in total market agricultural value and its market
value per acre of farmland is also among one of the top ten producing states.
25 The totaleconomic impact from all agricultural sales originating in Miami-Dade County exceeded
$1.07 billion for the 1997-98 crop year. Fresh vegetable production was the largest
contributor to this total with nearly $491 million, or 45.6 percent of the total. The
greenhouse/nursery industry was responsible for nearly 41 percent or $439.8 million of
the total economic impact. Although sales revenues generated by nurseries and
greenhouses exceeded revenues for vegetables by over $7 million during this period, a
greater proportion of vegetables are shipped outside the County, thereby generating more
"new" dollars and a greater economic impact. Sales of tropical fruits produced in the
County created an economic impact of $137 million, representing about 12.7 percent of
agriculture’s value. Miscellaneous livestock sales, including aquaculture, generated an
economic impact of about $8.2 million, representing less than one percent (1%) of
agriculture's total economic impact.
Agriculture created an estimated 14,795 jobs in Miami-Dade County for 1997/98.
Agriculture's impact on earnings in Miami-Dade County totaled over $362 million for
1997-98. Approximately 46.5 percent, or $168 million, of this earnings impact was
generated by the vegetable industry. More than 42 percent, or approximately $153
million, was contributed by the greenhouse and nursery subsector. The tropical fruit
subsector generated nearly $41 million (11.2 percent) and miscellaneous livestock was
responsible for $450 thousand (0.12 percent) of agricultural earnings impact for Miami-
Dade County in 1997.
26D. Growth Management Challenges
Miami- Dade County must establish alternative development patterns to encourage
managed growth and preserve values of agricultural land. Growth management
techniques must preserve the value of agricultural land, the environment, and
development rights while protecting urban viability and stability.
22
Id.23
American Farmland Trust, Farming on the Edge (1997) available athttp://www.farmlandinfo.org/cae/foe2/
(July 31, 2002).24
DEGNER, supra note 20, at x.25
American Farmland Trust, supra note 23.26
DEGNER, supra note 20, at x-xi.Miami-Dade County Agriculture and Rural Area Study
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Implementation of a program must be legally defensible. Statutorily, local
government is required to protect and preserve land and to mitigate impacts on
environmental lands.
27 However, in fulfillment of state mandate, private property rightsadvocates may view any scheme that reduces land values as a taking under the Fifth
Amendment of the U.S. Constitution, the Florida Constitution, or the Bert J. Harris Act.
28Governments must balance the need to protect health, welfare and safety with the
guarantee for compensation for land that is taken for public purposes. The land use
program for Miami-Dade County must strive to strike equilibrium between these
competing interests.
Agricultural preservation must be part of a wider comprehensive planning
program. Community input is vital to enhance the quality of planning. Agricultural
landowners bring specific information about their needs to the table. In the long run, a
plan that combines planning and agricultural knowledge will enhance the quality of the
plan. An extensive public input process will also help to avoid unnecessary contention
between self-interested parties, including urban and agricultural dwellers and the
government. An effective public input process allows interests to resolve their
differences prior to adoption of any plan, and to ensure that the plan addresses the needs
of different groups.
III. A
GRICULTURAL AND RURAL LAND POLICIES AND IMPLEMENTATION TECHNIQUESThis section focuses on techniques for agriculture and rural land retention. The
underlying goal is to: (1) achieve preservation of the lands most suitable for future
agricultural use; (2) achieve preservation of agricultural land values; and (3) preserve the
rural character of the area.
A. Agricultural Zoning
Zoning is the most utilized technique for preserving agriculture and rural lands.
Zoning land exclusively for agricultural uses prevents residential subdivisions while
simultaneously creating a holding zone to restrict urban expansion.
29Miami- Dade County has a specific zone, an AU zone, that allows agricultural and
related uses including packing facilities, outdoor storage of farming equipment, farming,
cattle grazing, hog and dairy farms (but only after approval at a public hearing),
nurseries, greenhouses, groves, truck gardens, single-family homes, schools, day cares,
and group homes. Minimum lot size for a residential lot is five acres.
27
Julian Conrad Juergensmeyer, James C. Nichols, & Brian D. Leebrick, Transferable Development Rightsand Alternatives After Suitum
, 30 URB. LAW. 441, 443 (1998).28
Id.29
ROBERT H. FREILICH, FROM SPRAWL TO SMART GROWTH: SUCCESSFUL LEGAL, PLANNING, ANDE
NVIRONMENTAL SYSTEMS 284 (American Bar Association 1999).Miami-Dade County Agriculture and Rural Area Study
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9
1. Area Based Zoning
Fixed area based zoning allows for one dwelling unit for a specified number of
acres. For example, the zoning ordinance in Lancaster County, Pennsylvania (See Task
2(c) Report) allows for one non-farm lot for every 50 acres. A non- farm lot subdivided
from its parent tract must be at least one acre, but not more than two.
30 Similarly, thequarter-quarter approach operates by splitting off land from the parent parcel, and
establishing a maximum or minimum parcel size for building lots.
31Sliding scale zoning is another agricultural protection technique in which the
number of dwelling units permitted varies with the size of the tract. Owners of smaller
parcels may divide their land into more lots on a per-acre basis than owners of larger
parcels.
32 Sliding scale zoning may also be used by qualitatively assessing land. Forexample, Clinton County, Indiana allows denser development on lands with poor soil
quality and prohibits development on lands with high soil quality.
33The rationale behind sliding scale zoning is to promote development on smaller
tracts that are on less valuable soil while prohibiting development on fertile, soil rich
lands.
34 High-density development also satisfies the legal requirement that municipalitiespermit some economically viable use of land when farming is not profitable.
35Critics of area based zoning suggest that a successful program must require that
properties be restricted with conservation easements to prevent further development after
the maximum density is reached.
36 Communities that do not require conservationeasements or some other type of deed restriction will be in danger of losing the land to
non-agricultural uses in the future. The other potential problem with area based zoning is
that, like any zoning ordinance, it only exists as long as the political will to maintain and
enforce it exists. Communities must be willing to commit to this type of zoning over an
extended period of time for it to be successful.
On the other hand, this type of zoning is a very inexpensive way to protect land
because little public expenditure is necessary. Compared to other programs such as
TDRs or PDRs (discussed below), zoning can be implemented very quickly, and,
furthermore, the public is accustomed to these traditional zoning techniques.
2. Large Lot Zoning
Some communities have tried to slow rapid growth patterns by requiring rural
land to be subdivided into lots no smaller than five or more acres, with the intention that
30
AMERICAN FARMLAND TRUST , SAVING AMERICAN FARMLAND: WHAT WORKS 59 (1997).31
METROPOLITAN MIAMI-DADE COUNTY PLANNING DEPARTMENT & METROPOLITAN MIAMI-DADEC
OUNTY COOPERATIVE EXTENSION DEPARTMENT, MANAGEMENT OPTIONS EVALUATED FOR THER
ETENTION OF LAND FOR AGRICULTURE IN DADE COUNTY, FLORIDA 76 (1981).32
AMERICAN FARMLAND TRUST , supra note 30, at 31733
Id.34
Id. at 60.35
Id. at 60.36
Id. at 59.Miami-Dade County Agriculture and Rural Area Study
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larger parcels will maintain lower density and rural character. The intent also is to
protect water quality and environmental resources. As a rule of thumb, the minimum lot
size created is the amount of land necessary to carry on a successful farming operation,
thus, lot sizes reflect the economic reality of agriculture.
37Though large lot zoning was a traditional strategy to protect farmland in the 1970s
and 80s, the resulting development of subdivisions has suggested that it may not be the
most effective strategy. The main problem is that the lot size is not large enough to
discourage development, yet is too small for effective agriculture.
38Large lot zoning, therefore, is widely criticized for promoting sprawl and the
degradation of farmland. Large-lot zoning essentially converts farms and valued open
space into private property and large lawns, where little community open space is
preserved, and neighbors are isolated from each other by their islands of unproductive
private land. The resulting pattern becomes "wall- to-wall" subdivision, where every
portion of each parcel is developed into yards, roads, and driveways.
39 Many propertyowners object to large lot zoning because, they allege, “low- and moderate-income
homebuyers are excluded from this sector of the housing market”.
40 Some critics havedubbed large lot zoning “snob zoning”.
413. Cluster Zoning
Cluster zoning utilizes development on part of a property while preserving the
remainder for open space and/or agricultural uses. Cluster zoning requires more
creativity in urban site design and protects on-site amenities or environmentally sensitive
areas.
42 Cluster zoning is also known as “open space zoning” or “density zoning,” andcluster subdivisions are sometimes known as “cluster developments”, “open space” or
“open land subdivisions”.
43 Cluster zoning may allow variable lot sizes, setbacks,landscaping, densities, and design standards.
Clustering may be accomplished by the use of a particular zoning district that
establishes a fixed or sliding scale area-based dwelling unit allocation and requires
clustering on a portion of the site. Clustering can be used in conjunction with existing
zoning and allowed as an optional or density bonus.
44 For example, in the Hammocks, aclustered residential development in Florida, single-family housing was built by creating
green spaces within neighborhoods and a greenway system between the neighborhoods
37
METROPOLITAN MIAMI-DADE COUNTY PLANNING DEPARTMENT , supra note 31, at 73.38
TOM DANIELS, WHEN CITY AND COUNTY COLLIDE: MANAGING GROWTH IN THE METROPOLITAN FRINGE217 (Island Press 1999).
39
Jackson Meadow, Ecology of the Cluster Model, available athttp://www.jacksonmeadow.com/brochure/brochure/brochure_3.htm
(August 1, 2002).40
The Greenbelt Education Project, How to Keep the Country in the Lowcountry, available athttp://www.charleston.net/org/greenbelt/tools.html
(August 1, 2002).41
Executive Order 418 Housing Certification Commonwealth Of Massachusetts Fy2002, available athttp://www2.massdhcd.com/e418portal/ CommReport02.asp?MNO=317&FY=2002 (August 2, 2002).
42
METROPOLITAN MIAMI-DADE COUNTY PLANNING DEPARTMENT , supra note 31, at 77.43
AMERICAN FARMLAND TRUST , supra note 30, at 33.44
METROPOLITAN MIAMI-DADE COUNTY PLANNING DEPARTMENT supra note 31, at 77.Miami-Dade County Agriculture and Rural Area Study
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and lakes. The Hammocks was also able to double their gross density to an average net
density of 11.5 units per acre.
45Cluster zoning may require the landowner of a tract of land to identify the
building lots and the open space to be preserved, or it may simply require that a certain
percentage of land remain as open space dedicated to agricultural uses. The protected
land is usually owned and maintained by a homeowners association. Permitted land uses
are either identified in the existing zoning or limited by cluster development regulations.
For example, one model ordinance permits residential uses such as clustered single
family houses, single family farmstead dwellings, and community living arrangements
and agricultural/open space uses such as farming (i.e. crops, farming, and livestock),
Christmas tree farming and sales, and passive recreational spaces (i.e. wildlife sanctuaries
and nature preserves).
46 Other communities, like Larimer County, Colorado, offer asystem of incentives and benefits that gives local administrators and land owners
flexibility to tailor land use requirements to the particularities of individual parcels of
property.
47However, the most effective clustering ordinances are those that are mandatory.
48When clustering and open space preservation are left optional, few developers take
advantage of the approach. Most continue as they have always done: creating
checkerboards of house lots and streets. This means that even though the clustering
option is in the zoning ordinance, it remains essentially unused. The community is still
left with conventional development patterns which destroy agricultural areas.
49Though cluster zoning can keep land available for agriculture or open space, it is
generally not a viable technique for commercial agriculture.
50 The protected land isgenerally owned by a homeowners association, and while homeowners may lease it back
to local farmers, some residents may object to allowing agricultural production because
of noise, dust, and odors related to commercial farming.
51 Utilization of right-to-farmlaws (discussed below) will help. One solution creates an ordinance that requires
homeowners to lease the land back to local farmers, while limiting the type and scale of
agriculture on the property, or ensuring that farmers who sell development rights to
homeowners retain title to continue farming.
52 In general, cluster zoning has been usedmost successfully to preserve open space or to create transitional areas between farms
and residential areas.
5345
Sprawlwatch, Land Use Planning and Zoning, available athttp://www.sprawlwatch.org/landuseandplanning.html
(August 1, 2002).46
Southeastern Wisconsin Regional Planning Commission, Model Zoning Ordinance for Rural ClusterDevelopment
, available at http://www.sewrpc.org/modelordinances/cluster_ordinance.pdf (August 1,2002).
47
E. Tyson Smith & Philip Moffat, An Analysis of the Development and Planning Alternatives to Protectthe Character of Eastern Sarasota County while Minimizing Adverse Impacts on Taxpayers
32 (January2000) (unpublished manuscript, on file with the University of Florida Conservation Clinic).
48
Id. at 32 (referencing SAMUEL N. STOKES, ET AL., SAVING AMERICA’S COUNTRYSIDE 182 (2nd Ed. 1997)).49
Randall Arendt, “Open Space” Zoning: What it is and Why it Works, 5 PLAN. COMMISSION J. 4 (1992),available at
(http://www.plannersweb.com/articles/are015.html#mandatory) (August 2, 2002).50
AMERICAN FARMLAND TRUST , supra note 30 at 33.51
Id.52
Smith, supra note 47, at 31.53
AMERICAN FARMLAND TRUST , supra note 30 at 33.Miami-Dade County Agriculture and Rural Area Study
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Critics of cluster zoning argue that it actually results in “clustered sprawl”.
54Critics also argue that cluster zoning is environmentally unsound because cluster
development works best with urban infrastructure, but the remote location requires onsite
septic tanks. Failing septic systems require the extension of water and sewer lines,
which opens farmland up to more development.
55 Finally, cluster development sometimesis criticized based on the simple presumption that residential and agricultural uses cannot
exist in close proximity without unacceptable conflict.
56 Clearly, as mentioned above,certain conflicts must be addressed. Crop dusting and spraying, for example, require that
significant buffers between crops and clustered homes be maintained.
Critics of clustering worry that this technique will cause loss of rural character.
However, subdivisions designed with this concern in mind can mitigate, if not eliminate,
this concern. For example, instead of having separate driveways onto the arterial roads,
creating a more urban feel, a subdivision could be designed so the entire tract is set back
from the main road, and only one access point exists to the road, with houses accessing a
loop or networks of small streets. Those streets should be gravel and narrower than
traditional urban subdivisions to create a rural neighborhood feel.
Subdivisions also should be buffered from the street with extensive landscape
material; perhaps so well-buffered that passing motorists are not aware that the houses
exist. If there are wooded or heavily landscaped areas, the cluster should locate within
the wooded areas
The design of the building within the community can also reduce any concerns.
Houses can be designed to connote a small town feeling instead of the spreading suburbs.
Architects may design homes with human proportions, local architectural styles, local
materials, and other techniques to connect the house to the particular community.
57Clustered developments are allowed in Miami-Dade County under its Zoning
Code.
58 Cluster developments must be single-family dwelling units and common areasare allowed within the zone, including any associated structures.
4. Buffering
Buffering is the physical separation of farms from incompatible uses, usually by
landscape, open space, or other barriers. Buffers are narrow bands of land planted with
permanent vegetation that are located around and in areas of intensive agricultural
production.
59 Buffers help safeguard farms from trespassers and protect adjacent54
DANIELS, supra note 38, at 219.55
Id.56
Id. at 219.57
RANDALL ARENDT ET AL., RURAL BY DESIGN: MAINTAINING SMALL TOWN CHARACTER 62 (PlannersPress 1994).
58
MIAMI-DADE COUNTY ORDINANCES 33-284.6-.9.59
National Conservation Buffer Council, Conservation Buffers: Showing Stewardship, ProtectingProductivity
, available at http://www.buffercouncil.org/ (August 1, 2002).Miami-Dade County Agriculture and Rural Area Study
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homeowners from the externalities of commercial farming.
60 Field borders, grass buffers,contour grass strips, grassed waterways, and vegetative borders, are several types of
buffers which serve to minimize conflicts between residential and agricultural users.
61Buffers are advantageous for many other reasons. Buffers create havens for
wildlife. Buffers are visible, tangible examples of land stewardship.
62 Buffers enhancequality of life by providing open space in a community and enhancing the value of land
conservation. Environmentally, buffers slow down water runoff from fields and block
suspended chemicals, pathogens, and sediment from reaching water bodies.
63Buffering places the responsibility for construction and maintenance upon the
farm owner, the adjacent homeowners or a third party. The Georgia Model Code, for
example, requires any non-agricultural use locating next to an agricultural use to provide
a 150 foot agricultural buffer.
64 The buffer must consist of trees, hedges, landscaping,and naturally occurring elements as long as there is a semi-opaque screen between the
agricultural and non-agricultural uses.
65 Many California localities similarly requireagricultural setbacks. In San Luis Obispo County the buffer is mandatory and ranges
from 100 to 800 feet depending on the type of agricultural use to be protected. In
Sacramento County the buffer is mandatory and generally requires a physical separation
of 300 to 500 feet. In Stanislaus County the buffer is mandatory and can be
topographical, vegetative or other and is determined on a site-by-site basis.
66Some buffers are not mandatory but are farmer initiated. In Suffield, Connecticut
an individual farmer may request a buffer with a width of 30 to 100 feet. The buffer is
located on the parcel to be developed and maintained by the developer. The law also
requires that lot owners be notified that they are responsible for buffer maintenance and
that subdivision plans include a provision for active agriculture and recognize agricultural
practices that may annoy or irritate residents.
67The Natural Resources Conservation Service (NRCS), of the United State
Department of Agriculture (USDA), promotes the development of buffers by farmers
themselves. The NRCS leads the National Conservation Buffer Initiative, a multiyear
effort undertaken by the USDA. The goal of the initiative is to encourage the use of
conservation buffers by farmers, ranchers, and other landowners as a means of improving
soil, water, and air quality while enhancing fish and wildlife habitat, and adding to the
60
AMERICAN FARMLAND TRUST , supra note 30, at 318.61
National Conservation Buffer Council, Conservation Buffers: Showing Stewardship, ProtectingProductivity, available at
http://www.buffercouncil.org/ (August 1, 2002).62
Id.63
Id.64
Georgia Department of Community Affairs, Model Code: Alternatives to Conventional Zoning:Agricultural and Buffer Requirements §4-3 (April 2002),
available athttp://www.dca.state.ga.us/planning/ModelCode/4-3AgriculturalBuffer.pdf
(August 1, 2002).65
Id.66
Farmland Preservation Report, Farmland Programs Neglect Buffer Protections, Volume12, Number 4,(February 2002).
67
Id.Miami-Dade County Agriculture and Rural Area Study
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beauty and diversity of farms and ranches across the country.
68 Farmers can receiveassistance through the Conservation Reserve Program and other federal, state, and local
government programs to help with the cost of implementing buffer practices. These other
programs include the Environmental Quality Incentives Program, Wildlife Habitat
Incentives Program, Wetlands Reserve Program, and Stewardship Incentive Program.
69A significant challenge with buffers is enforcement. Though ordinances may
require buffers, they are not always enforced. Buffering ordinances can be effective as
long as local government has subdivision review authority to impose the buffer
requirement and that they are enforced once in place. Placing the buffer restriction in the
landowner’s title will assure adequate legal notice to the individual land owner
responsible.
70Successful buffer ordinances cannot be standard; each buffer must be site based
and locally determined. A draft report from a California research group indicates that in
some cases structural barriers are actually more effective than swathes of open space.
Under this scenario, an ordinance must determine the structural barrier and establish a
source of payment for repairs and maintenance
715. Overall Benefits and Drawbacks of Agricultural Zoning
Overall, the aforementioned zoning techniques are an inexpensive way to protect
large areas of agricultural land because little public expenditure is necessary to
implement zoning ordinances. Communities also favor agricultural zoning ordinances
because they are easy and quick to implement as compared to TDR or PDR programs
(discussed below) and easy to explain to the public who are accustomed to zoning
ordinances. They also separate farms from non-agricultural land uses, and reduce the
likelihood of conflicts between farmers and non- farming neighbors. Finally, agricultural
zoning is flexible in that it can change wit h the economic or political climate.
72Critics of agricultural zoning suggest that such programs are not permanent.
While flexibility may be a benefit it is also a drawback because large agricultural parcels
may quickly be converted to developable parcels. Similarly, agricultural preservation
ordinances do not prevent annexation by municipalities (unless annexation is forbidden
on agricultural lands). Many successful agricultural zoning programs have a mandatory
deed restriction or easement requirement to prevent conversion when annexation occurs.
These ordinances also generally decrease land values, which decreases a farmer’s equity
in land. For this reason, many farmers oppose these programs. Finally, such programs
may be difficult to monitor and enforce on a day-to-day basis.
7368
United State Department of Agriculture, Farm Preservation Report: Buffers, Common-SenseConservation, available at
http://www.nrcs.usda.gov/feature/buffers/BufrsPub.html#InitiativeBuff_7Anchor
(August 1, 2002).69
Id.70
Farmland Preservation Report, supra note 66, at 2.71
Id. at 3.72
AMERICAN FARMLAND TRUST , supra note 30, at 50.73
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B. Non-Zoning Techniques
1. Right-to-farm Laws
Since 1963, every state in the nation has enacted a right-to-farm law.
74 Right-tofarmlaws are state laws or local ordinances that protect farmers and farm operations from
public and private nuisance law suits.
75 The right-to-farm laws strengthen the legalposition of farmers against nuisance suits by their neighbors, and protect farmers from
anti-nuisance ordinances and unreasonable agricultural regulations.
76 Right-to- farm lawsdo not protect farmers from state and federal pollution and safety laws, but do underscore
the legitimacy of farm uses.
77State right-to- farm statutes can be broken into three groups. First,
general rightto-farm statutes provide that a farming operation cannot be declared a nuisance if it was
not a nuisance at the time the operation began.
78 This type of statute is also termed a“coming to the nuisance” statute. It gives farmers a legal defense from residents moving
to the area who claim to be harmed by the off-site impacts of agriculture.
79 The secondtype of statute protects specific types of agriculture such as the cultivation of land,
production of crops, and raising of poultry.
80 These types of statutes protect farmers fromunreasonable local regulations. The third type of statute protects farmers and food
companies from suits over food safety.
81 Florida’s Right-to-Farm Act, which applies inMiami- Dade County, is a general right-to- farm law.
Right-to-farm laws have not been extensively litigated, but this is likely to change
as the urban fringe creeps nearer to farmland and new residents file suits based on
trespass rather than based on nuisance.
82 Plaintiffs may still file a nuisance suit against afarmer regardless of the existence of right-to-farm laws. Though the plaintiff has a slim
chance of winning, the cost and aggravation of the suit may be detrimental to the farm.
83Thus, some statutes, for example Michigan, require plaintiffs to pay farmer’s costs in an
unsuccessful nuisance suit,
84 while states such as Delaware, Iowa, Kentucky, Missouri,New Mexico, South Dakota, and Wisconsin allow farmers to recover only for frivolous
suits.
8574
Id. at 169.75
A public nuisance involves actions that injure the public at large, while private nuisances interfere withan individual’s use of their property.
76
AMERICAN FARMLAND TRUST , supra note 30, at 169.77
DANIELS, supra note 38, at 220.78
DAVID L. CALLIES, ROBERT H. FREILICH, & THOMAS E. ROBERTS, CASES AND MATERIALS ON LAND USE662 (3
rd ed. 1999).79
DANIELS, supra note 38, at 175 (citing NEIL HAMILTON, A LIVESTOCK PRODUCER’S LEGAL GUIDE TON
UISANCE, LAND USE CONTROL AND ENVIRONMENTAL LAW (Drake University Agricultural Law Center1992)).
80
FREILICH, supra note 29, at 287.81
Id.; Melody Petersen, Farmers’ Right to Sue Grows, Raising Debate on Food Safety, N.Y. Times, June 1,1999 at A-1, col. 1.
82
DANIELS, supra note 38, at 150.83
Id. at 151.84
Id.85
Id. at 176-79.Miami-Dade County Agriculture and Rural Area Study
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Right-to-farm laws are effective when metropolitan areas begin to encroach on
outlying farm communities.
86 They make urban dwellers that want a rural lifestylerethink their decision when animal waste, airborne pollution, odors, slow-moving farm
machines on roads, and roosters crowing at the crack of dawn disturb their “rural
tranquility”.
87 Without such laws, public law nuisance suits may succeed. As a politicalmatter these ordinances also encourage elected officials to minimize ordinances that are
intrusive on farming. Nonetheless, these laws do not prevent the ultimate problem of
incompatibility of uses, which must be addressed through strict environmental
enforcement and well-designed agricultural districts. Another resolution is to allow for
payment of damages instead of cessation of activities.
88One County Commissioner in Larimer County, Colorado suggested a creative
“right-to- farm” provision. He drafted the
Code of the West, which provides advice forpeople thinking of buying land in the rural part of Larimer County’s metropolitan region.
The introduction says:
It is important for you to know that life in the country is different from life in the
city. County governments are not able to provide the same level of service that
city governments provide. To that end, we are providing you with the following
information to help you make an educated and informed decision about whether
to purchase rural land.
89The
Code of the West then goes on to describe the realities of country life,including slow tractors, that some lots are not buildable, that farmers work around the
clock and that animals and manure can cause objectionable odors.
90Right-to-farm laws strengthen growth management techniques such as clustering.
In a recent case,
Whitted v. Canyon County Board of Commissioners,91 the Iowa SupremeCourt concluded that right-to-farm laws encourage full and complete use of agricultural
land, yet are still compatible with growth management techniques. A farmer proposed a
small subdivision on a portion of his farm with rocky, poor farmland. He intended to
continue farming the rest of the land. Neighbors appealed the approval of the subdivision
claiming it would deprive them of full use of their agricultural land. The court disagreed
and concurred with the county’s land use board, stating “[by] allowing development…the
development pressure on land more conducive to agriculture would be lessened.
Further…requiring deed restrictions and marketing disclosures would aid in preserving
the agricultural nature of the surrounding area.”
92Section 33-28.1 of the Miami-Dade County Zoning Code requires agricultural
disclosures for any land that is either designated Agriculture (AU), or zoned Interim (GU)
(outside UDB only) and determined to be subject to AU trends of development or located
within the UDB and abuts any AU zoned parcel. The seller of such property must inform
86
FREILICH, supra note 29, at 287.87
Id.88
See e.g. Boomer v. Atlantic Cement Co., Inc., 40 N.Y.S.2d 97 (N.Y.Sup. 1972).89
DANIELS, supra note 38, at 275.90
Id. at 275-78.91
44 P.3d 1173 (Idaho 2002).92
Id. at 1178.Miami-Dade County Agriculture and Rural Area Study
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the buyer that the land or adjacent land is zoned agricultural and that there are associated
noises, pollutants, and activities that might be offensive to the buyer.
The Florida Right-to-Farm-Act prohibits farms in operation for a year or more
from being declared either a public or private nuisance, except under very limited
circumstances. In order to enjoy protection under the Act, however, the farm must
continue to comply with “generally accepted agricultural and management practices”.
93The Second District Court of Appeals for the State of Florida found that the right-to-farm
law was “intended to preserve productive land for agricultural purposes and to protect the
established farmer from demands of sprawling urban development.”
94 However, verylittle litigation has occurred pursuant to this law since its original adoption in 1979.
2. Agricultural Districting
Agricultural districting is different than agricultural zoning. Zoning only
addresses particular land uses and is one tool that can be used in an agricultural district.
Agricultural districting, on the other hand, allows farmers to form special areas
where commercial agriculture is encouraged and protected, establishing a broad array of
measures to encourage and protect agricultural activity in the district.
95 Protectivemeasures may include bans on local government laws that restrict farming, enhanced
protection from private nuisance lawsuits, eligibility for differential tax assessment,
limiting non-farm development around active agricultural areas and conservation
easement programs.
96 Pennsylvania created one of the most effective agriculturaldistricting programs in the country. The Pennsylvania law identifies five purposes for
agricultural districting: “(1) Encourage landowners to make a lo ng term commitment to
agriculture by offering them financial incentives and security of land use; (2) Protect
farms from incompatible uses; (3) Assure permanent conservation of agricultural land to
protect the agricultural economy; (4) Provide compensation to landowners for
development rights; and (5) Leverage state funds for the purchase of agricultural
conservation easements and protects [sic] the public investment in easements.”
97Agricultural districting programs are generally state-level programs. To date,
sixteen states have enacted agricultural district laws.
98 Generally, state statutes establish aprocess for identifying agricultural districts and designate geographical areas for long
term agriculture. State statutes also include a combination of measures and management
tools, as described above, to protect farmland. The requirements and provisions of the
programs differ greatly, but general conclusions can be drawn. The programs are flexible
and local in nature, stabilize the land base at a low public cost, provide multiple benefits
93
Fla. Stat. 823.14.94
Pasco County v. Tampa Farm Service, Inc., 573 So. 2d 909 (2nd DCA 1990).95
AMERICAN FARMLAND TRUST, supra note 30, at 197; METROPOLITAN MIAMI-DADE COUNTY PLANNINGD
EPARTMENT , supra note 31, at 94.96
Id.97
AMERICAN FARMLAND TRUST , supra note 30, at 201.98
Id. at 197.Miami-Dade County Agriculture and Rural Area Study
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to farmers, help protect large blocks of land, and enrollment is voluntary.
99 In contrast,drawbacks associated with agricultural districting include the fact that sanctions for
withdrawing land are minimal and do not deter conversion; the limits on non-farm
development may not prohibit the development of urban infrastructure in agricultural
areas; in some states, the benefits are not a strong enough incentive for farmers to enroll;
and, in others, the procedure for creating the districts is long and cumbersome.
100 Floridadoes not have a similar state law, but that does not preclude Miami-Dade County from
implementing some agricultural districting measures typical in state- level programs.
New York has one of the most successful agricultural districting programs in the
nation, in part because it is aimed at preserving farmland through maintaining and
fostering farming itself. By granting a series of benefits that provide more favorable
social and economic conditions, the program encourages an environment that is more
beneficial for agriculture. Support from elected officials also has helped to create an
agriculture- friendly atmosphere. For example, the legislature passed an act that declares
agricultural land to be an “environmental resource of major importance”.
101In addition to creating an agricultural districting program, the New York program
also includes provisions that prohibit local nuisance ordinances from interfering with
normal farm operations; requires agency review of development which induces
infrastructure expansion; requires alternative consideration for public development
proposals that bring agricultural lands into the hands of the municipality through eminent
domain; allows for tax incentive programs; and directs all state agencies to maintain
viable agricultural districts.
1023. Land Evaluation Systems
The land evaluation and site assessment system (LESA) was launched in 1981 by
the U.S. Soil Conservation Service to make objective ratings of the agricultural suitability
of lands against demands for other uses.
103 LESA effectively rates a tract’s potential foragriculture, as well as other social and economic factors.
104 Though the federalgovernment developed LESA, state and local governments have adopted it to meet their
specific needs, and it has become part of many governments’ land use planning tools.
105LESA enables the planning of water, sewer, and transportation projects or the creation of
agricultural districts, and the assessment and review of environmental impacts.
10699
Shirley Sternamen & Elizabeth Mumby, New York State: Protecting Farming with Agricultural Districts77, 80,
in PLOWING THE URBAN FRINGE: AN ASSESSMENT OF ALTERNATIVE APPROACHES TO FARMLANDP
RESERVATION (Hal Hiemstra & Nancy Bush wick, eds., 1989).100
Id.101
Id. at 86.102
Id. at 80; see also N.Y. AGRI. & MKTS. LAW § 300 et. Seq. (1988 Cum. Supp.).103
Frederick R. Steiner, Introduction, in A DECADE WITH LESA: THE EVOLUTION OF LAND EVALUATIONAND
SITE ASSESSMENT 13 (Frederick R. Steiner, James R. Pease & Robert E. Coughlin eds., 1994).104
Id.105
Id.106
Lloyd E. Wright, The Development and Status of LESA, in A DECADE WITH LESA: THE EVOLUTION OFL
AND EVALUATION AND SITE ASSESSMENT 36, supra note 103.Miami-Dade County Agriculture and Rural Area Study
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LESA’s land evaluation and site assessment elements form a two-part system that
assists in the implementation of the Farmland Protection Policy Act (FPPA), selecting
appropriate lands to be included in the program, and establishing minimum parcel sizes
for farm subdivisions in agricultural districts.
107 The land evaluation part of LESA isusually designed by the federal Soil Conservation Service (SCS) and local Soil and Water
Conservation Districts (SWCD), and implemented by a local committee generally
comprised of a district conservationist, a cooperative extension representative, SWCD
directors, farmers, planners, local agricultural officials, and others who have knowledge
of the land resources of the area.
108Local officials or a locally appointed site assessment committee usually design
the site assessment component.
109 Site assessment factors include parcel size; on-farminvestment; and characteristics external to the parcel of land, such as nearby land uses,
zoning, and other farmland protection measures.
110 A local committee may include localplanners, members of the planning commission, SWCD directors, a cooperative
extension representative, building industry representatives, recreational representatives,
public interest groups, concerned citizens, and other government representatives
interested in agricultural preservation.
111LESA is a flexible system, designed to accommodate differences among states,
counties, or areas. Specific systems should be based on existing knowledge of the area,
local soil surveys, land use plans, policies, and programs. LESA may be applied
consistently to all lands or on a case-by-case basis.
112 LESA may be used to accomplishthe following objectives:
113i. Select lands to be part of a TDR or PDR program;
ii. Implement the federal Farmland Protection Policy Act;
iii. Choose farm units to be included in agricultural preservation programs;
iv. Determine appropriate lot size for subdivisions in agricultural districts;
v. Plan water, sewer, and transportation projects or the creation of
agricultural districts;
vi. Determine the need for an agricultural preservation program and the types
of programs to be used;
vii. Assess and review environmental impacts; and
viii. Develop guidelines under which agricultural land conversion to nonagricultural
uses should be permitted.
A 1990-91 study identified 212 local and state governments in 31 states as active
or former users of LESA.
114 Of these 212 jurisdictions, 138 local and state governmentswere still using the system in 1994. Those who abandoned the sys tem found it too
107
FREILICH, supra note 29, at 286.108
WRIGHT, supra note 106, at 35.109
Id.110
Id.111
Id. at 35-36.112
Id. at 36.113
Id.114
Id. at 58 referencing Steiner, F., J Pease, R. Coughlin, J. Leach, C. Shaw, A. Sussman, and J. Pressley.Agricultural Land Evaluation and Site Assessment: Status of State and Local Programs
(The HerbergerCenter 1991).
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complicated or time consuming; some noted a lack of interest or support by landowners
or planners.
115 The unreliability may be attributed to technical problems with a particularLESA system, staffing inadequacies, or local political factors.
116 Seventy- nine percent ofrespondents were satisfied with the LESA system.
Miami-Dade County does not have a LESA program, but other counties in Florida
– Highlands, Marion, and Pasco, for example – have utilized LESA. Although soil
quality, a major factor under LESA, is not as relevant in Miami-Dade County, other
LESA criteria will be useful should the County adopt prioritization criteria to implement
the preferred development scenario.
C. Land Acquisition Programs
1. Conservation Easements
A conservation easement (or conservation restriction) is a voluntary legal
agreement between a landowner and a land trust or government agency that permanently
limits uses of land in order to protect its conservation values. It allows a landowner to
continue to own and use their land and to sell it or pass it on to heirs.
117 Each easement istailored to meet the owner’s personal management objectives and goals for the property.
In essence the landowner sells his or her right to develop the land to a
conservation organization or governmental entity. Current uses, including residential and
recreational uses, agriculture, forestry, and ranching can continue, although the easement
might require the protection of some environmental and aesthetic qualities of the
property.
118Placing an easement may result in property tax savings and can be essential for
passing land on to the next generation. By removing the land's development potential,
the easement lowers its market value, which in turn lowers estate taxes. Whether the
easement is donated during life or by will, it can make a critical difference in the heirs'
ability to keep the land intact.
1192. Purchase of Development Rights
In a typical purchase of development rights (PDR) program, the government
purchases the owner’s right to develop specific parcels of land for managerial purposes,
leaving the owner all the rights of ownership.
120 One form of PDR commonly used foragricultural preservation is a purchase of conservation easements (PACE).
121 Landowners115
Id. at 59.116
Id.117
Land Trust Alliance, Conservation Options for Landowners: Conservation Easements, available athttp://www.lta.org/conserve/options.htm
(August 1, 2002).118
University of Florida, Conservation Easements, available athttp://www.sfrc.ufl.edu/Extension/ffws/ce.htm
(August 2, 2002).119
Id.120
See Thompson, Purchase of Development Rights: Ultimate Tool for Farmland Preservation?, 12Z
ONING & PLAN. L. REP. 153 (1989).121
The term PDR will encompass PACE for the remainder of this paper.Miami-Dade County Agriculture and Rural Area Study
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sell conservation easements to governments or other private conservation agencies. The
price of the development right is generally equal to the diminution in the market value of
the land resulting from the removal of the development rights, and thus is the difference
between the value of the land for agricultural use or open space and the land’s
development value.
122 In return for the payment, the landowner agrees to use the land foropen space or agriculture in perpetuity, though some programs allow termination of the
condition under certain restrictions.
123PDRs are designed to be voluntary. Offering an incentive to land owners may
convince them to resist selling their land for a potentially high price to subdivision
developers. In short, purchasing development rights is cheaper than buying the land in
fee simple.
State and local governments may cooperate on PDR programs or work
independently. Some states have enacted PDR programs that are funded, implemented,
and administered by state agencies. Other states fund the purchase of land by either local
governments or non-profit organizations.
124 Cooperative programs are advantageousbecause they allow the state to set broad policies and implement regional planning
strategies. Local governments, with their specific knowledge of the area, then identify
land suitable for the PDR program and monitor the land once the easements are in
place.
125 Cooperative programs generally increase the level of funding available forPDRs.
According to the American Farmland Trust, PDR programs are very popular with
farmers, yet the supply of money has lagged behind the supply of easements offered by
farmers. PDR programs are popular with farmers because they offer enticing incentives.
PDR programs increase the availability of real capital to farmers without mortgaging
land; lower real property taxes due to the decrease in the value of the land once the
development rights have been sold; and there are potential estate or inheritance tax
benefits.
126 PDR programs offer a more permanent solution than zoning and avoid thetakings challenges that hamper zoning efforts.
127On the downside, some landowners reject PDR programs because they are
perceived as “tying the hands” of the landowners’ heirs, who may wish to sell the land
for development value.
128 In addition, although buying development rights is cheaperthan buying the property outright, a PDR program is still cash intensive and communities
may reject PDR programs if they require local monetary support in the form of
development fees or taxes. In communities where taxes and fees are already levied for
schools, public safety, parks, infrastructure, and community programs, agricultural
122
FRANK SCHNIDMAN, MICHAEL SMILEY & ERIC G. WOODBURY, RETENTION OF LAND FOR AGRICULTURE:P
OLICY PRACTICE AND POTENTIAL IN NEW ENGLAND 18 (Lincoln Institute for Land Policy 1990).123
See, e.g., MASS. ADMIN. CODE Tit. 330 Section 22.10 or RI Gen Laws Section 42-82-5e.124
See, e.g.,: Frank Schnidman, supra note 122, Rhode Island 204-5, Vermont 141-43, Connecticut 186,Maine, 306 and Massachusetts 88-91.
125
Id.126
PATRICIA E. SALKIN, ZONING AND LAND USE CONTROLS § 56.04[2] (2000).127
DANIELS, supra note 38, at 223.128
SALKIN, supra note 126, at § 56.04[2].Miami-Dade County Agriculture and Rural Area Study
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preservation may fall by the wayside unless there is heightened community awareness of
the necessity of preserving agricultural lands.
129Successful PDR programs must be carefully designed and include a set of criteria
to determine from which lands the development rights should be purchased. The criteria
must take into account the location and surrounding uses of the land. PDR programs
make sense if hundreds of acres can be preserved (either through contiguous smaller
parcels or a few large parcels) because it makes it more likely that commercial farms will
be successful.
130 If only smaller amounts of farmland can be preserved, the adjacent landmay be a magnet for housing developers who market “rural lifestyles” and the conflict
between farming and residential uses will be maximized.
131 Additionally, the costs ofland in PDR programs must be reasonable and should be balanced against the likelihood
that land will remain in viable agricultural production for a certain amount of time.
132 Ata high expense per acre, little farmland will be saved at enormous costs, and even then
the aforementioned issue arises of whether the farm will be big enough to sustain itself.
133Although Miami-Dade County has a viable “transferable development rights”
program (discussed below), known as “severable use rights” it does not have a PDR
program. The advantages of a PDR program are that the governing agency – or a
designated land trust – has greater control over which lands are identified for
preservation. The challenge, of course, is generating the funds to purchase development
rights. However, in communities that are experiencing a decrease in agricultural viability
and simultaneous increase in urban growth pressure, the ability to affirmatively secure
open space is critical to success. As is discussed in Task 2(c), this has proven to be the
case in many communities around the country that have successfully preserved
significant agriculture and open space lands. The Task 2(c) report explores five of these
communities and suggests ways that Miami-Dade County might successfully implement
similar regulatory approaches.
3. Land Banking
Land banking, also referred to as advance acquisition, is a technique where land is
purchased before it is ready to be developed.
134 This requires the establishment of landbanks for the purpose of acquiring lands in urban areas where expansion is expected to
ensure that it is developed at the most advantageous time for the community.
135 The landbanks are governmental units that could either purchase agricultural land in fee simple
and lease it back to farmers or only purchase the development rights.
136129
RICK PRUETZ, SAVED BY DEVELOPMENT: PRESERVING ENVIRONMENTAL AREAS, FARMLAND ANDH
ISTORIC LANDMARKS WITH TRANSFER OF DEVELOPMENT RIGHTS 69 (Arje Press 1997).130
DANIELS, supra note 38, at 224.131
Id.132
SALKIN, supra note 126, § 56.04[2].133
DANIELS, supra note 38, at 224; see also the discussion of Suffolk County in Task 2(c).134
DANIELS, supra note 38, at 171.135
FREILICH, supra note 29, at 290.136
FREILICH, supra note 5, at 42.Miami-Dade County Agriculture and Rural Area Study
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Land banks are advantageous because they allow for better control over timing
and type of development, and discourage land speculation and leapfrog development.
137Also, by giving public officials a more personal interest in property and its regulation, it
helps promote sounder planning practices such as unrestricted, flexible comprehensive
plans. A land bank is flexible because it controls the land being sold and bought.
138A successful land bank must have the power to purchase property and condemn
land.
139 A land bank should be granted the power to hold land for an indefinite amount oftime so that the land bank can pace development appropriately. A land bank must also
have the power to borrow money, issue bonds, and obtain government aid.
140 The majordrawback to this technique is the expense.
The legality of land banking has been questioned, and the U. S. Supreme Court
has not established a bright line rule.
141 Both state and federal courts have declared that ifthe purpose of condemning the land has a reasonable relationship to the purpose of
protecting open space and environmental lands, then the taking is for a public use and
legitimate.
142 Land banking is more likely to be upheld by courts than other planningcontrols because it is a reasonable means of fulfilling a public purpose, particularly where
purchases are made consistent with the explicit policies of an adopted comprehensive
plan.
4. Transfer of Development Rights
Transfer of development rights (TDR) programs – called “Severable Use Rights”
in Miami-Dade – allow for planning on an area wide basis by allowing landowners in
restricted areas (“sending areas”) to transfer densities and other development rights to
landowners in areas appropriate for higher density development (“receiving areas”).
143Landowners in receiving zones are allowed to develop their land but only if they
purchase development rights from designated sending areas. Thus, development is
directed away from agricultural or environmentally sensitive lands to areas better
equipped to deal with heavy development.
144 TDR programs give governments analternative to purchasing land outright and ameliorate the harshness of restrictive
zoning.
145TDR programs are popular with citizens and governments because the goal is to
have an “everyone wins” outcome.
146 The sending site landowner is able to continuefarming without development pressures but with the benefits from the sale of the rights.
137
DANIELS, supra note 38 at 171.138
FREILICH, supra note 29, at 291.139
Id.140
Id.141
Id. at 292.142
Id.143
Id at 288.144
Andrew J. Miller, Transferable Development Rights in the Constitutional Landscape: Has Penn CentralFailed to Weather the Storm?
39 Nat. Resources J. 459, 467.145
FREILICH, supra note 29, at 288.146
PRUETZ, supra note 129, at 3.Miami-Dade County Agriculture and Rural Area Study
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The receiving site landowner is able to build at a greater density, and realizes the market
value of their land. The community benefits by preserving farmland without incurring
significant expense.
147 Local governments particularly find these programs attractivebecause:
148·
They encourage increased densities in developed areas making full use of publicinfrastructure;
·
Increased density works together with the need to provide a fair share ofaffordable housing;
·
Often, private developers pay landowners, so no public monies are spent;·
Landowners receive compensation for the restrictions placed on their lands, thusdecreasing the likelihood of successful taking claims; and
·
Local government can preserve a significant amount of land while funnelinggrowth into desired areas.
TDR programs are a market-based tool, thus municipalities must be certain there is a
market for the development rights being bought and sold. A municipality must, through a
comprehensive planning process, determine how many development rights are to be
bought and sold and where. A TDR program must encourage sales that benefit the entire
community, not just a few select landowners.
149 The number of rights to be bought orsold should be based on ecological and populations concerns; the more sprawling the
community, the more rights are required.
150Successful TDR programs include the following:
·
Encouragement of sending area landowners to sell their development rightsthrough development restrictions, development constraints, and transfer ratios;
151·
Encouragement of receiving area landowners by allowing the highest densityappropriate, exemption from certain fees, and exemption from certain
development standards;
·
A clear separation between resource lands, existing development, and propertiesplanned for development;
152·
An active real estate market to ensure buying and selling of rights;153·
Fast, easy and certain TDR approvals, including certain costs, and a clear,discernible, and transparent process
154·
A TDR bank or revolving fund that can help set a floor price for TDRs155·
Provision of public staff for implementation;·
Monitoring of program performance; and·
A flexible program that can be refined as needed.TDR programs may be mandatory or voluntary. Mandatory programs are
designed to prevent fragmentation of farmland in a way that protects landowners’
147
Id.148
DANIELS, supra note 38, at 225.149
Id. at 51; FREILICH, supra note 29, at 289.150
FREILICH, supra note 29, at 289.151
PRUETZ, supra note 129, at 51.152
DANIELS, supra note 38, at 226.153
Id.154
PRUETZ, supra note 129, at 58.155
Id. at 61.Miami-Dade County Agriculture and Rural Area Study
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equity.
156 Mandatory programs often feature dual zones with the down zoning of asending area and the designation of a receiving area. Landowners in the sending zones
are not required to sell their development rights, but may as a method of receiving
compensation for the down zoning. Similarly, receiving area landowners must buy
development rights to recognize the full economic potential of their land.
157 Mandatorydevelopment restrictions may include virtual prohibition of non-farm development in
agricultural areas through zoning, large minimum lot size, or restrictive requirements for
infrastruc ture.
158 Local governments implementing mandatory programs must ensure thatadequate public facilities will be available in the receiving areas.
159Voluntary TDR programs allow landowners in sending areas to sell their
development rights to a party in a receiving area in lieu of development in the sending
area. There is no reduction in density in the sending area.
160 Landowners in sendingareas may choose to develop parts of their property and sell off development rights on
another part, but this may lead to a large number of rural residences amid farmlands.
161Voluntary programs may be more attractive to local governments because they are less
politically controversial.
Successful TDR programs use a revolving fund where purchased development
rights are sold on the open market and the funds are reinvested in the purchase of new
development rights that will be banked. Communities that invest funds in areas other
than the purchase of development rights jeopardize their TDR program because only a
finite amount of money is available to purchase development rights.
However implemented, TDR programs must be designed to withstand legal
challenges. First, as discussed above, a market for development rights is critical. The
market will dictate whether a sending area is appropriate for down zoning or whether
such down zoning would leave no economically viable use for those property owners.
Designation of sending and receiving districts may also generate significant debate
(density in the sending areas is low, while density in the receiving areas is too high).
Next, zoning or the right to build in the receiving area should not be so restrictive so as to
force purchase of development rights for any type of development. Failure to allow some
use by right in the receiving district might be challenged as a taking.
162The Miami-Dade Board of County Commissioners adopted the East Everglades
Ordinance in 1981 that declares the Everglades an area of critical significance and
implements land use regulations that allow the transfer of development rights. The
programs is referred to as a severable use rights (SUR) program, because the right to
develop is “severed” from the sending property and transferred to a receiving property
more appropriate for development. The Miami-Dade County SUR program identifies
156
AMERICAN FARMLAND TRUST , supra note 30, at 128.157
PRUETZ, supra note 129, at 128.158
DANIELS, supra note 38, at 226.159
PRUETZ, supra note 129, at 128.160
Id.161
DANIELS, supra note 38, at 226.162
SALKIN, supra note 126, at § 56.04[3]; for further discussion of legal issues see Juergensmeyer, supranote 27, and Miller,
supra note 144.Miami-Dade County Agriculture and Rural Area Study
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sending parcels within the East Everglades area and receiving parcels within the UDB.
The ratio for SURs varies from one SUR per five acres to one SUR per 40 acres.
The East Everglades Ordinance imposes strict environmental regulations within
the sending areas that include road standards and excavation limitations. As a result of
the environmental limitations and the density restrictions, landowners find it very
difficult and expensive to build in the East Everglades, providing incentives for them to
sell their development rights.
The receiving site may use the SURs to increase density, lot area, frontage, and
other development requirements on residential and commercial receiving sites in the
unincorporated parts of Miami-Dade County that are designated for urban development.
Sending zones are also eligible for a 10 percent reduction in the minimum lot size, a one
third reduction in the required front setback and an 18 percent increase in density.
Additional commercial floor area is allowed in commercial and office park zones.
Although initially of limited success, the success of the SUR program has
increased since 1995 because the Comprehensive Development Master Plan provides for
the use of SURs; the transfer ratios are high in certain areas; the ordinance has eighteen
different zones that can receive SURs; the administrative process is predictable and
uncomplicated; and the local government is supportive of the program. The Miami-Dade
County program is also successful because there is a substantial demand for additional
development in the area. Developers have found it cheaper to buy SURs than to buy
land. By the end of 1994, 213 SURs had been transferred to receiving sites.
1635. Florida Rural and Family Lands Protection Act
Passed by the Florida Legislature in 2001, the Rural and Family Lands Protection
Act (Act) allows the Department of Agriculture and Consumer Service (DACS) to protect
ranch and timber land by offering four options to willing land owners. DACS may:
·
Purchase traditional permanent conservation easements;·
Purchase less restrictive rural land protection easements;·
Purchase agricultural easements, which are 30 year restrictions on developmentand subdivision with an option for the government to buy the land; or
·
Pay farmers to improve wildlife habitat and water resources on their land under apermanent conservation easement.
While conservation easements are a familiar tool in Florida (see discussion above)
the Act is innovative in that it institutes options for varying degrees of restriction and
time parameters. It adds flexibility for both landowners and easement holders that was
not previously available. The Act is supported by the agricultural industry as a means to
keep family farms in business and realize value for their property while protecting the
property from subdivision and development.
While the Act passed in 2001, no funding has been set aside for the program. In
December of 2001, the DACS issued a legislative report that described the types of lands
163
PRUETZ, supra note 129, at 85.Miami-Dade County Agriculture and Rural Area Study
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that would receive priority under the program. However, the 2002 and 2003 Legislatures
failed to allocate funds to the program. DACS had requested approximately $10 million
to fund the project. If future legislatures fund the program, this Act will significantly
impact local rural programs around the state, including Miami-Dade County. Funding
from the state- level can radically augment local efforts to preserve open space and rural
lands.
164D. Taxation Programs
The disparity between the market value of agricultural land for agriculture and for
other uses increases the pressure on farmers to sell their farms.
165 To reduce thetemptation or need to sell many states have enacted legislation giving real property tax
deferments, preferences, or exemptions to the owners of agricultural or eligible land.
Besides agriculture, eligible uses might be open space or timber production. Tax
programs can be effective when used in tandem with other mechanisms. Though tax
incentives do reduce the tax pressure, they do not always reduce the development
pressure, as the capital gains for land development may still outweigh the property tax
incentive in some markets.
166The purpose of agricultural tax programs is to help farmers stay in business by
reducing their real property taxes; to treat farmers fairly by taxing farmland based on its
value for agriculture instead of its value for development; and to protect farmland by
easing the financial pressures that force some farmers to sell their land.
167 Tax programsare beneficial because they correct inequities in the tax system created by development
pressures and they help farmers stay in business. Tax programs, unfortunately, cannot
ensure long term protection of farmland, and are criticized when they inadvertently
provide a subsidy to real estate speculators who keep their land in agriculture pending
development.
1681. Differential Assessment
Differential tax programs provide incentives for landowners to keep their land in
agriculture by assessing agricultural lands at its current or farm value rather than its fair
market value.
169 Agricultural value represents what farmers would pay to buy land inlight of the net farm income they can expect to receive from it. Full market value
represents what a willing buyer would pay for the land.
170 Every state except forMichigan has a differential assessment program. There are three kinds of differential
assessment programs: preferential assessment, deferred taxation, and restrictive
agreements.
Preferential assessment is the least restrictive of the three types because it does
not impose penalties for converting land to non-eligible uses. The agricultural value is
164
See Lancaster County, Pennsylvania, Task 2(c) Report.165
Id. at 285.166
Id.167
DANIELS, supra note 38, at 147.168
Id. at 151.169
FREILICH, supra note 29, at 285.170
DANIELS, supra note 38, at 147.Miami-Dade County Agriculture and Rural Area Study
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multiplied by the local tax rate to determine the amount of real value tax due each year.
Farm buildings are generally taxed at their fair market value. These programs base
farmer’s tax bills on the agricultural value instead of the fair value as long as the lands
remain in agricultural use.
171The principle behind a deferred taxation program is that the tax on the market
value of the property is deferred until the property is developed. Deferred taxation
programs use the same process as preferential assessment programs to calculate property
taxes. The difference is that a tax is imposed on the landowner when the land is
converted to non-eligible uses or sold for development. Some states impose “rollback”
penalties that are calculated based on the sum of the tax benefits received, while other
states just require the landowner to pay a conversion tax.
172 Most states requirelandowners to renew their application for tax deferment each year.
The taxation programs are designed to target commercial agricultural land rather
than small farms used for recreation or land that is vacant pending development. To
achieve this goal landowners may be required to sign restrictive agreements (California)
or restrictive covenants (Georgia, Hawaii, New York and Pennsylvania). The restrictive
agreements must be signed as a condition precedent to the reassessment of the land for
agricultural purposes.
173 In Minnesota, this goal is achieved by having fairly restrictiveeligibility criteria whereby lots must be at least 10 acres, and meet an ownership and
production test. For the ownership test, the land must be the owner’s homestead or that
of a surviving spouse, child or sibling; the land must have been in possession of one of
the previously mentioned parties for seven years; or the land must be the homestead of a
shareholder in a family farm corporation. To be considered an eligible use the land must
be devoted to production of farm products for sale that provide at least 1/3 of the family’s
income, or yield at least $300 plus $10 per tillable acre in total income, including rent.
174The Florida Constitution provides for a differential assessment for agricultural
lands.
175 Whether or not land is considered agricultural land for tax assessment purposesdepends on the length of time the land has been utilized as agricultural land; the purchase
price paid; the size, as it relates to specific agricultural use; whether effort has been made
to care sufficiently and adequately for the land in accordance with accepted commercial
agricultural practices, including, without limitation, fertilizing, liming, tilling, mowing,
reforesting, and other accepted agricultural practices; whether such land is under lease
and, if so, the effective length, terms, and conditions of the lease; and such other factors
as may from time to time become applicable.
176 After land is qualified as agriculturalland, it is eligible for differential tax assessment.
2. Circuit Breaker Tax Relief Credits
Circuit breaker programs allow for farmers to take tax credits for part of their
local property tax bill. The cost of the tax credit is distributed among all the taxpayers in
171
Id. at 153.172
Id. at 154.173
FREILICH, supra note 29, at 286.174
DANIELS, supra note 38, at 154.175
FLA. CONST. ART 7 §4.176
FLA. STAT. CH. 193.461 (2002).Miami-Dade County Agriculture and Rural Area Study
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the state. A circuit breaker program depends on involvement at the state level. Only
Michigan, Wisconsin, New York and Iowa have instituted circuit breaker programs.
The New York program, adopted in 1996, provides farmers who earn at least 2/3
of their total household income from farming with relief from local school taxes levied on
agricultural land and buildings. Farmers receive a full credit for up to 250 acres of
farmland and a fifty percent credit for more than 250 acres. The amount of credit also
depends on a family’s income.
The other state programs operate similarly but also can require the farmer to sign
a restrictive agreement where the farmer promises not to build any non- farm structure for
ten years. In return, farmers are protected against taxes levied by local utilities and
receive credits against their state income taxes.
1773. Real Estate Transfer Taxes
Real estate transfer taxes are taxes on various property transactions such as the
transfer of property deeds and the transfer of a controlling ownership interest in entities
which own real property.
178 Many states, including Florida, charge the tax when a deedis recorded. State statutes generally spell out the conditions of the tax and for what
purposes the revenue may be used.
Real estate transfer taxes are frequently used for farmland preservation.
Maryland is the leading state using this type of tax through a ½ percent tax on the value
of all real estate transfers that is divided between parkland acquisition and farmland
protection.
179Florida’s real estate transfer tax, called the documentary stamp tax, is codified in
Chapter 201 of the Florida Statutes. The tax is primarily levied by the state and the
revenue is used for numerous purposes including the purchase of conservation lands
through Florida Forever and the Land Acquisition Trust Fund.
180 Counties may assessdocumentary stamp taxes in limited situations and only for the purpose of funding the
Housing Assistance Trust Fund.
181 Miami- Dade County is the only Florida county thathas imposed a documentary stamp tax.
182177
DANIELS, supra note 38, at 155-156.178
PETER M. FASS; MICHAEL E. SHAFF; DONALD B. ZIEF, REAL ESTATE INVESTMENT TRUSTS HANDBOOK§ 5:71 (2003).
179
AMERICAN FARMLAND TRUST, supra note 30, at 101; see also discussion of Montgomery County inTask 2(c).
180
FLA. STAT. CH. 201.15.181
FLA. STAT. CH. 201.031.182
MIAMI-DADE COUNTY ORDINANCES 29-7.Miami-Dade County Agriculture and Rural Area Study
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E. Funding Programs
1. Impact Fees
Impact fees are mandatory payments paid by developers or builders in return for
development approval. They are calculated to be the proportionate share of the capital
cost (e.g. roads, schools, sewer lines, or gutters) created by a new development.
183 Thecharges are generally levied by local governments but are not taxes because impact fees
constitute a single payment, unlike periodic payments of taxes. The costs of developing
infrastructure for a new development are charged at the time of development, reducing
the need of the city or county to rely on bonds,
184 and the community is not forced to paythe high costs of development on the urban fringe or in other areas without existing
infrastructure. Impact fees exist in some form or another in every state in the nation.
185The power to charge impact fees is derived from local government’s police
powers. While some states enact enabling legislation for impact fees, others, such as
Florida, simply delegate the power to local governments through home rule power.
While local governments have limited powers to impose taxes, they have broad powers to
regulate in order to protect the health, safety and welfare of the community. Courts have
upheld the legality of impact fees if such fees meet the rationale nexus test, which ensures
a rational relationship between the demands of new development and assessments against
it.
186 There are two prongs to the rational nexus test. First there must be a need for anadditional public facility (i.e. schools, public safety, sewers) created by the new
development and the fee must not exceed the cost of providing the facility. Second, the
property charged the fee must derive a roughly proportional benefit from the new
facility.
187 Impact fees that do not meet this test may be considered takings, entitling theproperty owner to monetary damages.
Impact fee programs must be carefully designed so the fees are reasonable, and
fairly and accurately reflect a new development’s fair share of the necessary facility.
188Local governments often use careful economic analysis and planning to determine impact
fees. “The most widely implemented and judicially upheld impact fees are based on data
which indicate desired level-of-service standards for a particular facility and calculate the
cost of maintaining those standards in light of the increased demands created by new
development.”
189 While impact fees have not traditionally been used as a direct tool toprotect agricultural land, they have been used as part of an overall growth management
policy.
183
Frank, James E. & Paul B. Downing, Patterns of Impact Fee Use, in DEVELOPMENT IMPACT FEES 3(Arthur C. Nelson ed. 1988).
184
Id. at 4.185
James C. Nicholas, Julian C. Juergensmeyer & Ellen Margrethe Basse, Perspectives Concerning the Useof Environmental Mitigation Fees as Incentives in Environmental Protection (Part I),
7 ENVTL. LIABILITY25, 28 (1999).
186
See Id. at 30; Jordan v Village of Menomonee Falls, 137 N.W. 2d 442 (Wis. 1965).187
James C. Nicholas, supra note 185, at 37; see also Sarasota County v. Sarasota Church of Christ, Inc.,667 So.2d 180, 183 (Fla.1995).
188
Nicholas, supra note 185, at 30-1.189
Id. at 31.Miami-Dade County Agriculture and Rural Area Study
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2. Environmental Mitigation Fees
A new type of impact fee is being proposed by environmental advocates called
environmental mitigation fees, one purpose of which may be agricultural preservation.
Environmental mitigation fees are a hybrid between impact fees and market based
environmental mitigation models. “The goal of environmental mitigation fees is to
harness market forces to make environmental protection profitable.”
190Traditionally, environmental pollution fees have been assessed on a case-by-case
basis.
191 Each individual development or polluting facility has been required to mitigateits own impact on its own site, or mitigate its impact through some regulatory means.
192The problem with this approach is that it may not meet comprehensive environmental
goals for the community because it is not based on a community wide plan.
An environmental mitigation fee requires long-range planning for environmental
goals. Agriculture and environmentally sensitive lands, critical habitat, endangered
species and other critical resources are identified early on. Then, the comprehensive plan
guides the assessment of impact of any development. “Government regulators would
determine the units of environmental impact associated with a new or existing project and
multiply the number of units by a price per unit.”
193 A developer would be charged basedon the formula and may choose (1) to pay and proceed with the project; (2) to reduce the
adverse impact and pay a reduced fee; or (3) to pay another firm to mitigate adverse
environmental impact elsewhere.
194 The money generated by the program could go intopreserving agricultural land through the purchase of development rights, a TDR program,
or other method discussed in this paper.
Although not a fee-based arrangement, in Miami-Dade, environmental impacts
are mitigated through regulatory mechanisms. Section 24-58 of the County Code
requires a permit for any development that alters County canal rights-of-way, mangrove
trees, tidal waters, submerged bay bottoms, wetlands, natural surface flows, or critical
groundwater sources. The environmental mitigation fee would be collected and used in
the protection of these same environmental resources.
3. Federal Programs
The United States Department of Agriculture (USDA) has a number of programs
to assist state and local governments and individual landowners with conservation. The
Food Security Act of 1985 created the Farmland Protection Program (FPP) which
provides funds to help purchase development rights to keep productive farmland in
agricultural uses.
195 This program was recently reauthorized and modified by the Farm190
James C. Nicholas, Julian C. Juergensmeyer & Ellen Margrethe Basse, Perspectives Concerning the Useof Environmental Mitigation Fees as Incentives in Environmental Protection (Part II),
7 ENVTL. LIABILITY69, 71 (1999).
191
Id.192
Id.193
Id.194
The third option might be similar to off site mitigation programs such as pollution trading and wetlandsmitigation programs. For more information see James C. Nicholas,
supra note 185.195
Pub. L. No. 99-198, 99 Stat. 354 (1985).Miami-Dade County Agriculture and Rural Area Study
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Security and Rural Investment Act of 2002.
196 The general purpose of the program is "toestablish and carry out a farmland protection program under which the Secretary shall
purchase conservation easements or other interests in eligible land… for the purpose of
protecting topsoil by limiting nonagricultural uses of the land."
197The program is administered through the Natural Resources Conservation Service
(NRCS), a division of the USDA. The NRCS provides technical and financial assistance
to state, tribal and local governments and non-governmental organizations that already
have farmland protection programs. Through the benefit of the FPP these governments
and organizations acquire easements and interests in land, while landowners agree to
develop and carry out a conservation plan on the land. A total of $30 million was
available in 2001 for the program.
States may cooperate with the federal government to devise creative funding
techniques for agricultural preservation. Martin County, Florida recently agreed to pay
for the speedy installation of water lines for a Superfund project that will bring clean
water to its residents. While a state’s portion of Superfund programs is usually only 10
percent, in exchange for Florida's payment of the full cost of the project, the federal
agency has agreed to give Florida a credit that can be used to offset the state's share of
future cleanups.
198 A similar program could be used for agricultural preservation or thefederal government might opt to give credit for farming programs as well as for clean up
programs.
F. Regulatory Techniques
1. Growth Tiers
Timing and sequencing deve lopment to coincide with the provision of public
facilities was first implemented in an innovative plan in Ramapo, New York and was
upheld by the courts in the landmark decision
Golden v. Planning Board of Town ofRamapo
.199 The basic idea is that all residential development must proceed in accordancewith the provision of adequate municipal facilities as established by a long-term
comprehensive and capital improvement program.
200 The importance of the Ramapoplan is the recognition of the fundamental constitutional principle that development on
the urban fringe can be controlled by linking the development with the planned extension
of capital improvements over a reasonable time.
A “tier” system utilizes the Ramapo principle by providing for the delineation of
functional areas within the region for the identification of goals and objectives and the
implementation of growth management techniques.
201 Generally five tiers are created.Tier I consists of the downtown area or urban core. Tier II consists of existing residential
areas within the urban area and older suburban areas. Tier III consists of the actively
196
Pub. L. No. 107-171, §2503, 116 Stat. 134, 267 (2002)197
Id. at 268.198
John Cushman Jr., Superfund Makes a Rare Deal with Florida, N.Y. TIMES, July 31, 2002, available athttp://www.nytimes.com/2002/07/31/politics/31SUPE.html
. (August 2, 2002).199
Golden v. Planning Board of Town of Ramapo, 334 N.Y.S. 2d 138 (N.Y. App. 1972).200
Freilich, supra note 5, at 34.201
Id. at 35.Miami-Dade County Agriculture and Rural Area Study
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development area. Tier IV is the rural and agricultural land that is inappropriate or
premature for development. Tier V incorporates environmental and agricultural zones
that warrant preservation or protection.
202 The number of tiers varies according to thecurrent and desired land use pattern within the urban area, but will be similar to the
system described above.
2. Concurrency Programs
Concurrency programs tie development approvals to level of service (LOS)
standards. LOS standards measure the ratio of public facility capacity to the need for the
facility. Such a program takes into account all demand for the facilities, including
existing demand as well as the additional population added by new development
proposals. An adopted LOS standard reflects a policy decision concerning the
appropriate equilibrium between population and public facilities that may be applied to
new development in the standard setting and review process, and to the public capital
budgeting process. LOS standards conveniently provide a benchmark for monitoring the
growth management system.
203Florida was the first state to introduce “concurrency” requirements; the Florida
Statutes specifically provide that, “[P]ublic facilities and services needed to support
development shall be concurrent with the impacts of such development.”
204 Therequirement is part of Florida’s Growth Management Act of 1985 that was enacted to
discourage urban sprawl, improve existing infrastructure to support infill and
redevelopment, and to discourage urban development of rural lands.
205Concurrency programs do not concentrate on one particular sector of a city or
county; they look at a community comprehensively to plan for the entire area. The result
is that growth occurs at a rate that is economically beneficial to the community and in a
manner that retains land values. The specific techniques discussed above should be
implemented within the framework of the comprehensive plan.
Miami-Dade County has a Service Concurrency Management Program. No
development order shall be issued where LOS standards for all public facilities will not
meet or exceed LOS standards or where such an order would result in a reduction of
services, except in certain circumstances, such as when the development is located in a
designated urban infill area.
202
Id.203
S. Mark White, Adequate Public Facilities Ordinances and Transportation Management 8. PAS Report465 (1996).
204
West’s Fla. Sta. Ann. Section 163.3177 (10)(h).205
See generally West’s Fla. Sta. Ann. Section 163.Miami-Dade County Agriculture and Rural Area Study
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3. Urban Service Boundaries
An urban service boundary (USB)
206 is a relatively simple technique forchanneling growth that involves designating an urban services area and a rural service
area. Planning studies designate the urban services areas, which are the most suitable to
the extension of municipal services such as streets, sewers, and water, and rural service
areas where development is restricted.
207 The municipality commits to providing urbanservices within the urban service area before going beyond it.
208 One of the mostimportant attributes of a USB is that it makes the development pattern predictable for
landowners and developers.
209There are generally four goals for a USB: (1) to make the most efficient use of
public tax money for infrastructure funding; (2) preservation of agricultural and
environmentally sensitive lands; (3) efficient provision of municipal services; and (4)
promotion of compact urban development.
210 The USB also preserves agricultural landvalues within the community.
The most challenging issue surrounding a USB is how and under what
circumstances the boundary should be moved.
211 The location of a USB significantlyimpacts how a community develops, and in the agricultural context, may determine what
agricultural land is given over to development and what land is preserved for farming.
Therefore, adjustments to a USB should only take place after deliberate planning
considerations, that take into account both urban and rural interests.
212 An effectiveboundary adjustment process should be “firm enough to provide predictability for longrange
planning, yet sufficiently flexible to respond to changed conditions.”
213 Somestates, such as Oregon, set out guidelines for adjusting boundaries. These guidelines
include compliance with a comprehensive plan, and the analysis of socio-economic
impacts on the community and the existence of intergovernmental agreements.
214Intergovernmental coordination is required to successfully implement a USB
program because most urban cores are associated with a municipality separate from the
unincorporated area of the county.
215 Intergovernmental agreements should define therole of each governmental entity involved and describe the process for boundary
adjustments.
Miami-Dade County’s Urban Development Boundary (UDB) is a USB. Details
of the Miami-Dade County UDB are provided above in Section II.
206
A USB is different from an urban growth boundary that identifies an urban core and designates certainuses appropriate. The focus is less on urban services than on uses such as siting of future development,
protection of natural lands and resources, and compact urban form.
See Smith, supra note 47 at 19.207
CALLIES, supra note 78, at 642.208
V. Gail Easley, Staying Inside the Lines 10 PAS Report 440 (1990).209
Smith, supra note 47, at 19.210
See Wash. St. Ann. § 36.70A. 110 (2003)211
Smith, supra note 47, at 20.212
Id. at 20.213
Easley, supra note 208, at 10.214
Id. at 4.215
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IV. E
CONOMICS AND THE LAWA. Economic Value of Land
Preventing sprawl may be the most effective method of preserving the economic
value of land in Miami-Dade County. A 1995 Bank of America report stated, “Growth
has helped fuel … an unparalleled economic and population boom and has enabled
millions … to realize the enduring dream of home ownership … but sprawl has created
enormous costs… Ironically, unchecked sprawl has shifted from an engine of … growth
to a force that now threatens to inhibit growth and degrade the quality of our life.”
Indeed, the public infrastructure gap is nearing $4 trillion. Such high costs for
infrastructure impede development of community services and inhibit the preservation of
open space and agricultural lands. If urban growth consumes agricultural land, and
government money is spent building infrastructure, then community services and existing
infrastructure suffer. One conservative critic notes that more flexible zoning codes
“would allow for more innovative development designs that accomplish conservation
goals and satisfy consumer demand for housing alternatives. Ensuring that development
covers its infrastructure expenses will allow the marketplace to operate freely and
efficiently.”
216Preserving the economic value of land in Miami-Dade County can be
accomplished by concentrating on four goals:
1. Economic development through the preservation of agriculture;
2. Clustering of new development outside the urban area to reduce sprawl
and reduce infrastructure costs;
3. Maintain the character outside of the urban area; and
4. Develop strategies that are legally defensible.
B. Legal Framework
The following is intended to give a very general overview of the legal issues that
arise when local governments in Florida undertake planning and plan implementation.
Further legal analyses should be undertaken to address any specific program or ordinance
considered by the County for adoption.
The authority of local government agencies to adopt land use and zoning
regulations is derived from a state’s police power authority. Generally, comprehensive
growth management programs include police power regulations such as a zoning
ordinance incorporating density standards. Governments have the authority to regulate
the activity or use of property in order to protect or to prevent harm to the public health,
safety and welfare.
217 Though there are limitations on a government’s police power, the216
Samuel R. Staley & Matthew Hisrich, True Smart Growth, The Buckeye Institute Newsletter (May2002),
available at http://www.rppi.org/opeds/ohiosmartgrowth052102.pdf (August 2, 2002).217
See Keystone Bituminous Coal Assoc. v. DeBenedictis, 107 S.Ct. 1232 (1987); Euclid v. Ambler RealtyCo
., 272 U.S. 365 (1926); and Goldblatt v. Town of Hempstead, 369 U.S. 590 (1962).Miami-Dade County Agriculture and Rural Area Study
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courts have recognized the need for plans to deal with critical issues such as urban
sprawl, declining land values, environmental degradation, a lack of open space, and
agricultural preservation.
218Nonetheless, there are several types of legal issues that must be considered.
Generally, (1) does the local government have authority or police powers; (2) does the
action advance a legitimate governmental purpose; (3) is the system applied equally to
persons and land without operating in a discriminatory manner; (4) are the governmental
regulations implemented such that there is no "taking" of private property without "just
compensation"; and (5) do the government regulations afford substantive and procedural
due process to persons affected?
The authority of Florida’s local governments to plan is undisputed, and in fact
mandated, by Florida’s Growth Management Act of 1985. The other issues are
considered under three major headings: takings, impact fees/mitigation fees and due
process.
1. Takings
The majority of legal challenges to land use regulations fall under the claim that
the regulations constitute a "taking" of private property without "just compensation".
219If the purpose is to protect the public welfare, government may limit use of property
through regulation without a finding that a taking has occurred under the Fifth and
Fourteenth Amendments of the U.S. Constitution.
220 However, once a regulation221 hasbeen deemed to effectuate a taking, monetary compensation may be required to be paid
222or the regulation voided. If the regulation
223 does not involve a physical or title taking,but is in the nature of amenity protection such as open space preservation, environmental
protection, or agriculture preservation, the standard used is a balancing test to determine
whether the benefit to the public is outweighed by the burden to the land owner. The test
has two prongs: (1) does the regulation substantially advance a legitimate state interest,
and (2) does it deny an owner economically viable use of land.
224218
Robert H. Freilich & Jason M. Divelbiss, The Public Interest is Vindicated, 31 URBAN L. 731, 734(1999).
219
The following analysis involves a discussion of federal takings jurisprudence, which is applicable inboth federal courts and state courts in Florida.
220
Keystone Bituminous Coal Assoc., supra note 217.221
Since the seminal case Penn. C. Transp. Co. v. N. Y. C. Landmarks Commn., 438 U.S. 104 (1978), theUnited States Supreme Court has recognized three kinds of regulatory takings: physical, title, and
economic. A physical taking is one where a governmental entity invades private property regardless of the
extent of diminution in property value.
See Kaiser Aetna v. U. S., 444 U.S. 164 (1979). A title or exactiontaking does not involve land invasion, but results from the government accepting a title dedication or
monetary exaction representing a payment in lieu of dedication.
See Nollan v. Ca. Costal Commn, 483 U.S.825 (1987) and
Dolan v. City of Tigard, 512 U.S. 374 (1994). An economic taking is one where aregulation does not substantially advance legitimate state interest and denies an owner of economically
viable use of his land.
See Agins v. City of Tiburon, 447 U.S. 255 (1980).222
First English Evangelical Church v. County of L. A., 107 S.Ct. 2378 (1987).223
Nollan, supra note 221.224
See, e.g. Agins supra note 221; Haw. Hous. Auth. v. Midkiff, 467 U.S. 229 (1984); and Lucas v. S. C.Costal Council
, 505 U.S. 1003 (1992).Miami-Dade County Agriculture and Rural Area Study
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Under the first prong, the court will not construe the governmental action to be a
taking as long as the governmental entity has reasonably concluded that “the health,
safety, morals, or general welfare would be promoted by prohibiting a particular
contemplated use of land.”
225 The courts also require that the regulation is reasonablycalculated to meet the evil without exceeding the public necessity or substantially
affecting uses that do not “partake of the offensive character of those which create the
problem sought to be ameliorated.”
226 In short, the government must craft regulations in amanner that is rationally- related to the legitimate purpose it seeks to advance.
Under the second prong, a court must determine whether the property maintains
any permanent beneficial value when viewed as a whole.
227 Both federal and state courtshave uniformly held that all substantial use of property must be lost before an economic
taking occurs. Economic takings must be viewed in their entirety, and therefore a
diminution in value of even 99 percent has not been viewed as a taking.
228TDR programs have been particularly susceptible to takings claims, but if the
TDR system is designed appropriately it will be upheld. The key to a successful program
is effectively protecting the sending area's resources while offering the property owner
fair and reasonable compensation. Florida courts have upheld TDR programs in
City ofHollywood v. Hollywood, Inc
229 and Glisson v. Alachua County.230In the Hollywoodcase, the court upheld a city zoning ordinance that restricted beachfront lots to singlefamily
dwellings and granted the owner TDRs that could be applied to adjacent lots to
increase permissible density. The purpose of the ordinance was to preserve the
beachfront property, and the court dramatically noted, “Before us is the last unspoiled
beach area on the Gold Coast, a veritable Shangri-La in an otherwise endless Himalayan
mountain range of cement to the south.”
231 In Glisson, the court upheld a TDR programdesigned to protect threatened wetlands. In both cases, the court found that protecting
open space and environmentally sensitive areas was a legitimate state interest.
2. Impact Fees/ Mitigation Fees
Although there is no specific case law on mitigation fees in Florida, a review of
the impact fees jurisprudence is relevant because any mitigation fee legal analysis should
follow the same arguments. In 1994, the U.S. Supreme Court decided the important case
of
Dolan v. City of Tigard232 holding that not only must exactions have the requirednexus to a development’s impacts (a matter settled in
Nollan v. California CoastalCommission
,),233 but also that the degree of the exaction must be “roughly proportional to225
Penn C. Transp. Co., supra note 221, at 125.226
Kirsch Holding Co. v. Borough of Manasquan, 59 N.J. 241, 281 A.2d 513, 518 (1971).227
See, e.g. Concrete Pipe and Products, Inc. v. Constr. Laborers Pension Trust, 508 U.S. 602, 643-44(1993);
Pennel v. City of San Jose, 485 U.S. 1 (1988); Hodel v. Irving, 481 U.S. 704 (1987).228
Concrete Pipe and Products, supra note 227; see also City of Monterey v. Del Monte Dunes, 119 S.Ct.1624 (1999).
229
432 So. 2d 1332 (Fla. Dist. Ct. App. 1983), review denied, 441 So. 2d 632 (Fla. 1983).230
588 So. 2d 1030 (Fla. Dist. Ct. App. 1990), review denied, 570 So. 2d 1304 (Fla. 1990).231
Hollywood, supra note 229, at 1337-388.232
Dolan, supra note 221.233
Nollan, supra note 221.Miami-Dade County Agriculture and Rural Area Study
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the projected impact of the proposed development.”
234 Local governments mustdemonstrate that exactions imposed as a condition of development are not only related in
nature, but also in extent, to the impact of the development paying the fee.
The Florida Supreme Court has upheld local government’s authority to impose
impact fees based on general home rule and police power theories. The Growth
Management Act specifically encourages the use of impact fees,
235 and Florida courtshave adopted the rational nexus test as the appropriate standard by which to measure their
validity.
236 However, just as other land development regulations can only be exercisedwithin the bounds of substantive due process, so too are impact fee impositions similarly
bound. The Florida Supreme Court has adopted
237 and reaffirmed238 the dual rationalstandard as the appropriate measure of whether a local government has exceeded its
constitutional authority in the imposition of impact fees. Based on this case law, it is
likely that mitigation fees would be upheld in Miami-Dade County.
3. Due Process
Many land use claims are based on the due process clause of the Fourteenth
Amendment. Procedural due process is not discussed here as individuals cannot bring
these suits against a government for a legislative action. Substantive due process imposes
a requirement that the land use regulations must promote a legitimate public end in a
rationale manner.
239 Legitimate state interests are often described in zoning laws in termsof the protection or furtherance of the public health, safety, morals, or general welfare. A
landowner may assert that the regulation is arbitrary and capricious, bearing no
substantial relation to the public health, safety, morals, or general welfare, and is
therefore an invalid exercise of the police power (an “arbitrary and capricious due
process” or “substantive due process” claim).
240 This standard is a heavy burden for alandowner to overcome.
241V. M
IAMI-DADE COUNTY – VALUE PRESERVATION PRINCIPLEThe following analysis presents a guiding principle for analyzing how the County
might develop a program that will retain the value of agricultural land while
simultaneously protecting open space and rural areas for future generations. Although
the final recommendation (Task 2(d)) will be presented in light of the development
scenarios outlined in Task 1(f), the Team, based on the extensive input of the Citizens’
Advisory Committee, has determined that the final recommendation – the “preferred
development scenario – should set forth a means of protects open space in perpetuity in a
234
Dolan, supra note 221, at 388.235
See FLA. STAT. ch. 163.3202(3) (2001).236
Home Builders & Contract Assocn. of Palm Beach County, Inc. v. Board of County Commissioners,446 So.2d 140 (Fla. 4th DCA 1983).
237
Contractors & Builders Assocn., Inc. v. City of Dunedin, 329 So.2d 314 (1976).238
St. Johns County v. Northeast Florida Builders Assocn., Inc. 583, So.2d 635 (Fla. 1991)239
CALLIES, supra note 78, at 349.240
Eide v. Sarasota County, 908 F.2d 716, 722 (Fla. 1990); Euclid supra note 217, at 395.241
Restigouche v. Jupiter, 59 F.3d 1208, 1214 (11th Cir. 1995) (applying same rational relationship test asin equal protection cases).
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manner that also protects the land investments made by property owners in the Study
Area. In order to meet the complex, and sometimes competing, goals of open space
preservation, a comprehensive program that includes any number of the agricultural
preservation techniques discussed in this paper - and more thoroughly in the Task 2(c)
report - may be employed. However, the Team recommends that the following principle
guide the ultimate recommendation:
Is there a regulatory balance that would provide a landowner a return on
his or her investment equal to or in excess of the reasonable return under
a suburban development alternative, while at the same time preserving
important open space and rural lands?
VI. C
ONCLUSIONThis Report is intended to inform the ongoing analysis being conducted by
the Citizens’ Advisory Committee and the various consultant Team members.
The background concepts set forth here will be refined in forthcoming reports and
analysis. Specifically, Task 2(c), “Analysis of Rural Land Uses,” describes how
five (5) communities from around the country have employed value-preservation
techniques – relying heavily on the concept of PDRs – to protect their threatened
agricultural economies and rural open space. In each case, these communities
have sought to protect the resource most critical to a viable agricultural economy
– the land. Furthermore, consistent with the guiding principle set forth in the
section above, each of these communities has done so by adopting funding
programs that ensure that the community at large, which benefits from the
preservation of this discrete area of the jurisdiction, shares in the burden of
agricultural preservation.
Abstract: Restoring the Urban Forest Ecosystem1
Mary L. Duryea, Eliana Kämpf Binelli, and Lawrence V. Korhnak, Editors
21. This document is the Abstract, Table of Contents, and Acknowledgments for SW-140, Restoring the Urban Forest Ecosystem, a CD-ROM (M.L. Duryea,
E. Kämpf Binelli, and L.V. Korhnak, Eds.) produced by the School of Forest Resources and Conservation, Florida Cooperative Extension Service,
Institute of Food and Agricultural Sciences, University of Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Mary L. Duryea, Professor and Extension Forester, Eliana Kämpf Binelli, Extension Forester, and Lawrence V. Korhnak, Senior Biological Scientist,
School of Forest Resources and Conservation, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, PO Box
110410, Gainesville, FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Restoring the Urban Forest
Ecosystem
The urban forest ecosystem can provide many
ecological services and benefits to cities and
communities including energy conservation,
contributing to global biodiversity, and maintaining
hydrologic and nutrient cycles. Yet in many
instances these benefits are not realized due to poor
health and management of the urban forest. Many
opportunities for restoration -- reestablishing the
structure and function of the urban forest ecosystem
-- exist. The goal of restoration is to return the urban
forest to a form which is more ecologically
sustainable. A restored urban forest will contribute
positively to the community instead of being a drain
on its resources. Many of our parks are composed of
trees and grass requiring intensive maintenance
inputs such as fertilizing, irrigating, mowing and
raking. With restoration these parks could take
advantage of natural processes such as nutrient and
water cycling, thereby saving money, energy and
resources for the community. Connecting these
restored parks to other ecosystems such as
waterways can also contribute to biodiversity and
wildlife conservation. Restoration sites can range
from backyards to neighborhoods to parks to whole
waterways and metropolitan areas. The United States
hosts an abundance of successful and innovative
urban forest restoration projects which illustrate the
potential for creativity, diversity and the ability to
tailor projects to local needs and opportunities. This
CD-ROM explains basic ecological principles for the
urban forest's water, soil, plant and animal
communities. It discusses problems common in the
urban forest such as aquatic eutrophication, soil
aeration, invasive plants and loss of biodiversity.
Solutions, strategies, examples, and additional
resources are presented to help make urban forest
restoration projects successful. Its goal is to inspire
the restoration of urban forest ecosystems which will,
in turn, restore and conserve our planet for future
generations.
Contents
Chapter 1: Restoring the Urban Forest
Ecosystem
- An Introduction - Mary L. DuryeaChapter 2: Basic Ecological Principles for
Restoration
- Mary L. Duryea, Eliana KämpfBinelli, and Henry L. Gholz
Abstract: Restoring the Urban Forest Ecosystem 2
Chapter 3: Biodiversity and the Restoration of the
Urban Forest Ecosystem
- Eliana Kämpf BinelliChapter 4: Plant Succession and Disturbances
in the Urban Forest Ecosystem
- Eliana KämpfBinelli, Henry L. Gholz, and Mary L. Duryea
Chapter 5: Developing a Restoration Plan
That Works
- William G. HubbardChapter 6: Restoring the Hydrological Cycle
in the Urban Forest Ecosystem
- Lawrence V.Korhnak
Chapter 7: Site Assessment and Soil
Improvement
- Kim D. CoderChapter 8: Enriching and Managing Urban
Forests for Wildlife
- Joseph M. SchaeferChapter 9: Invasive Plants and the
Restoration of the Urban Forest Ecosystem
-Hallie Dozier
Chapter 10: Glossary of Terms for Restoring
the Urban Forest Ecosystem
- Eliana KämpfBinelli, Mary L. Duryea, and Lawrence V. Korhnak
Acknowledgments
We are grateful for funding from the USDA
Forest Service, Cooperative Forestry through the
National Urban Community Forestry Advisory
Council's grants program. Special thanks to Suzanne
del Villar who patiently waited for all our reports.
We are also most grateful to Ed Macie, USDA Forest
Service, Region 8, Atlanta, who in addition to
supporting this CD-ROM has enthusiastically guided
and sponsored the Urban Forestry Institute for over
ten years.
At the University of Florida, we would like to
thank Wayne Smith for his continued encouragement
and support for this project. Also, many long hours
were spent by Howard Beck and Petraq Papajorgji of
IFAS Information Technologies they planned,
designed and successfully created this CD-ROM and
its printable version. They were assisted by Anna
Beck, Joe Bess and Rayna Elkins. Thank you all so
much.
We found many beautiful photos to describe
projects around the U.S. Everyone is credited with
each photo but we would like to extend our thanks to
all you photographers for your generosity in sharing
these beautiful scenes with us.
And finally, the authors also extend their sincere
gratitude to the many people around the U.S. who
shared information with us about their restoration
programs: Don Alam, Artesia, NM; Laurie Ames,
City of Seattle Dept. of Neighborhoods; Rob Buffler,
Greening the Great River Park, St. Paul, MN;
Charley Davis, Portland Parks and Recreation, OR;
Meridith Cornett, Minnesota Department of Natural
Resources; Sandy Diedrich, Forest Park Ivy Removal
Project, Portland, OR; Ray Emanuel, Drew Gardens,
NY, NY; Alice Ewen, American Forests,
Washington, DC; Steve Graham, City of Tampa
Parks Department, Tampa, FL; Steve Gubitti, Bill
Baggs Park Restoration, Department of
Environmental Protection, Tallahassee, FL; Paula
Hewitt, Open Road, NY, NY; Judy Okay, Difficult
Run Watershed Project, Virginia Department of
Forestry; Kit ONeill, Ravenna Creek Alliance,
Seattle, WA; John Rieger, Carmel Valley Restoration
and Enhancement Project, CA; Linda Robinson,
Naturescaping for Clean Rivers, Portland, OR; Joe
Schaefer, Schoolyard Ecosystems for Northeast
Florida, Gainesville, FL; Beth Stout, National
Wildlife Federation, Portland, OR; David M.
Wachtel, Chicago Wilderness; David J. Welsch,
USDA Forest Service, Northeastern Division,
Radnor, PA; Paul West, Seattle Dept. of Parks and
Recreation; and Greg Wolley, Metropolitan
Greenspaces, Metro, Portland, OR.
We dedicate this work to all the hard-working,
dedicated and creative people around the U.S. who
are finding so many ways to restore the beauty and
health to the urban forest ecosystem.
Chapter 1: Restoring the Urban Forest Ecosystem: An
Introduction1
Mary L. Duryea
21. This is Chapter 1 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Mary L. Duryea, Professor and Extension Forester, School of Resources and Conservation, Cooperative Extension Service, Institute of Food and
Agricultural Sciences, University of Florida, PO Box 110410, Gainesville, FL 32611
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Urban and community forests are often managed
as individual trees instead of whole forest
ecosystems. Cities inventory and manage these tree
species to meet many important needs such as energy
conservation, beauty, and recreation in the city. Yet,
there are many opportunities for urban forest
restoration to provide additional ecological benefits
such as storm-water management, wildlife
management, and biodiversity. Restoring the urban
forest ecosystem is reestablishing the ecological
health of the urban forest ecosystem. The goal of
restoration is to return the urban forest to a form
which is more ecologically sustainable for the
community; the restored urban forest will contribute
positively to the community instead of being a drain
on its resources. Many of our parks, for example, are
composed of trees and grass requiring intensive
maintenance inputs such as fertilizing, irrigating,
mowing and raking. With restoration these parks
could take advantage of natural processes such as
nutrient and water cycling, thereby saving money,
energy and resources for the community. Connecting
these restored parks to other ecosystems such as
waterways can also contribute to biodiversity and
wildlife management and conservation. The options
for restoration sites include: yards, vacant lots,
shopping centers, schoolyards, parks, industrial
parks, and waterways. The projects can be varied
such as: (1) The simple act of eliminating leaf-raking
in a park to reestablish the natural forest floor and the
natural cycling of nutrients; (2) The establishment of
understory plant species in a schoolyard to promote
wildlife; (3) The eradication of an invasive plant
species which is eliminating much of the understory
biodiversity in a park; (4) The re-design of a parking
lot to decrease stormwater runoff and provide a small
ecological wetland; or (5) The re-creation of a park
with species and ecosystems to be just the way it was
in the 1800s. The United States hosts an abundance
of successful and innovative urban forest restoration
projects. The two key ingredients that make these
projects so successful are the involvement of people
from the community and the formulation of a
restoration plan.
The Urban Forest Ecosystem
To define the urban forest ecosystem we take
the original definition of ecosystem and apply it to
the urban forest.
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 2
The urban forest ecosystem is a collection of
living organic matter (plants, animals, people,
insects, microbes, etc.) and dead organic matter
(lawn clippings, leaf-fall, branches) on a soil (with
all its urban characteristics) through which there is
cycling of chemicals and water and flow of energy.
When we think of the urban forest ecosystem we
can think of the whole city or community as one
ecosystem or we can focus in on a smaller parcel of
land as the urban forest ecosystem. The big picture,
bird's-eye-view is important to identify sites that
might need restoration (
Figure 1). For example, wemight see two parks that could be connected with a
greenway to benefit wildlife communities. Or we
might see an area of the city which is void of trees,
an urban heat island, that could be restored with a
tree canopy. Yet, we also need to look at the urban
forest ecosystem as smaller parcels of land such as
neighborhoods, parks, or schoolyards. At this level
we can see specific management alternatives and
specific ecological needs for each of these land units.
Figure 1.
When we think of the urban forest ecosystemwe can think of the whole city or community as one
ecosystem or we can focus in on a smaller parcel of land
(a park, schoolyard or industrial park, for example) as the
urban forest ecosystem. Photo by Hans Riekerk
What is "Restoring the Urban Forest
Ecosystem"?
Restoration has traditionally been defined as
reconstructing or repairing something, often a work
of art or ancient building. Ecologists have defined
ecological restoration to be:
• "The return of an ecosystem to a close
approximation of its condition prior to
disturbance." (National Research Council
1992)
• "The intentional alteration of a site to establish
a defined indigenous, historic ecosystem. The
goal of this process is to emulate the structure,
functioning, diversity and dynamics of the
specified ecosystem." (Society of Ecological
Restoration 1992)
• "Ecological restoration is the process of
renewing and maintaining ecosystem health."
(Society of Ecological Restoration 1995)
• "Ecological restoration is the process of
assisting the recovery and management of
ecological integrity. Ecological integrity
includes a critical range of variability in
biodiversity, ecological processes and structures,
regional and historical context, and sustainable
cultural practices. (Society of Ecological
Restoration 1996)
Most of these definitions center around the
recovery, repair or re-establishment of native
ecosystems. Because of the loss of species, the
increase in disturbances and several other factors,
exact restoration may be an impossible feat and
many people wish to call it rehabilitation.
Restoring the Urban Forest Ecosystem is
reestablishing the ecological health of the urban
forest ecosystem.
In urban forest ecosystems we have a very
different situation, and therefore we need to define
restoration differently. The urban forest is a mosaic
or patchwork of highly altered landscapes ranging
from street trees to neighborhoods with landscaping
to shopping centers to waterways to parks to
fragments of remaining native ecosystems. For this
CD-ROM and its series of publications we have
chosen to define restoration as reestablishing the
ecological health of the urban forest ecosystem.
More specifically, restoration means altering a site (a
park, waterway, neighborhood) to a state which is
more ecologically sustainable for the community or
city. Restoration might reestablish ecological
structure, functions, pathways, and/or cycles. A
restored site with its renewed or re-introduced
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 3
ecological attributes will contribute more positively
to the community instead of being a drain on its
resources.
Examples of potential sites and projects for
restoring the urban forest ecosystem include:
• The simple act of eliminating leaf-raking to
reestablish the natural forest floor and the
natural cycling of nutrients.
• The establishment of understory plant species
in a schoolyard to promote wildlife species.
• The eradication of an invasive plant species
which is eliminating much of the understory
biodiversity in a neighborhood.
• The clean-up of a vacant lot or site in a
neighborhood and the establishment of a park.
• The re-design of a parking lot to decrease
stormwater runoff and provide a small
ecological wetland.
• The re-creation of a park with the native
ecosystems that were present 100 years ago.
Potential sites for restoring the urban forest
ecosystem include (
Figures 2, 3, and 4):Figure 2.
A vacant or abandoned lot in an industrial areaof town.
Figure 3.
A small water-retention pond which could berestored with wetland species.
Figure 4.
A schoolyard.The Story of two parks
A description of two hypothetical parks offers
insights into the reasons and benefits of restoration.
Wilson Park
• Wilson Park has five baseball fields and four
basketball courts which are under constant use
by the community. (
Figure 5).• A monoculture of 60-year-old pine trees
surrounding the ball fields has swing sets and
picnic tables in its understory (
Figure 6). Lastyear when bark beetles invested loblolly pines in
nearby parks, plantations and natural areas, park
managers worried that they might lose this pine
forest to the beetle.
• When viewed closely we can see that not only
are there no understory plant species but the park
managers remove every leaf and twig that falls
to the ground (
Figure 7).• In another area of the park, managers work to
maintain a grass understory under several live
oaks (
Figure 8). With little light for grassgrowth, addition of fertilizers, water and
frequent mowing makes this an intensively
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 4
managed area for the park. Every leaf and
branch must also be removed in these hardwood
and grass forests.
Figure 5.
Wilson Park has several baseball fields and fourbasketball courts which are under constant use by the
community.
Figure 6.
A monoculture of 60-year-old pine treessurrounding the ball fields has swing sets and picnic tables
in its understory. Last year when bark beetles invested
loblolly pines in nearby parks, plantations, and natural
areas, park managers worried that they might lose this
pine forest to the beetle.
Figure 7.
When viewed closely we can see that not onlyare there no understory plant species but the park
managers remove every leaf and twig that falls to the
ground.
Figure 8.
In another area of the park, managers work tomaintain a grass understory under several live oaks. With
little light, addition of fertilizers, water and frequent mowing
makes this an intensively managed area for the park.
Every leaf and branch must also be removed in these
hardwood forests.
• A bird's-eye-view of another hardwood area
shows very little remaining on the ground
(
Figure 9). All leaves have been removed andthe resulting bare soil shows the exposed and
unprotected roots of shrubs and trees (
Figure10
).• This kind of management results in intensive
use of people and energy resources (
Figure 11).Often after the natural leaves and branches are
removed, landscape mulch is brought in to cover
the ground.
• One of the park managers has planted camelias
in one of the bare understories. Because these
are an exotic plant, maintenance of these flower
gardens has included additional fertilization and
installation of an irrigation system (
Figure 12).Andrews Park
• Andrews park has a natural creek running
through it (
Figure 13). The creek originatesoutside the town, and so the park provides a way
to connect several ecosystems as it meanders
through the park and town.
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 5
Figure 9.
A bird's-eye-view of another hardwood area inthe park shows very little remaining on the ground.
Figure 10.
All leaves have been removed and the resultingbare soil shows the exposed and unprotected roots of
shrubs and trees.
Figure 11.
This kind of management results in intensiveuse of people and energy resources.
Figure 12.
One of the park managers has plantedcamelias in one of the bare understories. Because these
are an exotic plant, maintenance of these flower gardens
has included additional fertilization and installation of an
irrigation system. Photo by Larry Korhnak
• Several ponds and other wetland areas support
habitat for wildlife in the park (
Figure 14).• A walkway across one of the wetland areas
offers entry and a look at this wetland ecosystem
(
Figure 15).• Fallen leaves and branches maintain a natural
mulch for the park (
Figure 16).• Playground areas are well-defined as are the
special areas where plant life is being restored
(
Figure 17)• Fallen logs are left lying next to hiking trails
and on the forest floor to enhance natural decay
and nutrient cycling (
Figure 18).• Signs are utilized to educate people about the
park's ecosystems (
Figure 19).Developing a Checklist
It's good to look thoughtfully and critically at
our parks, neighborhoods, waterways and other
urban forests to see how they contribute ecologically
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 6
Figure 13.
Andrews park has a natural creek runningthrough it. Photo by Larry Korhnak
Figure 14.
Several ponds and other wetland areassupport habitat for wildlife in the park. Photo by Larry
Korhnak
Figure 15.
A walkway across one of the wetland areasoffers entry and a look at this ecosystem. Photo by Larry
Korhnak
Figure 16.
Fallen leaves and branches maintain a naturalmulch for the park helping to sustain the nutrient cycle in
the ecosystem. Photo by Larry Korhnak
Figure 17.
Playground areas are well-defined as are thespecial areas where plant life is being restored.
to the community. These benefits can be utilized to
gain support for restoration projects. By using a
checklist we can estimate the benefits for any area
within the urban forest ecosystem.
A Checklist of Wilson and Andrews Parks
shows the contrasting ecological benefits of the two
parks (
Figure 20).Both parks contribute recreational benefits to
the community. The monoculture of loblolly pines
and the hardwood forests at Wilson Park provide
very little biodiversity compared to the natural
ecosystems with many structural layers and plants at
Andrews Park. Parking lots and forests with very
little understory vegetation and natural mulch result
in high levels of stormwater runoff at Wilson Park.
The creek and wetland areas along with the forest
floor with its high water infiltration rates offer
several ways to dispose of stormwater at Andrews
Park. Andrews is a low maintenance, low energy-use
park compared to the high energy levels to maintain
Wilson Park. The removal of all leaves, twigs, and
fallen logs at Wilson Park means that nutrients are
being removed from the site annually; this will
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 7
Figure 18.
Fallen logs are left lying next to hiking trails andon the forest floor to enhance natural decay and nutrient
cycling. Photo by Eliana Kampf Binelli
Figure 19.
Signs are utilized to educate people about thepark's ecosystems. Photo by Larry Korhnak
Figure 20.
By using a checklist we can estimate thebenefits for any area within the urban forest ecosystem.
This checklist compares the ecological benefits of Wilson
and Andrews parks.
contribute to impoverishment of the site over time.
In addition, organic matter will not be present in the
soil to aid in water and nutrient retention. This
interruption of the natural nutrient cycle can be
remedied easily by retaining fallen plant materials as
in Andrews Park.
And finally, the Socio-Economic category of
benefits. Parks, greenways and natural areas
contribute to the economic health of a community.
For example, before the construction of the Pinellas
Trail (greenway), the city of Dunedin, FL had a 50%
occupancy rate and now with the new greenway,
there are no vacancies (Department of
Environmental Protection 1996). People come or
stay to recreate in communities; wildlife watching
alone generates $18.1 billion in the nation (Caudill
1997). Real estate prices are enhanced with the
presence of natural areas, parks and trees. The
improved psychological well-being of the citizens in
a community or neighborhood with parks and trees
has also been documented (Schroeder and Lewis
1991). People viewing trees have slower heartbeats,
lower blood pressure, and more relaxed brain wave
patterns than people viewing urban areas without
vegetation (Ulrich 1981).
It can be very advantageous to quantify costs
and benefits for maintaining or restoring areas. In
addition to stormwater and energy conservation cost
reductions, other less tangible benefits such as health
and recreation can be demonstrated. Recreational
studies have shown that citizens often prefer
recreating in parks near their homes, emphasizing the
importance of community parks (Schroeder 1990).
In Chicago, 50% of all the people visiting forest
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 8
preserves traveled 10 minutes or less from their
homes (Young and Flowers 1982). In 1996, 2.7
million Floridians participated in wildlife
recreational activities within a mile of their homes
(Florida Game and Fresh Water Fish Commission
1998). It is very important for urban foresters to
demonstrate to their city councils and managing
agencies the importance of parks and trees as
infrastructure in their communities.
Where can We Restore?
The options for restoration sites and projects in
cities and communities are endless. Here are a few:
• Yards can be enhanced with native species or
even native ecosystems (
Figure 21).• Vacant lots, often ignored or treated poorly for
many years, are often candidates for restoration.
• The possibilities for better energy conservation
and stormwater management in shopping center
parking lots are great (
Figure 22).• Street trees, aging or lacking diversity, can be
restored.
• Schoolyards can become natural areas with
unlimited potential as educational areas.
• Industrials parks can be transformed.
• Waterways can be enhanced and connected to
support recreational and hydrological benefits
(
Figure 23).Figure 21.
Yards can be enhanced with native species oreven native ecosystems. Instead of a typical
mono-species hedge or a fence, this area between two
neighbors has been restored and planted with native
species.
Figure 22.
The possibilities for better energy conservationand stormwater management in shopping center parking
lots are great.
Figure 23.
Waterways such as this creek can beenhanced with native species and connected to support
recreational and hydrological benefits.
Examples of Sucessful Projects
One objective of this CD-ROM was to find and
showcase successful restoration projects in the U.S.
We have been overwhelmed with the variety and the
high quality of projects being implemented
throughout our cities and communities. There is a
tremendous amount of creativity, ingenuity, and hard
work going into these projects. The high quality and
success are due to the amount of effort by so many
talented people ranging from young children to
funding agency personnel to natural resource
managers and community development
professionals. Partnerships are a common ingredient
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 9
of these projects. As you can see the variety
illustrates the imagination involved and the potential
for even more new projects in other communities.
The Forest Park Ivy Removal Project in
Portland
Sandy Diedrich saw a problem in her
neighborhood park and decided to take the lead in
trying to remedy it. Forest Park, is a 5,000 acre urban
park in Portland, Oregon -- one of the largest urban
forested parks in the country. It has 70 miles of trails
and 30 miles of creeks and tributaries. But it also has
English ivy, a common landscaping plant, which has
invaded the park, covering the native understory
plants and trees, and reducing the biodiversity in the
forest. Controlling the ivy is a challenge - because it
is so mixed with the native plants, herbicides are not
feasible. Instead manual control is necessary (
Figure24
). In 1993, Sandy started a program withvolunteers, specifically with high school students
(
Figure 25). She developed workshops andworkdays when citizens would come to help. In
addition to eradicating the ivy in the park, the
workshops taught nearby residents methods for ivy
control in their yards - the source of the ivy in the
park (
Figure 26). Through their work with thisproject, the high school students learned about the
basic ecology of the park, working together as a
team, and the importance of environmental projects
in the community. Alex Johnson, a high school
student and crew leader, noted that, "It's a chance to
make a difference. I've never known about the forest
and here I've learned a lot about nature."
Figure 24.
Crew leaders demonstrate ivy removalmethods.
Figure 25.
Sandy Driedrich (center) with the crew leaders(Bruno Precciozzi, Kristin Harman, Alex Johnson, and
Heidi Dragoo) in the headquarters of the Forest Park Ivy
Removal Project.
Figure 26.
Standing in front of an area where ivy has beenremoved and the forest's natural biodiversity is returning.
Drew Gardens in New York
Ray Emanuel and several others in the Bronx,
New York identified a site in their community that
had potential to be restored. The site was a vacant lot
located next to a school; for years this lot was used
for dumping and even criminal activities. Their goal
was to transform the space into a park for the
community and the school children. This
community-driven initiative including corporations,
the Urban Resources Partnership, and the community
began with planning and clean-up of the site. Fall
clean-ups and spring festivals involve the community
and corporate volunteers. High school students work
at the gardens and this work program is part of a job
protocol educational program (
Figure 27). Severalhigh school classes utilize the gardens for their
instruction including art, language arts (especially
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 10
writing), and science classes. Ecology Days at the
gardens include stations where participants can learn
about subjects such as water testing of the Bronx
River, composting, small wildlife, and edible wild
plants (
Figure 28).Figure 27.
A vacant lot located next to a school in NewYork was transformed into a park for the community and
the school children.
Figure 28.
Included in this new park, named DrewGardens, are trails and a deck to view the Bronx River.
Apex Park in Tampa
Apex Park is on Davis Island, a small island in
Tampa. It is the first thing you see after you cross the
bridge to the island. And the residents wanted the
first impression to be the best. So they approached
Steve Graham, Tampa's urban forester for assistance
in restoring the site, a small piece of land about an
acre in size. After researching old photos and
documents and some remnant ecosystems in the area,
they arrived at a list of plants that would have made
up the ecosystem before development of the island
(
Figure 29). They were delighted to find one grass,twisted fiddle leaf, that was endangered and found
some specimens still remaining on the island (
Figure30
). They planted a small area with native tree andshrub species including twisted fiddleleaf. The other
small part of the park was landscaped with grass to
showcase and allow viewing of the native ecosystem
(
Figure 31). The park has kindled interest amongresidents in native species and several people have
landscaped their yards with many of these species.
Figure 29.
With the help of Steve Graham, Tampa's urbanforester, the community of Davis Island restored native
plants at Apex Park.
Figure 30.
One plant, twisted fiddleleaf, was endangeredso the community collected specimens and planted it at
the park.
Landscaping for Wildlife
An educational program developed by the
Florida Cooperative Extension Service has given
homeowners the knowledge and tools for
landscaping their backyards and small urban lots for
wildlife using ecological principles (
Figure 32).Workshops are aided by the inclusion of a
participant's guide, instructor's guide and videos
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 11
Figure 31.
The other part of the park was landscaped withgrass to showcase and allow viewing of the native
ecosystem.
developed by extension specialists. The first of three
modules entitled "Landscaping for Wildlife:
Providing Food in Your Yard" demonstrates how to
restore a remnant of native landscape, start a
bird-feeding program, control squirrels, plant a wild
bird food plot, and feed hummingbirds and
butterflies. The second module enables participants
to select plants to provide good wildlife cover
including bird and bat houses, burrows for toads and
other small mammals, treefrog houses, rock piles for
lizards and snakes and brush piles for birds and
rabbits
(Figure 33). The third module highlights theimportance of the third wildlife requirement - water.
Figure 32.
In the Landscaping for Wildlife program,homeowners learn how to enhance wildlife habitat in their
backyards. Photo by Joe Schaefer
Figure 33.
The second module enables participants toselect plants to provide good wildlife cover including bird
and bat houses, burrows for toads and other small
mammals, treefrog houses, rock piles for lizards and
snakes and brush piles for birds and rabbits. Photo by Joe
Schaefer
Naturescaping For Clean Rivers
Landscaping your backyard can have a positive
impact on the environment. That's the theme for
Portland's Naturescaping For Clean Rivers project
(
Figures 34 and 35). "Rainwater runoff, orstormwater, becomes a problem in urban areas
because of the thousands of acres of impervious
surface: roofs, roads, driveways, and parking lots,"
notes the project workbook. This runoff contains
contaminants such as oils, metals, and chemicals.
The goal of naturescaping is to improve the quality
and reduce the quantity of water reaching storm
drains. Workshops teach homeowners how to
landscape with native plants which require much less
water, fertilizers, mowing, and chemicals to maintain
(
Figures 36 and 37). Other classes includecomposting, attracting wildlife and reducing
pesticide use. Neighbors work together to host
workshops in their communities; all workshop
participants receive project workbooks which help
them develop an action plan for their yard.
Restoring Fire In Haile Plantation
A neighborhood in Gainesville, Florida wanted
to restore the native longleaf pine ecosystem as well
as reduce the fire hazard for their homes. In the past,
fire was a natural disturbance in Florida longleaf pine
ecosystems. Yet, development as well as new forest
practices have excluded fire from many of Florida's
ecosystems. The neighborhood decided to re-instate
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 12
Figure 34.
In the Naturescaping for Clean Rivers programhomeowners learn how to landscape with native plants
which require much less water, fertilizers, mowing, and
chemicals to maintain. Here a backyard is prepared for
planting. Photo by Linda Robinson
Figure 35.
The backyard is transformed into an energyand water efficient native landscape. Photo by Linda
Robinson
Figure 36.
Native wildflowers adorn a "naturescaped"backyard. Photo by Linda Robinson
Figure 37.
Butterfly gardens are a popular part of theNaturescaping program. Photo by Linda Robinson
this natural ecological process to the small patches of
forest in their community (
Figure 38). Fires reducethe competing hardwoods allowing longleaf pine to
regenerate and become reestablished in the
ecosystem (
Figure 39). Educational signs are a bigpart of the program.
Figure 38.
A neighborhood in Gainesville, Florida hasbrought fire in as a management tool to restore the native
longleaf pine ecosystem as well as reduce the fire hazard
for their homes. Photo by Eliana Kampf Binelli
Greening the Great River Park
The Mississippi River, as with most rivers in the
world, became a center of industry and shipping as
St. Paul, Minnesota became a prosperous city. But
often as with most industrial areas the native forests
along the river were destroyed and replaced with
industrial buildings, pavement, and warehouses. The
Greening the Great River Park Program, established
in 1995, seeks to restore many of these areas along
the River (
Figures 40 and 41). This public-privatepartnership includes The Saint Paul Foundation, City
of St. Paul and others including thousands of
volunteer and over 240 partner organizations. The
project involves the landscaping of over 100 private
industrial lands with the four native plant ecosystems
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 13
Figure 39.
Fires reduce the competing hardwoodsallowing longleaf pine to regenerate and become
reestablished in the ecosystem.
including 30,000 trees and shrubs that occupied the
area in the past. "Our goal is to have a 50% canopy
cover throughout the valley. In 20 to 25 years, as the
trees reach mature heights, we want the valley to
look as though the buildings were placed in a forest
rather than some trees were planted around
buildings."
Figure 40.
The Greening the Great River Park Program,established in 1995, seeks to restore many sites in
industrial areas along the River. This shows an industrial
site before restoration. Photo by Rob Buffler
Figure 41.
Over 100 private industrial lands have beenlandscaped and planted with four native plant
ecosystems. This shows the same site after restoration.
Photo by Rob Buffler
A Community Park in New York City
A one-acre lot used as a bus garage for many
years and next to three schools was the site for the
birth of a community park in New York City. The
planning began in 1990 with meetings involving the
whole community - city agencies, non-profit
organizations (headed by "Open Road"), students,
businesses, neighbors and more. The grass-roots
park design includes a greenhouse, basketball area,
nature pond with plantings, wildlife area, and
playground (
Figures 42). To restore this "brownfield" site the area needed to be lined with plastic and
new soil needed to be imported. However, the group
including professional engineers and school children,
decided to develop a composting system and produce
compost from nearby businesses to produce the
"soil." The newly invented composting system is
now sought by many other communities in New
York. School classes using the park range from
science and gardening to energy and physics to
poetry and art. A math class, for example, helped
design the greenhouse. Paula Hewitt, the project
creator and Open Road Director, emphasizes that
"the purpose of the park is to be educational, yet we
have a very relaxed, fun atmosphere" (
Figures 43and 44
). The park is open to the community everyday of the year.
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 14
Figure 42.
The planning for this community park in NewYork City began in 1990 with meetings involving the whole
community - city agencies, non-profit organizations
(headed by "Open Road"), students, businesses,
neighbors and more. The grass-roots park design
includes a greenhouse, basketball area, nature pond with
plantings, wildlife area, and playground.
Figure 43.
Paula Hewitt, the community organizer, looksfor turtles and fish in the park's pond with neighborhood
kids.
Figure 44.
Gerald Brinson, who started as a volunteer forthe park and is now part of the staff, describes the new
dock project with flowing water that he is constructing.
Bill Baggs Park
In 1991 Hurricane Andrew struck Miami and its
surrounding communities including Key Biscayne.
Bill Baggs Park which until that time was mostly
occupied with an invasive tree, Australian pine, was
completely destroyed (
Figure 45).Figure 45.
In 1991 when Hurricane Andrew struck southFlorida, the non-native Australian pine forest at Bill Baggs
Park on Key Biscayne was completely destroyed.
The nearly clean slate provided an opportunity
and several visionaries saw that it was a possible
chance to restore the park. With partnering between
federal, state, county, city and many non-profit
groups, a proposal and plan was developed to
re-create the park to the way it was 100 years ago.
They researched the five native ecosystems including
four wetland areas that had occupied the site
(
Figures 46 and 47).Historical and recreational amenities were also
considered - for example, without the shade of the
previous forest, nine picnic shelters needed to be
constructed (
Figure 48). Cultural history includingarchaeological findings were incorporated into the
plan (
Figure 49). The ecosystems were restored andfuture invasions of non-native plants were monitored
by volunteers. Educational displays were important
to inform the public about the process of restoration
as well as the diversity of the "new" ecosystems
(
Figures 50 and 51).Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 15
Figure 46.
With partnering between federal, state, county,city and many non-profit groups, a restoration proposal
and plan was developed to restore the park with the five
native ecosystems that it had 100 years ago. Old
documents were studied to carefully re-create and map
the ecosystems.
Figure 47.
The coastal strand ecosystem three years afterplanting shows the restoration success.
Figure 48.
The shade that had been removed with theAustralian pine tree canopy had to be replaced with
several picnic shelters.
Figure 49.
The historical, cultural, and archaelogicalsignificance of the site such as this 1825 lighthouse with
restored lighthouse-keeper's house was an important part
of the restoration plan.
Figure 50.
Involving the park's neighbors and thecommunity in all the stages was very important to the
restoration success. Nearby condominiums can be seen
from the restored south Florida slash pine ecosystem.
Streamside Restoration in Virginia
The Difficult Run Watershed in Virginia has
over one-half million acres of forests and urban
communities. Nonpoint source pollution is affecting
the water quality of the Difficult Run River and
downstream the Potomac River and Chesapeake
Bay. This restoration project is a partnership with
the Virginia Department of Forestry, Environmental
Protection Agency, Virginia Department of
Conservation and Recreation, Chesapeake Bay
Foundation and the USDA Forest Service. Together
they are striving to:
• Improve water quality by enhancing and
restoring streamside forests.
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 16
Figure 51.
Educational displays were important to informthe public about the process of restoration as well as the
diversity of the "new" ecosystems such as the mangroves
along the ocean and bay.
• Increase public awareness and education
regarding the value of riparian forests.
• Improve fish and wildlife habitat (
Figure 52).Over 8,000 trees have been planted to reestablish
riparian buffers or streamside forests to restore and
maintain this important watershed.
Figure 52.
The Difficult Run Watershed Project restoresstreamside forests which act as buffers to protect water
quality and fish and wildlife habitat in riparian ecosystems.
Photo by Judy Okay
The Two Key Ingredients
These projects have been very successful
because they all had two key ingredients. First, the
people. All projects became an essential part of the
community because they involved the people in the
community from the start and then in every step.
People included all stakeholders such as citizens (all
ages), businesses, non-profit groups, volunteers, and
government agencies. Collectively these people put
together the second key ingredient to success - a
plan. As you will see in Chapter 5, the successful
restoration plan contains a vision, goal, objectives,
action plans and evaluation tools. Well-developed
plans demonstrate the need for the project and are
used to seek public and financial support. These
plans are usually very effective at obtaining funding
and other in-kind support. Successful projects have
support of the people and a well laid-out plan (
Figure53
).Figure 53.
Successful restoration projects have two keyingredients - support of the people and a well laid-out plan.
Conclusions
There are many options for restoring ecological
benefits in your community. It is important to
consider the whole city or community as an
ecosystem and then to focus in on parcels or projects
that could benefit that ecosystem or landscape as a
whole. Restoration projects can be as small as
Chapter 1: Restoring the Urban Forest Ecosystem: An Introduction 17
backyards to parking lots, city streets, parks,
waterways and any place where there are or could be
trees. Most often it's important to start with a small
manageable project. The United States hosts an
abundance of successful and innovative urban forest
restoration projects. The Bronx's Drew Park brought
life back to a vacant lot next to a school. Portland's
Ivy Project removed invasive ivy at the 5,000 acre
Forest Park. Greening the Great Green River is
restoring industrial parks along the Mississippi
River. The possibilities for restoration projects are
unlimited and up to the imagination and energy of
people (
Figure 54). Planning and involving thecommunity - the stakeholders - are the two most
important ingredients for success.
Figure 54.
The possibilities for restoration projects areunlimited and up to the imagination and energy of people.
Literature Cited
Caudill, A. 1997. 1991 National impacts of non
consumptive wildlife related recreation. Div. of
Economics. US Fish and Wildlife Service.
Arlington. 8 p.
National Research Council. 1992. Restoration
of aquatic ecosystems: science, technology, and
public policy. Committee on Restoration of Aquatic
Ecosystems - Science, Technology and Public Policy,
Water Science and Technology Board, Commission
on Geosciences, Environment, and Resources.
National Academy Press. Washington, D.C. 552 p.
Florida Department of Environmental
Protection. 1996. Environmental Benefits of
Greenways Summary Sheet. 2 p.
Schroeder, H. 1990. Perceptions and
preferences of urban forest users. Journal of
Arboriculture 16(3):58-61.
Schroeder, H. and C. Lewis. 1991.
Psychological benefits and costs of urban forests.
Pages 66-68 In: Proceedings of the Fifth National
Urban Forest Conference. Los Angeles, CA.
Ulrich, R.S. 1981. Natural versus urban scenes:
Some psychophysiological effects. Environment and
Behavior. 13:523-556.
Young, R.A. and M.L. Flowers. 1982. Users of
an urban natural area: their characteristics, use
patterns, satisfactions, and recommendations.
University of Illinois, Department of Forestry,
Forestry Research Report 82-4.
Chapter 2: Basic Ecological Principles for Restoration1
Mary L. Duryea, Eliana Kämpf Binelli, and Henry L. Gholz
21. This is Chapter 2 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Mary L. Duryea, Professor and Extension Forester, Eliana Kämpf Binelli, Extension Forester, and Henry L. Gholz, Professor, School of Forest Resources
and Conservation, Institute of Food and Agricultural Sciences, University of Florida, PO Box 110410, Gainesville, FL 32611
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Traditionally the urban forest has been viewed
as trees in the city - often along streets and in small
groups in other public places such as parks.
However, another way to look at the urban forest is
as an ecosystem, including many more living
components than trees (people, shrubs, herbs,
animals, microorganisms), a physical environment
(light, moisture, soil, rocks), energy flow from the
sun and water and nutrient cycles. A first step in
reorienting our view of urban forests and their
management is to review some important ecological
principles and to see how they apply to restoration
and management. The goal of this chapter is to
examine urban forests as ecosystems and to discuss
some of the opportunities for managing urban forest
ecosystems to provide more natural benefits to
communities and cities. By comparing the present
state of the urban forest ecosystem (UFE) to natural
ecosystems, we can learn how to manage the UFE for
some of the natural benefits it can provide. These
include energy conservation, stormwater
management, wildlife conservation, and recycling or
solid waste management. The urban forest
ecosystem is an open system with energy and
materials constantly entering and leaving the system.
Producers (mainly green plants) and consumers
(organisms dependent on living and dead plant and
animal matter) make up the living portion of all
ecosystems which are linked together in complex
networks called food webs. Cities are largely
consumers relying on production of food, energy and
natural resource from outer agricultural, forested and
other natural areas. The urban forest ecosystem can
provide many opportunities for ameliorating the
drain and stress on our natural resources. For
example, by cooling the city with a forest canopy, we
are less dependent on outside natural resources for
air conditioning. By providing natural areas for
water infiltration, storage and evaporation of
rainwater, the waste water from our streets and other
impervious surfaces is reduced. When leaves,
branches, and grass-clippings are left on-site instead
of being removed, these natural materials sustain the
natural nutrient cycle and provide the same benefits
that we ascribe to mulches in gardens and landscapes.
Urban forests can also help reduce atmospheric CO
2build-up in two ways by reducing fossil fuel (energy)
use and by increasing carbon storage. Finally, the
UFE can provide wildlife habitat and help with the
movement and conservation of some organisms
through connectivity. Seven guidelines to restore and
manage the urban forest ecosystem are: (1) Restore
and manage the UFE to decrease consumption and
contribute to conservation; (2) Restore and manage
Chapter 2: Basic Ecological Principles for Restoration 2
the UFE for its water cycling benefits; (3) Restore
and manage the nutrient cycle within the UFE:; (4)
Restore and manage the UFE to support greater
biodiversity; (5) Restore natural forest ecosystems in
the city; (6) Educate policy makers, city managers
and the public about the benefits of a healthy UFE;
and (7) Incorporate UFE management and
restoration into urban and regional planning.
Introduction
Traditionally the urban forest has been viewed
as trees in the city - often along streets and in small
groups in other public places such as parks
(Figure1)
. Managing these trees has included inventoryingthe tree population and assessing their health. We
have cultured and managed them mostly as
individuals, and this is called arboriculture.
However, another way to look at urban forests is as
ecosystems, with many more components (people,
animals, microorganisms), a physical environment
(sidewalks, soil, rocks), energy flow (sun) and
processes (water, nutrient cycles)
(Figure 2). Thisecological perspective is more comprehensive,
incorporating biological, physical, chemical and
social components. This approach offers a great
opportunity to enhance the environmental benefits of
forests in urban areas. The environmental benefits
gained from a healthy urban forest ecosystem (UFE)
include energy savings, reduction of waste and
stormwater costs, water quality improvement,
increased recreational opportunities and enhanced
wildlife and biodiversity conservation. With this
outlook we also have the additional opportunity to
think in the long-term and to consider the urban
forest as part of the larger landscape.
Figure 1.
Traditionally the urban forest has been viewedas trees in the city - often along streets and in small groups
in other public places such as parks.
A first step in reorienting our view of urban
forests and their management is to review some
important ecological principles and to see how they
apply to restoration and management. The goal of
this chapter is to examine urban forests as ecosystems
and to discuss some of the opportunities for
managing urban forest ecosystems to provide more
natural benefits to communities and cities.
Figure 2.
Another way to look at the urban forest is as anecosystem with many more components (people, animals,
microorganisms), a physical environment (sidewalks, soil,
rocks), energy flow (sun) and processes (water, nutrient
cycles).
The Urban Forest As An Ecosystem
An urban forest ecosystem (UFE) is a collection
of living matter (plants, animals, people, insects,
microbes) and nonliving matter (soil, rocks and dead
organic matter) through which there is a cycling of
nutrients and water and a flow of energy from the
sun. Based on this definition the UFE represents not
only the trees but also the other components
(including humans, microbes, wildlife and the
physical environment) and the interaction of these
components.
What are the boundaries of a UFE? We can
consider UFEs to be the whole city or smaller parcels
within the city. The boundaries of the UFE depend
Chapter 2: Basic Ecological Principles for Restoration 3
on the nature and scope of our management goals.
No matter what the boundaries of the ecosystem are,
each ecosystem is linked to other surrounding
ecosystems
(Figure 3). As we noted above, urbanand rural ecosystems also overlap and interact to
form landscapes. All the ecosystems on earth
together form the biosphere, which contains all of the
life on earth.
Figure 3.
We can consider the UFE to be the whole city orsmaller parcels within the city depending on our
management goals. The UFE is linked to other
surrounding ecosystems which together form the
landscape.
Why View the Urban Forest
Ecosystem as an Ecosystem?
Cities are part of what used to be rural
landscapes, most of them originally forested
(Figure4)
.Figure 4.
Cities are part of what used to be rurallandscapes. Here you can see the natural forest edges of
this small city. Photo by Hans Riekerk
By comparing the present state of the urban
ecosystem to natural ecosystems, we can learn how
to manage the UFE for some of the natural benefits it
can provide
(Figure 5). These include energyconservation, stormwater management, wildlife
conservation, and recycling or solid waste
management. Also, by taking an ecosystem view, we
can better understand the importance of the structure
and function of UFEs which may help solve local
problems such as flooding, and air and water
pollution. By focusing on urban ecosystem
management we can also contribute to solving larger
scale problems such as biodiversity conservation and
reduction of atmospheric CO
2 concentrations.Figure 5.
By comparing the present state of the urbanecosystem to natural ecosystems, we can learn how to
manage the UFE for some of the natural benefits it can
provide. Photo by Larry Korhnak
The Structure and Function of the
UFE
The UFE is an open system (in thermodynamic
terms) with materials and energy constantly entering
and leaving
(Figure 6).Energy from the sun is fixed by plant leaves in
the UFE. Some of the absorbed energy then flows
out of the ecosystem as heat, which warms the air
(Figure 7)
.The rest of the absorbed solar energy is used to
evaporate or transpire water. Materials entering the
UFE may be in the form of nutrients (fertilizers),
water (in rainfall or irrigation), plants (new plantings
or seeds from invasive plants) or other forms of
non-solar energy, such as fossil fuels
(Figure 8).Chapter 2: Basic Ecological Principles for Restoration 4
Figure 6.
The urban forest ecosystem is an open systemwith energy and materials constantly entering and leaving
the system.
Figure 7.
Energy from the sun is fixed by plant leaves inthe UFE.
Figure 8.
Fossil fuels are one of the materials entering theUFE for management.
Forms of these same materials may leave the
UFE in runoff (storm water), with the wind (seeds)
or in trucks going to landfills (yard and solid waste)
with much converted to CO
2 and heat (Figure 9).Figure 9.
Pruned branches and leaves are materials oftenleaving the UFE to end up in landfills.
The UFE may have a very complex structure
with a variety of layers including a tree canopy, a
shrub understory, an herb layer and a litter layer. The
UFE is made up of living things, called biotic
components (living plants and animals) and
nonliving things, called abiotic components (soil, air,
nutrients, water, dead organic matter). Nutrients
(such as nitrogen, phosphorus and calcium) and
water cycle from the abiotic parts of the ecosystem
to the biotic parts and back again. These are called
nutrient and water cycling, respectively.
There are two major groups of the living things
in the UFE: (1) producers (also called autotrophs)
and (2) consumers (also called heterotrophs)
(Figures 10
and 11).Producers, which are mainly green plants, take
light energy and store it through the process of
photosynthesis. Consumers cannot photosynthesize
but instead feed directly on the producers (i.e.,
herbivores) and other consumers (i.e., carnivores or
detritivores or decomposers). Consumers include
non-photosynthetic bacteria, fungi, and animals,
Chapter 2: Basic Ecological Principles for Restoration 5
Figure 10.
One of the two major groups of living things inthe UFE is producers (also called autotrophs).
Figure 11.
The other major group of living things in theUFE is consumers (also called heterotrophs) which cannot
photosynthesize but instead feed directly on the producers
(i.e., herbivores) and other consumers (i.e., carnivores and
decomposers).
including humans. Producers and consumers are
linked together in complex networks called food
webs
(Figure 12). Food webs are important torecognize in UFE management, because the
disruption or elimination of one part of the web may
impact other organisms and ecosystem functioning in
unexpected ways.
Figure 12.
Producers (mainly green plants) andconsumers (organisms dependent on living and dead plant
and animal matter) are linked together in complex
networks called food webs.
Comparing Natural and Urban Ecosystems
Natural ecosystems have a balance of
production and consumption constantly operating. If
by chance the ecosystem produces more than it
consumes, the excess energy is stored as carbon (in
the wood of tree stems, peat in bogs, etc.). If a fire
or another disturbance lowers plant production, the
consumer populations will adapt accordingly. Cities,
on the other hand, are largely consumers relying on
production of food, energy and natural resources in
outer agricultural, forested and other natural areas
(Odum 1983)
(Figure 13). Seldom do cities producethese necessities within their perimeter in quantities
sufficient to support large numbers of people. At the
same time, cities must contend with the wastes that
are produced, often sending solid wastes and waste
water out of the city.
Figure 13.
Cities rely on natural and domesticatedenvironments for resources. At the same time these cities
must contend with the wastes that are produced, often
sending solid wastes and waste water out of the city
(adapted from Odum 1983).
Chapter 2: Basic Ecological Principles for Restoration 6
How Can the UFE Help?
The urban forest ecosystem can provide many
opportunities for ameliorating the drain and stress on
our natural resources. For example, by cooling the
city with a forest canopy, we are less dependent on
outside natural resources for air conditioning
(Figure14)
.Figure 14.
By cooling the city with a forest canopy, we areless dependent on outside natural resources for air
conditioning. Photo by Hans Riekerk
By providing natural areas for water infiltration,
storage and evaporation of rainwater, the waste water
from our streets and other impervious surfaces is
reduced
(Figure 15).Figure 15.
By providing natural areas for water infiltration,storage and evaporation of rainwater, the waste water
from our streets and other impervious surfaces is reduced.
Photo by Larry Korhnak
By providing places for recreation, fewer people
will need to use fossil fuels to leave the city for their
nature experiences
(Figure 16).Figure 16.
By providing places for recreation, fewerpeople will need to use fossil fuels to leave the city for
their nature experiences. Photo by Larry Korhnak
By supporting, for example, water quality,
forest management, and growth management policies
for lands outside our cities, we will sustain our
natural and domesticated ecosystems. Infusing our
cities and communities with more urban forest
ecosystems will restore natural structure and
processes to our urban forests making us less
dependent on our limited natural resources outside
the city.
Characteristics of the UFE
The Urban Heat Island
Cities can reach temperatures 7
o to 15o F higherthan in the surrounding rural ecosystems. This is
called the urban heat island effect
(Figure 17).Figure 17.
A city is 7o to 15o F warmer than thesurrounding countryside. Adapted from Oke 1982.
Chapter 2: Basic Ecological Principles for Restoration 7
Some of the reasons for this heat buildup are:
(1) cities generate heat from burning fossil fuels
(factories, cars, heating and air conditioning),
(2) city structures absorb and store solar heat
(especially dark surfaces such as asphalt roads and
dark roofs),
(3) through decreased vegetation and rapid
routing of rainwater to storm sewers, cities have
much less natural cooling due to the evaporation and
transpiration of water,
(4) air pollutants may slow the outflow of heat
away from urban surfaces, and
(5) cities usually have less air movement to take
heat out of the city (Lowry 1967; Oke 1982).
Large numbers of trees can reduce local air
temperatures by 1
o to 9o F (McPherson 1994).Evapotranspiration by trees lowers air temperatures
in two ways. First, when precipitation is intercepted
by trees and other plants, the evaporation of this
water cools the air. Secondly, trees constantly take
up water from the soil and lose water to the air. This
process, called transpiration, also lowers air
temperature. Therefore, the UFE can reduce heat
buildup in the city by storing less heat, using more of
the sun's energy for evaporative cooling, and shading
buildings and other surfaces so that they require less
fossil fuel energy for cooling
(Figures 18 and 19).Figure 18.
The urban forest ecosystem throughevaporative cooling and shade can contribute to reducing
the temperatures in the urban heat island. This parking lot
is a contributor to high temperatures in the urban heat
island.
Figure 19.
The urban forest ecosystem throughevaporative cooling and shade can contribute to reducing
the temperatures in the urban heat island. This parking lot
demonstrates trees properly placed to reduce temperature.
Nutrient Cycling in the UFE
Chemicals circulate from the plants and animals
to the soil and back again, as part of the nutrient
cycle
(Figure 20). The health of plants in theecosystem is mainly dependent on the soil for its
source of nutrients. Dead organic matter in the soil,
also called detritus, is the long-term storage site for
essential nutrients. Decomposers (primarily
microrganisms) break down the detritus and release
the nutrients held in the organic matter into organic
forms that can be reused by plants, thus completing
the nutrient cycle. In the UFE, this cycle is often
disrupted or arrested because most of the dead
organic material such as lawn clippings, leaves,
branches, and logs are removed and hauled to landfill
sites or chipped for application to other sites. By
doing so, we are denying the UFE of a readily
recyclable source of fertilizers, which then must be
imported in the form of man-made fertilizers.
What happens when we remove these natural
materials from a backyard, a park, or a schoolyard in
the UFE?
• the soil may be exposed, resulting in erosion,
• plant roots may be exposed and desiccated or
damaged
(Figure 21),• fossil fuels are used to blow leaves, clean the
site and transport the yard waste to landfills or
compost piles
(Figure 22),Chapter 2: Basic Ecological Principles for Restoration 8
Figure 20.
Chemical elements in ecosystems circulatefrom the plants and animals to the soil and back again, as
part of the nutrient cycle.
• the organic matter removed no longer helps the
moisture and nutrient holding capacity of the
soil,
• wildlife and other organisms that depend on
decaying wood or litter for habitat and/or food
cannot live in this neatly maintained
environment,
• precious plant nutrients are removed often
requiring fertilizer applications for replacement
(Figure 23)
,• fertilizers, water, mulches, and pesticides
brought in to support and maintain this altered
system are manufactured at a great fossil fuel
cost.
Figure 21.
When natural plant materials are removed froma landscape, many plant roots may be exposed and
desiccated or damaged.
Figure 22.
Many leaves and branches that could be piledor spread (recycled) in a homeowner's landscape are
instead transported to landfills or urban compost piles.
Figure 23.
Precious plant nutrients are removed from thelandscape either resulting in plant deficiencies or requiring
fertilizer applications.
Instead of using tremendous amounts of energy
to remove branches, leaves, and snags, we can utilize
these materials to sustain the health of the UFE.
These natural mulches can be recycled on-site for
free where they will serve as natural fertilizers.
When they remain on-site, these natural materials
provide all the benefits that we ascribe to mulches in
gardens and landscapes
(Figure 24).It is quite feasible to take advantage of natural
nutrient cycling processes in UFE, contributing in the
process to conservation (water, energy, and soil) and
improving the environment both locally and globally.
Landscapers need to change many ingrained
practices, such as leaving more dead plant materials
on the ground. Creating "natural" or "semi-natural"
Chapter 2: Basic Ecological Principles for Restoration 9
Figure 24.
When leaves, branches, and grass-clippingsare left on-site, these natural materials provide all the
benefits that we ascribe to mulches in gardens and
landscapes.
areas in parks, backyards and other appropriate sites
will have favorable results for nutrient cycling and
other UFE processes such as cycling.
Water Cycling in the Urban Forest
Water forms a critical link between the earth's
surface and the atmosphere. After water falls to earth
as rain (and in other forms), it flows downhill into
creeks or soaks into ground, entering the ground
water (
Figure 25).Figure 25.
In the water cycle, water falls to the earth asprecipitation, enters the ground or flows as runoff to rivers,
lakes and the ocean, and is taken up (used) by plants and
other organisms. By evaporation from vegetation, land
and bodies of water, water re-enters the atmosphere to
begin the cycle once again.
Water in creeks flows into rivers, lakes and
finally the ocean. Water reenters the atmosphere by
evaporation from the land and sea and and by
evaporation and transpiration from vegetation (see
Chapter 6 - The Hydrological Cycle
). In the UFE,impervious surfaces such as buildings, paved streets
and parking lots interrupt this water cycle by
collecting the water and channeling it into sewers,
canals and other structures.
The consequences of interrupting the natural
water cycle include:
1. decreased infiltration of water into soil,
2. more runoff, which must then be managed and
accomodated,
3. decreased water quality as pesticides, fertilizers
and other polluants are concentrated in the
collected runoff,
4. erosion of unprotected soils and
5. less evaporation of water with its associated
cooling effect.
How does the UFE help restore the water cycle?
First, vegetation in the UFE intercepts rainfall and
evaporation of this water helps cool the city. Second,
soils absorb water; then it is either taken up by plants
or percolates to the water table or creeks instead of
running into storm sewers. The result is lower
stormwater treatment costs and less flooding
potential in the city (
Figures 26 and 27).Figure 26.
In the city, impervious surfaces such asbuildings, paved streets and parking lots interrupt the
water cycle by collecting the water and channeling it into
sewers, canals and other structures. Photo by Larry
Korhnak
Chapter 2: Basic Ecological Principles for Restoration 10
Also, if soils are protected with mulches and
plants, less erosion will result in less sediment
entering the water. Wetlands also serve as storage
areas for water. Restoring and managing wetlands in
cities will lower the rate and volume of stormwater
runoff, control floods and erosion and help purify
water that will reach the water table. For example,
after storm in Dayton, Ohio the existing urban forest
reduced runoff by 7%. A slight increase in the urban
forest canopy could reduce runoff by 12% (Sanders
1984).
Figure 27.
Soils in the UFE absorb water; then it is eithertaken up by plants or percolates to the water table or
creeks instead of running into storm sewers. Photo by
Larry Korhnak
Educating policy makers, city managers and the
public about the benefits of vegetation in the UFE
and cost-saving potential is essential to more efective
management of the water cycle. For further
discussion on the water cycle, see
Chapter 6- TheHydrological Cycle
.Carbon Storage and Sequestering by UFEs
Carbon dioxide (CO
2) in the atmosphere isincreasing globally and is the principal contributor to
the expected increase in the greenhouse effect
(global warming). The two main sources of CO
2 arethe burning of fossil fuels and deforestation
(Houghton et al. 1996). Trees, litter, soil and organic
matter all store carbon (C). Since organic matter
contains 50% C, the more biomass (plant and animal
matter) on the earth, the less CO
2 in the atmosphere.In an ecosystem, carbon is taken in as CO
2 inthe process of photosynthesis
(Figure 28). Carbon iseither stored as living or dead plant material or
consumed by other organisms in the food web. CO
2is also given off during respiration. Forests can store
much greater amounts of C in the vegetation and
soils than any other type of ecosystem on earth due
mainly to the relatively massive storage in tree stems.
Figure 28.
In an ecosystem carbon is taken in as CO2
in
the process of photosynthesis. Carbon is either stored as
living or dead plant material or consumed by other
organisms in the food web. CO
2
is also given off during
respiration.
Can the UFE help to store more carbon? Forests
store carbon in their plants, roots, forest litter and
animals. One urban study estimated that the 69
million acres of urban forest in the U.S., with an
average of 28% canopy cover, store annually a net
6.5 million tons of C (Rowntree and Nowak 1991).
However, the whole world puts out 5.4 billion tons C
per year (deforestation alone accounts for 1.6 billion
tons) (Sundquist 1993). Urban forests in the USA
therefore currently only remove 0.1% of the output.
Even though urban forests are not likely to be better
managed just for C sequestration, it is important to
recognize that C sequestration by the UFE is an
additional benefit, albeit small.
To summarize, the UFE can contribute to reduce
atmospheric CO
2 in two ways: First, by reducingfossil fuel (energy) use in the cities
(Figure 29);Second, by increasing C storage from planting and
managing trees especially in cities where tree cover
is currently low.
Chapter 2: Basic Ecological Principles for Restoration 11
Figure 29.
The UFE can contribute to reduce atmosphericCO
2
by reducing fossil fuel (energy) use in the cities.
Wildlife in the UFE
Urbanization and urban sprawl have resulted in
habitat loss, highly fragmented forests, drained
wetlands and disrupted migration routes for wildlife.
Also, in many situations wildlife is dependent upon
two or more ecosystems, and these may not be
available. A forest fragment is a small parcel
separated from the larger forest (see also
Chapter 3- Biodiversity
). In the UFE, forest fragments oftenbecome small parks or undeveloped and often
degraded land. These fragments may be too small or
too distant to support many wildlife species
characteristic of natural areas. However, by
connecting some smaller fragments, larger
ecosystems can be simulated and some migration
routes and habitats restored
(Figures 30 and 31). Forfurther discussion on wildlife, see
Chapter 8 -Wildlife
.Figure 30.
This creek outside of a small city is connectedto a wetland inside the city allowing migration of some
wildlife species. Photo by Hans Riekerk
Figure 31.
By connecting some smaller fragments, largerecosystems can be simulated and some migration routes
and habitats for wildlife may be restored. Photo by Larry
Korhnak
Biodiversity
Until recently, efforts in biological conservation
have largely focused on preservation and protection
of individual species, subspecies and populations,
through the implementation of the Endangered
Species Act. However, scientists and practitioners
are realizing today that this has not always been
successful or even possible, and that many other
species have been ignored as a result. More recently
there is a greater focus on ecosystem management
with the idea that by managing and restoring whole
ecosystems, biodiversity and whole food webs, as
well as individual species, may be better protected.
Urban forests, which range from highly degraded
woodlots to monocultures of exotic trees to
semi-natural ecosystems, may play an important role
in managing for biodiversity. Although urban forests
cannot be expected to support all species groups (for
example large mammals or other wide-ranging
animals), if effectively managed, they can provide
habitat at a smaller scale, increase the effectiveness
of larger nearby reserves, and help with the
movement and conservation of some organisms
through enhanced connectivity
(Figure 32).Thus urban forests can be "stepping stones
between ecosystems" (Franklin 1993)
(Figure 33).At a smaller scale, biodiversity can also be restored
by enhancing the ecosystem's natural structure,
creating multi-age ecosystems in several stages of
succession, controlling invasive plant and animal
species, leaving stumps, leaves, snags and logs to
Chapter 2: Basic Ecological Principles for Restoration 12
Figure 32.
Although urban forests cannot be expected tosupport all species groups (for example large mammals or
other wide-ranging animals), if effectively managed, they
can provide habitat at a smaller scale, increase the
effectiveness of larger nearby reserves, and help with the
movement and conservation of some organisms through
enhanced connectivity. A corridor of forest provides this
connectivity. Photo by Henry Gholz.
improve nutrient cycling and for wildlife and by
planting native species that mimic composition of
nearby ecosystems. (For further discussion, see
Chapters 3 - Biodiversity
, 4 - Plant Succession andDisturbances
, and 9 - Invasive Plants.)Figure 33.
Urban forests can be "stepping stonesbetween ecosystems" (Franklin 1993).
Opportunities for Restoring and
Managing the UFE More
Ecologically
How can we restore and manage the urban forest
ecosystem? We propose the following seven
guidelines:
Restore and manage the UFE to decrease
consumption and contribute to conservation:
• Take advantage of natural nutrient cycling
by leaving grass clippings, leaves, branches
and logs on the ground and thereby reduce
the tremendous amount of energy expended
to remove plant materials from the
landscape.
• Plant and maintain trees around buildings
to reduce energy consumption for cooling
and heating.
• Save energy used for stormwater
management by increasing areas within the
UFE for water infiltration and evaporation.
• Manage the UFE to encourage recreation
in the city, thereby decreasing energy
consumption for travel to distant recreation
sites.
• Plant tree species that are adapted to local
conditions and require only natural rainfall
(after establishment) to save water and
energy costs from irrigation.
Restore and manage the UFE for its water
cycling benefits:
• Decrease storm water runoff and flooding
by increasing pervious surfaces (soils) in
the city to absorb water.
• Encourage increased canopy and
vegetation for increased evaporation and
transpiration of water to decrease
stormwater runoff and treatment costs.
Chapter 2: Basic Ecological Principles for Restoration 13
• Increase the retention of water in the UFE
for evaporative cooling to lower urban heat
island temperatures.
• Increase soil water infiltration in UFE soils
along with the retention of sediments and
pollutants to improve water quality.
• Restore and manage wetlands in cities to
lower the rate and volume of stormwater
runoff, control floods and erosion and help
purify water that will reach the water table.
Restore and manage the nutrient cycle within
the UFE:
• Leave grass clippings, leaves, branches
and logs on the ground to decompose and
provide nutrients.
• Use less fertilizers by taking advantage of
nutrients that naturally exist and cycle
through the system.
• Rake and distribute on-site mulch in the
UFE to protect the soil, retain moisture and
increase the nutrient holding capacity of the
soil.
• Plant less nutrient-demanding species.
Restore and manage the UFE to support
greater biodiversity:
• Include many different species and life
forms (herbs, shrubs, trees) in the UFE to
provide wildlife habitat and resist
disturbances.
• Restore small ecosystems (with their
structure and function) as important
connections in the landscape.
• Restore and manage waterways to connect
with other ecosystems.
Restore forest ecosystems in the city:
• Take a role in restoring natural ecosystems
by establishing one on a vacant lot, in a
schoolyard, at a park or another potential
site.
• Restore smaller model ecosystems to serve
as demonstration sites for restoration and
ecology education.
• Educate people about the UFE by restoring
or improving the health of degraded
ecosystems.
• Reduce deforestation by encouraging
developers to retain more green space or
larger forest areas in their developments.
Educate policy makers, city managers and the
public about the benefits of a healthy UFE:
• Cost-savings benefits,
• Recreation opportunities,
• Tourism benefits of healthy UFE's,
• Energy-saving,
• Wildlife conservation,
• Benefits to natural cycles and recycling,
• Water quality improvement,
• Stormwater management, and
• Carbon sequestration.
Incorporate UFE management into urban
and regional planning:
• Demonstrate how the UFE will benefit
regional environmental, economic and
social health.
• Be involved in the planning process to
incorporate UFE management into plans.
• Educate people to think about the UFE
when developing new areas and in
downtown redevelopment projects.
• Consider and educate people about the
ecological, economic and social benefits of
the UFE at the local to global scale.
Chapter 2: Basic Ecological Principles for Restoration 14
Additional Readings
Chameides, W.L., R.W. Lindsay, J. Richardson,
and C.S. Kiang. 1988. The role of biogenic
hydrocarbons in urban photochemical smog: Atlanta
as a case study. Science 241:1473-1476.
Gilbert, O.L. 1989. The ecology of urban
habitats. Chapman and Hall, NY.
Gill, D. and P. Bonnett. 1973. Nature in the
urban landscape: A study of city ecosystems.
Baltimore: York Press.
Goldman, M.B., P.M. Groffman, R.V. Pouyat,
M.J. McDonnell, and S.R.A. Pickett. 1995. CH4
uptake and N availability in forest soils along an
urban to rural gradient. Soil Biological Biochemistry
27(3):281-286.
Lyons, T.J., J.R. Kenworthy, and P.W.G.
Newman. 1990. Urban structure and air pollution.
Atmospheric Environment 24B:43-48.
Naiman, R.J., Décamps, H. and M. Pollock.
1993. The role of riparian corridors in maintaining
regional biodiversity. Ecological Applications
3(2):209-212.
Vitousek, P.M., P. Ehrlich, A. Ehrlich, and P.M.
Matson. 1986. Human appropriation of the products
of photosynthesis. Bioscience 36:368-373.
White, C.S. and M.J. McDonnell. 1988.
Nitrogen cycling processes and soil characteristics in
an urban versus rural forest. Biogeochemistry
5:243-262.
Cited Literature
Akbari, H., S. Davis, S. Dorsano, J. Huang, and
S. Winnett. 1992. Cooling our communities: A
guidebook on tree planting and light colored
surfacing. US Environmental Protection Agency and
Lawrence Berdeley Laboratory Report LBL-31587.
Franklin, J.F. 1993. Preserving biodiversity:
Species, ecosystems, or landscapes? Ecological
Applications 3:202:205.
Houghton, J.T., L.G. Meira Filho, N. Callander,
N. Harris, A. Kattenberg, and K Maskell. (eds.)
1996. Climate change 1995, the science of climate
change. Working Group 1, Intergovernmental Panel
on Climate Change, Cambridge University Press.
Lowery, W.P. 1967. The climate of cities.
Scientific American 217:15-23.
McPherson, E.G. 1994. Energy-saving potential
of trees in Chicago. In Chicago's urban forest
ecosystem: Results of the Chicago Urban Forest
Climate Project, edited by E.G. McPherson, D.J.
Nowak, and R.A. Rowntree. Gen. Tech. Rep.
NE-186. Radnor, PA: USDA Forest Service,
Northeast Forest Experiment Station.
Odum, E.P. 1983. Basic ecology. Fort Worth,
TX: Saunders College Publishing.
Odum, E.P. 1993. Ecology and our endangered
life support systems. Sunderland, Massachusetts:
Sinauer Associates, Inc.
Oke, T.R. 1982. The energetic basis of the urban
heat island. Quarterly Jounal of the Royal
Meteorological Society 108:1-24.
Rowntree, R.A. and D.J. Nowak. 1991.
Quantifying the role of urban forests in removing
atmospheric carbon dioxide. Journal of
Arboriculture 17:269-275.
Sanders, R.A. 1984. Urban vegetation impacts
on the urban hydrology of Dayton Ohio. Urban
Ecology 9:361-376.
Sundquist, E.T. 1993. The global carbon
dioxide budget. Science 259:934-941.
Chapter 3: Biodiversity and the Restoration of the Urban
Forest Ecosystem1
Eliana Kämpf Binelli
21. This is Chapter 3 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Eliana Kämpf Binelli, Extension Forester, School of Forest Resources and Conservation, Cooperative Extension Service, Institute of Agricultural
Sciences, University of Florida, PO Box 110410, Gainesville, FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Biodiversity is the variety of life and all the
processes that keep life functioning. Global
biodiversity provides many ecosystem services, such
as protection of water resources, nutrient storage and
cycling, and pollution mitigation. These ecosystem
services have recently been estimated to provide $33
trillion per year. Biodiversity occurs at many levels
from genetic diversity to species diversity to
ecosystem diversity. Biodiversity has been reduced
in urban areas through ecosystem destruction,
degradation and fragmentation of remaining
ecosystems. Biodiversity can be increased in urban
areas by managing the landscape as a whole and
improving connectivity between ecosystem
fragments. Biodiversity can also be restored by (i)
leaving stumps, leaves, snags and logs to improve
nutrient cycling and for wildlife, (ii) planting native
species that mimic composition of nearby
ecosystems, (iii) controlling invasive plants and
animals, (iv) enhancing the ecosystem's natural
structure, and (v) creating multi-age ecosystems in
several stages of succession. Ecological processes to
restore include natural disturbances (e.g., fire),
ecological succession, nutrient cycling and
hydrological cycling.
Introduction
While watching TV, reading newspapers,
listening to the radio or even talking to friends, we all
have heard something about biodiversity. Issues
such as old-growth forests and the spotted owl,
tropical deforestation, hunting of whales and many
other topics related to biodiversity have made the
news.
Biodiversity has emerged as one of the key
environmental concerns in the debate over the
worldwide depletion of natural resources.
Biodiversity is now a matter not only of scientific
interest but also public concern throughout the
world.
But, what exactly is biodiversity? Why is it
important? Are urban forests important to the
conservation and maintenance of biodiversity? Why
should urban foresters, citizens, policy makers and
professionals be concerned about biodiversity in
urban areas? Can we restore biodiversity in our
cities? How? This publication will discuss these
questions and how managers can incorporate
biodiversity into urban forest restoration projects.
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 2
What Is Biodiversity?
Biodiversity, the short term used for biological
diversity, is "the variety of life and all the processes
that keep life functioning" (Keystone Center 1991).
Biodiversity includes 1) the variety of different
species (plants, animals - including humans,
microbes and other organisms), 2) the genes they
contain, and 3) the structural diversity in
ecosystems.
The wealth of biodiversity supports ecological
processes which are essential to maintain ecosystems
on earth
(Figure 1). Examples of such ecologicalprocesses are the nutrient cycle, the hydrological
cycle, and natural succession.
Figure 1.
The exact number of existing species in theworld is unknown, with estimates varying from as low as 5
million to as high as 100 million species. Most are insects
that play critical roles in ecosystems such as
decomposition and nutrient cycling.
One of the most fundamental attributes of
biological diversity is that it is always changing. The
wealth of biodiversity is the product of hundreds of
millions of years of evolutionary history. The
process of evolution means that the pool of living
diversity is dynamic and constantly changing.
Climatic, geologic, hydrologic, ecological and
evolutionary processes generate biodiversity and
keep it forever changing (Noss and Cooperrider
1994). We explore this issue with more details in
Chapter 4 - Succession and Disturbances.
Levels of Biodiversity
Let's explore in more detail how biodiversity
occurs in ecosystems. The key to an effective
analysis of biodiversity is the definition of each level
of organization that is being addressed.
Biodiversity is usually considered at three
different nested levels: 1) gene, 2) species and 3)
ecosystem. Changes in one level of biodiversity may
have impact on the next level and vice-versa. For
example, imagine that an exotic disease (Dutch elm
disease or Chestnut blight) is introduced to an urban
forest with low species diversity (mostly elms or
chestnut trees). Since the genetic pool of these urban
forests is limited to species susceptible to these
diseases, not only individual species will be affected
but also the whole ecosystem to which these species
belong.
Gene level
Biodiversity at the genetic level refers to the
information contained in the genes of all individual
plants, animals and microorganisms. This level of
biodiversity is critical in order for species to adapt to
changing conditions and to evolve.
Restoration ecologists usually recognize the
genetic level of biodiversity in restoration projects.
For example, after Hurricane Andrew struck in South
Florida in 1992, all the Australian pines (
Casuarinaequisitifolia
) were destroyed in Bill Baggs, a heavilyused urban park in Miami. Prior to the hurricane,
Australian pine, which is a highly invasive species,
covered a large portion of the park. The natural
removal of Australian pines by the Hurricane
provided a great opportunity to restore the park to
conditions closer to its previous natural conditions.
In this project, it was recommended that seeds be
collected from local ecosystems within 50 miles
radius of Bill Baggs in order to ensure a well-adapted
genetic pool to the climate and soils of this specific
location
(Figure 2).Species level
This level is what most people have in mind
when they think about biodiversity. Most simply,
species diversity is the number of species present in
an area. However, the specific combination of
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 3
Figure 2.1 Photo by Mary Duryea
Figure 2.2 Photo by Mary Duryea
Figure 2.
The Bill Baggs Cape Florida RestorationProject, considered the genetic level of biodiversity by
collecting genetic material from areas representative of
the region's ecosystems. Several small ecosystems were
restored including wetlands (2.1), and uplands (2.2).
species and their relative abundance are also
important considerations.
It is common in many cities across the US to
find neighborhoods where streets are all planted with
the same tree species. In fact, if we consider even
the whole city, we would find only a few species
planted over and over again. The diversity of street
tree species is critically low in many U.S. cities and
towns (Sun 1992). In Oakland CA, for example,
only four species make up 49 percent of the tree
population (Nowak 1993), and in Chicago IL, six
species or genera constitute more than half of the
population (Nowak 1994).
A classic example of problems associated with
lower species diversity is the extensive use of
American elm (
Ulmus americana) as a street andurban tree in U.S. cities after World War II.
American elm constituted 95 percent of all street
trees (200,000 elms) in Minneapolis MN, for
instance (Price 1993). When Dutch elm disease, a
fungus spread by bark beetles that causes wilting and
dieback of elms, was introduced in the late 1960's,
nearly all American elms were killed in Minneapolis
and in the rest of the country
(Figure 3). Besides theobvious aesthetic problems, this lack of biodiversity
necessitated major and expensive efforts to eradicate
and dispose of the killed elm trees.
Figure 3.1 Photo by Mary Duryea
The Dutch elm disease outbreak and the loss of
virtually all American elms illustrate the
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 4
Figure 3.2 Photo by Edward Gilman
Figure 3.
American elms (Ulmus americana), were onceextensively planted in streets and parks in many cities and
towns across the U.S. (3.1). The introduction of Dutch elm
disease killed nearly all the elms (3.2) and reminds us that
the species level of biodiversity is critical when managing
urban forests.
consequences of lack of species diversity. Besides,
by planting only a few tree species or genera, the age
diversity of the species planted may be extremely
reduced. The end result of this practice is many old,
decaying trees to be removed, pruned and managed
at the same time, increasing the city's or
municipality's tree maintenance costs.
Biodiversity can be enhanced at the species
level by simply increasing the number of different
tree species planted (preferably native species
present in natural ecosystems in the region).
Additionally, by planting species each year instead of
all in one year, the age diversity in urban forests can
also be increased.
Ecosystem level
The structure of the urban forest is an important
biodiversity consideration at the ecosystem level.
Structure in forests is characterized by the nature and
abundance of the various vegetation layers (canopy,
subcanopy, shrub layer and ground cover) and the
presence of dead logs and snags. It is important that
ecosystems retain their natural structure.
In most ecosystems, a greater structural
diversity will support a greater diversity of wildlife
and will ensure better ecosystem functioning. A
forested ecosystem should have snags (dead standing
trees)
(Figure 4) and logs (Figure 5), which providehabitat for small mammals, amphibians and reptiles
and food for many insects and fungi (which in turn
are food for birds).
Figure 4.1
Structural diversity should be reintroduced in
restoration projects. There are several ways in which
this can be accomplished. For example, a snag can
be created by cutting a hazard tree but leaving a taller
stub to decay. Many urban forest restoration projects
also import logs and snags by salvaging trees in areas
slated for development. These trees are then used as
either downed logs or "planted" back in the ground
like giant posts to decay, increasing the structural
diversity and enhancing nutrient cycling.
Why Is Biodiversity Important?
Recently, all natural ecosystems on earth have
been estimated to provide
$33 trillion annually inecosystem services (Costanza
et al. 1997). This istwice the combined gross domestic product of all
nations in the world. Ecosystem biodiversity
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 5
Figure 4.2
Figure 4.
Snags provide important ecosystem structure.They are habitat for birds (4.1), mammals, termites,
insects, frogs and several microorganisms and are also
important for the nutrient cycle (4.2).
Figure 5.
In a natural forest, there will be snags and logsin different stages of decay. Different living organisms use
these different stages.
provides us with these services, which include the
protection of water resources, nutrient storage and
cycling, pollution bioremediation (biologically based
environmental cleanup), maintenance of ecosystems,
soil formation, climate regulation and other natural
processes, recreation and food production.
Biodiversity occurs at several spatial scales
(locally, regionally, globally). This means that
biodiversity has significance at a global scale as well
as in our own city backyards. Some of the values
associated with biodiversity include:
• ecosystem functioning,
• future value, and
• educational and recreational benefits.
Ecosystem functioning
When ecosystems are diverse, there is a range of
pathways for many ecological processes and for
primary production. If one of these pathways is
damaged or destroyed, an alternative pathway may
be used and the ecosystem can continue functioning
(Kimmins 1996). For example, when a particular
bacteria species is missing from the nutrient cycle, in
a diverse ecosystem, another organism may be
present to carry out the same function
(Figure 6).However, some organisms, such as top predators,
also play an important role in ecosystem functioning
but cannot be easily replaced. In any case, if the
biological diversity is greatly diminished, the
functioning of the ecosystem may be at a risk.
The associated costs of losing the ability of
ecosystems to function are extremely high. The
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 6
Figure 6.
An example of ecosystem services is thedecomposition of organic matter by microorganisms and
other species, such as these fungi. Photo by Larry Korhnak
degradation of wetlands is a dramatic example of the
problems associated with loss of ecosystem
biodiversity. Floods, problems in water quality and
quantity for natural and human systems, and declines
in fish and wildlife populations, have all been linked
to wetlands destruction, degradation and
fragmentation. The Everglades is an extensive
ecosystem in Florida which currently faces such
problems. Costs for restoring natural ecosystem
services and biodiversity to the Everglades have been
estimated to be hundreds of million of dollars.
Congress recently approved the expenditure of $1.5
billion to restore only some areas of the Everglades
(South Florida Ecosystem Task Force 1998).
Future value
Natural ecosystems are a reservoir of continually
evolving genetic material, irrespective of whether
their values have been recognized. The same genetic
material may have important but yet to be discovered
medicinal, economic, aesthetic, recreational or
intrinsic values for future generations.
An example of one of the most promising
discoveries in recent years has been taxol, which was
initially isolated from the Pacific yew (
Taxusbrevifolia
Nutt.), a tree species in the Douglas-firforests of the Pacific Northwest that was until
recently considered unimportant
(Figure 7). Taxolhas been used in the treatment of ovarian and breast
cancers. In the U.S., approximately 25% of all
prescriptions contain active ingredients derived from
plants (Principe 1989).
Figure 7.
The bark of Pacific yew (Taxus brevifolia Nutt.)trees contains taxol, a new drug for treating several forms
of cancer. Photo by Dr. AC Mitchell
Biodiversity is also essential in biological
control and for the breeding of disease resistant
species. Use of genetically resistant plant species for
food production, clothing, commercial and urban
forestry is derived from a wide array of diverse
native species.
Educational and recreational benefits
One of the most important reasons to manage
and protect biodiversity in urban centers is their
educational and recreational values. Recreational
benefits are perhaps the most important value of
biodiversity in urban areas. People value natural
areas for a variety of reasons: psychological
renovation through contact with nature, jogging and
hiking, birdwatching, photographing, and many
other activities. The aesthetic value of ecosystems
also contributes to the emotional and spiritual
well-being of a highly urbanized population
(Figure8)
.Figure 8.1 Photo by Mario Binelli
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 7
Figure 8.2 Photo by Mario Binelli
Figure 8.
Recreational benefits of biodiversity are closelyrelated to aesthetic, psychological (8.1 and 8.2) and
educational values.
In 1991, 30 million Americans participated in
wildlife watching and another 14 million adults went
fishing (U.S. Fish and Wildlife Service 1992).
Nationwide, wildlife viewers spent $18 billion
(Norris 1992). Watchable wildlife recreational
activities provide local economies with important
income generated by sales, employment and tax
revenues. For example, Florida's watchable wildlife
generated $3.5 billion in 1996 (Florida Game and
Fresh Water Fish Commission 1998).
Some ecosystems, especially those close to
metropolitan centers are becoming extremely rare.
For example, Florida's scrub ecosystems are now
surrounded by the greater Orlando urban area and are
threatened by human encroachment and
development. Ultimately, it will be up to these urban
citizens to protect such ecosystems and their benefits.
In this case, there is some evidence that the Florida
scrub jay, an endangered bird in the scrub ecosystem,
may persist in residential areas, provided adequate
patches of the scrub ecosystem remain preserved
nearby. (Florida Game and Fresh Water Fish
Commission 1997). These urban remnant
ecosystems could be powerful tools for educating
urban citizens about the importance and value of
such diverse ecosystems
(Figure 9).Figure 9.1
Figure 9.2 Photo by Larry Korhnak
Figure 9.
Managing for biodiversity in urban areas is anexcellent opportunity for integrating ecological,
educational (9.1) and recreational values (9.2).
Increasing urbanization accelerates human
pressures on remaining natural ecosystems. At the
same time, however, recreational spaces have to be
managed for this increasing population. In 1996, 2.7
million Floridians participated in wildlife
recreational activities within a mile of their homes
and 543,000 visited natural areas around their homes
(Florida Game and Fresh Water Fish Commission
1998). Urban forests may play an important role in
integrating recreational demands and conservation of
natural resources.
Now that we have discussed some values of
biodiversity,
why should urban managers considerbiodiversity in the restoration of urban forests as
ecosystems?
Urban and community forests havebeen estimated to provide nationwide $3 billion a
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 8
year in social, ecological and economic benefits
(McPherson and Rowntree 1991). These benefits
include conservation of energy, pollution control,
and improvement of aesthetic quality of cities. By
managing and restoring urban forests for biodiversity,
such benefits could be greatly enhanced. For
example, by restoring ecosystems and their
associated natural processes, such as nutrient and
hydrological cycling, local communities could save
money, energy and resources. Restoring an urban
wetland to provide habitat for wildlife would also
contribute to recreational and economic
opportunities. Removal of invasive species from a
city's park, for instance, may bring back the natural
diversity and functioning of the ecosystem, which in
turn might improve its recreational and aesthetic
value for the local community.
Managing for biodiversity in urban areas will
require a more holistic approach than usually seen.
Urban forests are more than a collection of street
trees. Remnants of natural areas, waterways, parks,
backyards, right-of-ways and industrial parks both in
public and private properties are all part of the urban
forest ecosystem.
Can Biodiversity Be Protected In
Urban Forests?
Most human-made habitats, such as a
landscaped park, have lower biodiversity than natural
forests. However, urban environments usually
include a great diversity of habitats (such as water
retention ponds, industrial parks, railway
rights-of-way, greenways, and others) which may
support some wildlife and plant species. In some
cases, urban habitats may even play a significant role
in the conservation of 'rare' or 'threatened' species.
For example:
1. Rare prairie plant species in the Midwestern US
are found alongside railroads and highways. In
such areas these species are protected from the
agricultural activities that destroyed much of the
original prairie habitat (Ahern and Boughton
1994).
2. Of the 144 threatened and endangered wildlife
species of Illinois, 14% (20 species) have been
recorded in recent times in Cook county, the
most urbanized county of the Chicago
Metropolitan area (Friederici 1997).
How Is Biodiversity Reduced In
Urban Areas?
The ultimate threat to global biodiversity is an
increasing human population and the consequent
increased use and development of the world's
remaining natural ecosystems. The largest threat to
biodiversity in urban areas is the reduction and
alteration of the total area of natural ecosystems
available to native animal and plant species
(Figure10)
. Ecosystem destruction, degradation andfragmentation may significantly reduce biodiversity.
Figure 10.1
Ecosystem destruction
Frequently, urban natural areas are completely
eliminated during residential and/or commercial
development. Usually, after construction exotic
trees, shrubs and lawns are established. Additional
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 9
Figure 10.2
Figure 10.3
Figure 10.4
Figure 10.
Biodiversity is lost by ecosystem destruction(10.1), fragmentation (10.2) and degradation. Figure 10.3
illustrates a degraded longleaf pine ecosystem that has
been invaded by exotic species whereas figure 10.4
illustrates a healthy longleaf pine ecosystem. The diversity
of the longleaf pine ecosystem is associated with its
herbaceous layer and a relatively open canopy.
amounts of fertilizers and irrigation, frequent
mowing and mulch are required for such intensively
managed areas.
If instead natural areas are preserved and
incorporated during development, biodiversity could
be maintained. Natural areas have much lower
maintenance requirements when compared to
traditional landscaping. Additionally, aesthetically
pleasing environments, such as natural urban
remnants, increase the economic value of residential
and commercial areas.
Ecosystem degradation
Ecosystem degradation may not be easily
noticed in the short-term and is difficult to detect and
harder to quantify. Degradation is of greater
long-term concern, since its effects are cumulative
and may build up only very slowly. Degradation
deteriorates and disrupts ecosystem processes. Some
examples of causal degrading agents are pesticides,
chronic air pollution and invasive species. Erosion,
or removal of the litter from a forested site would
also cause ecosystem degradation by interrupting
nutrient cycling.
Microorganisms in the soil (such as
invertebrates, fungi and bacteria) carry out critical
ecosystem functions (such as decomposition and
nitrogen fixation). Yet these organisms are so small
that they usually go unnoticed until the consequences
of their disruptions are too obvious to neglect.
In metropolitan centers, for instance, air
pollutants slowly accumulate in urban forest soils
over time. The gradual accumulation of
hydrocarbons in a New York urban forest, for
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 10
example, formed a hydrophobic soil layer, which in
turn, has decreased the population and activity of soil
microbes and invertebrates. This hydrophobic layer,
coupled with trampling and high concentrations of
heavy metals in urban soils, have also reduced the
rates of microbial processes, affecting the nitrogen
cycle in these forests (White and Mc Donnell
1988).
Ecosystem fragmentation
Landscapes become fragmented when natural
ecosystems are broken up into remnants of
vegetation that are isolated from each other
(Figure11)
. Therefore, fragmentation results in a landscapethat consists of remnant areas of native vegetation
surrounded by other land uses. At a larger scale the
landscape is composed of cities, farms, rivers, rural
areas and natural areas
(Figure 12). In the urbanarea the landscape might include strips of street trees,
backyards, schoolyards, shopping centers, creeks,
rivers, parks, landfills, industrial parks and fragments
of natural areas
(Figure 13).Figure 11.
In urban areas, ecosystems that used to becontinuous are now fragmented in the landscape.
Figure 12.1 Photo by University of Florida, Map and
Imagery Library.
Figure 12.2
Figure 12.
At a larger scale, the landscape is composedof cities (12.1), farms, rivers, rural areas, natural areas and
fragments of natural areas (12.2).
Ecosystems are Connected and
Inter-related
The landscape is a mosaic of several different
ecosystems. It is important to recognize that natural
ecosystems are connected and inter-related.
Fragmentation of natural ecosystems will affect
ecosystem processes, plants, and wildlife. Turtles, for
example, live in water but need upland ecosystems to
lay their eggs. If we fragment upland ecosystems, by
either constructing a road between the ecosystems or
putting a fence around the upland, turtles will be
prevented from reproducing
(Figure 14).This example shows that we need integrated
management and restoration efforts, where
ecosystems are allowed to interact with each other.
Roads, fences or other human-made boundaries may
limit the flow of nutrients and water and the
movement of plants and animals between ecosystems.
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 11
Figure 13.1
Figure 13.2
Figure 13.3 Photo by Paul West, Seattle Department of
Parks and Recreation
Figure 13.
In urban areas, the landscape is composed ofstreet trees (13.1), backyards, shopping centers (13.2),
parks, industrial parks and fragments of natural areas
(13.3).
Figure 14.
This yellow bellied turtle (Trachemys scripta)was stranded by a road while trying to move to an upland
ecosystem to lay eggs. This usually happens when the
interconnectedness of ecosystems is not taken into
account. Photo by Joseph Schafer
What happens to ecosystem
fragments?
Let's take a closer look at an ecosystem that has
been fragmented and isolated. Usually, conditions in
the surrounding landscape are different from
conditions in the ecosystem fragment. As a result, an
edge is formed between the landscape and the
ecosystem fragment. Every ecosystem has an edge,
but the amount of edge in urban ecosystem fragments
increases tremendously as a result of external factors
in the landscape. As the edge increases, the size of
the interior core is reduced.
The core area of an ecosystem fragment is the
undisturbed interior area of that ecosystem. In this
core area we usually have:
• functional ecological processes,
• a greater diversity of native species,
• a diversified structure with multilayered
vegetation (trees, shrubs, herbaceous and ground
cover plants), logs and snags,
• a greater diversity of wildlife with
area-sensitive birds, mammals, and other
animals, and
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 12
• an undisturbed microclimate.
Several external factors from the landscape can
affect ecosystem fragments
(Figure 15). Along theedge of the ecosystem fragment there is increased
solar radiation. Since there is more light available,
species that grow better in full sun will become
established closer to the forest edge while shade
tolerant species will be restricted to the interior core
(Saunders et al. 1991). Invasive species will also be
favored in edges and more disturbed areas.
Figure 15.
External factors from the landscape affectecosystem fragments. The greater these external
influences, the greater the edge and smaller the core area.
Trees at the edge will also be more susceptible
to wind, air pollution and increased temperatures,
resulting in a drier microclimate (Saunders et al.
1991). In turn, nutrient cycling may be affected
because the heating of the soil may affect
microorganisms, litter decomposition, and soil
moisture retention.
Therefore, fragmentation alters the structure,
composition and function of ecosystems. A principle
to remember is that the more you alter the structure,
composition and function of ecosystems, the greater
the energy needed to restore the ecosystem back to
its original condition.
One example is Forest Park, a 5,000-acre urban
park in Portland, Oregon. This park is an ecosystem
fragment that has been greatly impacted by the
surrounding land uses. The neighboring
communities landscape their yards with English ivy
(
Hedera helix), an invasive and aggressive species.By bird dispersal and vegetative growth, English ivy
has spread and invaded this forest
(Figure 16).English ivy alters the structure of the forest (by
impeding the growth and development of native
plants), its composition (now there is only English
ivy underneath the canopy) and, consequently, this
ecosystem's functioning (alteration of nutrient
cycling, since decomposition of organic matter may
be affected). The amount of energy required to
restore this ecosystem is tremendous. It is an
ongoing effort, but as a result, native species are
regenerating and biodiversity is slowly coming back
to Forest Park.
Figure 16.
These high school students are removingEnglish ivy, an invasive species that completely took over
Forest Park, an urban park in Portland, Oregon. Photo by
Mary Duryea
How Can Buffer Zones Help?
Buffer zones are semi-natural areas located
around areas of higher natural values, such as core
areas. A buffer zone around an ecosystem fragment
will minimize external influences and help maintain
the ecological integrity of the ecosystem's core area.
Establishment of buffer zones around natural and
semi-natural areas permits integration of human land
uses while still managing for biodiversity
(Figure17)
.Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 13
Figure 17.
Buffer zones in urban settings can minimizeexternal influences of the surrounding landscape and
maintain the ecological integrity of urban ecosystem
fragments.
How does fragmentation affect
biodiversity?
Fragmented ecosystems are isolated and in urban
areas the distance between fragments may be large.
This, coupled with the increase in edge area and
reduction of the core area, will decrease flow of
genes and seed dispersal. Animals and plants that
used to be in the whole area are now restricted to
smaller patches.
Connected ecosystems or unfragmented
landscapes will have a greater diversity of native
species
(Figure 18), due to their larger core area, alower edge:core area ratio and less isolation
(compared to smaller fragments).
Figure 18.
The greater the area, the greater the numberof species in the ecosystem (adapted from MacArthur and
Wilson 1967).
Let's examine the consequences of
fragmentation on bird populations. Area sensitive
birds, such as flycatchers, vireos and warblers, will
be reduced with fragmentation and reduction in core
area. Area sensitive birds are those that need a large
undisturbed area and hence would only live in the
interior core area of a large fragment (Adams and
Dove 1989)
(Figure 19.1). Habitat generalist birdscan be quite common in more urbanized areas and
may thrive in many different conditions. Cardinals,
jays, house wrens, and catbirds are examples of
habitat generalist birds
(Figure 19.2).If we want to enhance the diversity and the
presence of area sensitive birds in urban areas, we
need to restore and connect core areas of ecosystems
(for more information on wildlife, see
Chapter8-Wildlife
).Figure 19.1 Photo by Thomas G. Barnes
How Can We Connect Fragmented
Ecosystems In The Urban
Landscape?
The search for solutions to the problems of
ecosystem loss, degradation and fragmentation has
led to a growing number of new projects and
solutions. Most projects are based on ecologically
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 14
Figure 19.2 Photo by Thomas G. Barnes
Figure 19.
Area sensitive birds, such as certain types ofowls (19.1) may have their diversity reduced with
fragmentation and a reduction in core area. However,
habitat generalist birds, such as common sparrows (19.2)
may be favored in a patchy environment.
sound principles. Basically, we attempt to connect
fragmented ecosystems in the urban landscape and
manage the landscape as a whole. By doing so, the
distance between ecosystems fragments will be
shortened, improving connectivity of isolated
fragments.
Connectivity is essentially the opposite of
fragmentation. Instead of breaking landscapes into
pieces we are seeking ways to restore broken
connections between fragmented ecosystems
(Figure20)
.Figure 20.1
Figure 20.2
Figure 20.
In Figure 20.1, patches A and B used to be partof the same contiguous ecosystem. A corridor may
provide linkage between these ecosystem fragments.
Riparian coridors (20.2) are landscape linkages that may
connect several ecosystem fragments in the urban-rural
interface.
Effective connectivity is measured by the
potential for movement and flow of genes, that is,
movement and migration of animals (especially
birds) and dispersal of plants. Many factors
determine the effectiveness of connectivity, and it
varies depending on the ecosystem of interest.
Usually, effective connectivity will depend on:
• presence of barriers (e.g., fences which would
limit migration),
• distance between ecosystem fragments,
• amount of edge in the landscape linkage,
• nature of the surrounding landscape, and
• species which will benefit from promoted
connectivity (e.g., whether a bird,a mole, a
plant).
Connectivity can be promoted by using
corridors, greenways, and stepping stones.
Corridors
Corridors are strips of natural vegetation linking
ecosystem fragments. They can be defined as "any
area of habitat through which an animal or plant
propagule has a high probability of moving" (Noss
1991). Preserves or fragmented ecosystems with
high biodiversity level or rare species may be linked
by corridors
(Figure 21).Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 15
Figure 21.
This corridor may be serving as linkage forbirds between fragmented ecosystems. Photo by Henry
Gholz
Whether corridors will provide all or none of the
benefits listed in
Table 1, will depend on severalfactors. For instance, a corridor that has a high
proportion of edges compared to the interior forest
may facilitate spread of pests, diseases and
catastrophic fires or increase exposure of wildlife to
predators and domestic animals.
Table 1.
Benefits and disadvantages of ecologicalcorridors.
BENEFITS DISADVANTAGES
enhance biotic movement
(because they permit flow
of genes)
spread of diseases
provide extra foraging
areas for species that
require more resources
than those available in a
single patch
increased predation
provide wildlife plant
habitat
Groups of corridors can be combined to form
corridor networks. By adding several corridors and
integrating them with buffer zones and natural
preserves, connectivity may be increased
(Figure 22).Figure 22.
The proposed network of natural areas, bufferzones and corridors forms a bigger regional network of
ecosystems for the state of Florida. This corridor network
connects two important waterways, Ockefenokee (North
Florida) and Everglades (South Florida), which have been
disconnected for decades.
Many restoration projects in cities begin with
river connections. Why are rivers and creeks
considered good linkage corridors? First, because
riparian ecosystems are considered to be one of the
richest habitat types, with alluvial soils, abundant
insects and plant species. They constitute one of the
most biologically productive and diversified habitat
types with complex and multilayered vegetation (see
Chapter 6 - The Hydrologic Cycle
). Second, riversand creeks are natural corridors which pass through
many ecosystems, so the linkages between these
ecosystems already exist.
Greenways
Greenways are a type of corridor designed to
connect open spaces for ecological, cultural and
recreational purposes. There are a wide variety of
greenway projects around the country. We can find
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 16
greenways projects that are managed as corridors
between natural areas (with an ecological objective)
and others that are for purely recreational purposes.
Greenways range from narrow urban trails to
winding river corridors to very wide, landscape level
linkages.
It is important to define the goals of greenways.
In some instances, an urban greenway restricted to a
very narrow width, creating a beautiful space for
recreation, may be the primary goal
(Figure 23).However, relatively few greenways have been
designed with detailed consideration of ecological
functions (Smith and Hellmund 1993). Nonetheless,
a greenway's ecological function should be
considered and promoted whenever possible. An
example is the Rio Grande Valley State Park in New
Mexico. This park is a heavily used urban recreation
area located only 2 to 3 miles from downtown
Albuquerque, NM. The park contains extensive
riparian forests of native cottonwood (
Populusdeltoides
) and black willow (Salix nigra). Theseforests contrast with the typical arid Southwest areas
surrounding them and for this reason host a high
diversity of wildlife and migratory birds.
Figure 23.1 Photo courtesy of Rio Grande Valley State
Park
Figure 23.2
Figure 23.
Some greenways, such as the Rio GrandeValley State Park in New Mexico (23.1), provide better
ecological function than this bicycle trail (23.2) in Florida.
Rio Grande Valley is a heavily used urban park that also
provides connectivity for wildlife and ecosystems.
Although activities like hiking, horseback
riding, picnicking, and nature walks are encouraged,
the Rio Grande Valley State Park gives high priority
to recreational trail design in order to protect
sensitive and unique habitats. Degraded areas have
been restored with native trees and shrubs, following
removal of saltcedar (
Tamarix spp.), an invasivespecies. Connectivity between high quality areas for
wildlife movement also have high priority. This
greenway effort seeks to restore natural species and
ecosystems processes, but also recognizes the need to
make resources available and enjoyable for people.
Stepping Stones
As mentioned before, viewing the landscape
holistically, instead of focusing on each separate area
in isolation, should be the objective of urban
managers. Even where it is not possible to connect
ecosystems through corridors, stepping stones can be
provided. Stepping stones (Franklin 1993) are
smaller habitats that permit some plants and animals
to move across the landscape from one ecosystem
fragment to the other
(Figure 24). Some interiorspecies, such as many native birds, may not find
them useful, but for some other species, such as small
mammals and reptiles, the connectivity enhances
habitat.
The minimum ideal size for ecosystems to
remain fully functional is often unknown. However,
some scientists theorize that an optimum landscape
has large patches of natural vegetation supplemented
with small patches scattered as stepping stones
throughout the landscape (Franklin 1993, Noss 1991,
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 17
Figure 24.
Stepping stones or small patches ofecosystems may help some species move from one larger
ecosystem fragment (A) to another (B).
Adams 1994). In summary, stepping stones provide
habitat for species that will live in small areas and
help the flow of genes so birds and some plants will
be able to move across the landscape.
How Can We Restore Biodiversity In
Urban Areas?
There are numerous ways to enhance
biodiversity in parks, neighborhoods, abandoned
areas, backyards, industrial zones and other urban
forest restoration projects, including:
• leaving stumps, leaves, snags and logs on-site
to enhance the ecosystem's natural structure,
maintain the nutrient cycle, and provide habitat
for wildlife and other organisms,
• planting native species in combinations that
mimic nearby ecosystems,
• controlling invasive plants and animals which
may eliminate native species,
• enhancing the ecosystem's structural diversity,
and
• creating multi-age ecosystems (forests) in
several stages of ecological succession typical of
that ecosystem (see
Chapter 4 - PlantSuccession and Disturbances
).In these urban forest restoration projects, it is
essential to maintain and/or restore the ecosystem's
ecological processes, such as:
•
natural disturbances: such as fires and naturalhydroperiods (for instance, re-instating flooding
in drained wetlands),
•
ecological succession: understand ecologicalsuccession in nearby similar ecosystems and
consider establishing these successional stages
(for more information see
Chapter 4 - PlantSuccession and Disturbances
),•
nutrient cycle: promote and educate about theneed for retaining leaves, twigs, branches and
logs on site to store and cycle nutrients (see
Chapter 2 - Basic Ecological Principles
), and•
hydrological cycle: find ways to aid thehydrological cycle. Examples include leaving
natural mulched areas for better water
infiltration and maintaining vegetative cover to
prevent water erosion (see
Chapter 6 -Hydrologic Cycle
).Examples of Restoration Projects
There are many projects in cities and urban areas
that restore urban forests as whole ecosystem(s).
Biodiversity is often an important part of these
restoration projects, either at a small or large scale.
Reintroducing Fire in Gainesville, FL
Natural fire regimes are important ecological
processes that should be reintroduced in fire-adapted
ecosystems, including urban forest ecosystems.
For example, the longleaf pine ecosystem, a
natural forest type of the Southern US, is adapted to
periodic and light fires. Fires keep adjacent
hardwood species from invading longleaf pine
forests
(Figure 25.1). In the process, these firesmaintain an extremely diverse flora in the ground
layer
(Figure 25.2). There are more than 100herbaceous species in sites no larger than an acre and
at least 190 rare and endemic species associated with
this ecosystem (Hardin and White 1998). Fires are
essential to maintain this ecosystem's natural
structure, that is, an open canopy of longleaf pines
and the diverse ground layer. If fires are suppressed,
this unique flora is largely lost.
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 18
Figure 25.1
Figure 25.2
Figure 25.
Frequent but low intensity fires keep adjacenthardwood species from invading longleaf pine ecosystems
(25.1), and are essential to maintain these forests' natural
structure and ground layer biodiversity (25.2).
Fires have been reintroduced in remnants of
longleaf pine ecosystems in urban areas. An example
is a subdividion in Gainesville, FL, that contains
patches of a longleaf pine ecosystem interwoven with
houses, golf courses and streets. Periodic prescribed
fire is applied to these patches of longleaf pine,
maintaining its open canopy and rich herbaceous
species. Education plays a key role in such innovative
pratices in urban centers
(Figure 26).Figure 26.1
Figure 26.2
Northeast Anne Greenbelt Forest
Restoration in Seattle, WA
Downtown Seattle has a 35-acre restoration
project developed by the Seattle Department of Parks
and Recreation (SDPR), University of Washington
and the local community. This project is part of a
greater effort to apply integrated landscape
management practices in parks and other areas in the
Seattle region
(Figure 27).Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 19
Figure 26.3
Figure 26.
This subdivision in Gainesville, FL has patchesof a longleaf pine ecosystem (26.1) interwoven with
houses, golf courses and streets (26.2). Periodic
prescribed fire is applied to these patches. Education
plays a key role in such innovative practices in urban areas
(26.3).
Figure 27.
The Northeast Anne Greenbelt ForestRestoration is a neighborhood restoration project in
Seattle, WA (map at left). Other similar small scale
projects are funded and coordinated by the Seattle
Department of Parks and Recreation.
The site was heavily invaded by exotic invasive
species (English Ivy
, bindweed, Himalayanblackberry, and Scotch broom), ornamental plants
and weeds, and was also a dumping ground for trash.
Additional problems were soil erosion and lack of
wildlife.
The partners worked together and developed a
plan to:
• remove the exotic vegetation,
• plant varying native species to provide food
and cover for wildlife and to enhance structural
diversity,
• create logs and snags to provide habitat for
invertebrates, woodpeckers, and decomposers,
and
• plant trees with deep roots and understory
vegetation to help stabilize the soil and reduce
erosion.
Today, the area has been cleared of exotics,
erosion has been stabilized and an environmental
center has been established, where the local
community promotes educational and recreational
activities.
Chicago Wilderness in Chicago, IL
The Chicago Wilderness is a combined effort of
60 partnering organizations, including landowners,
local, regional and federal agencies, universities and
conservation agencies. The Chicago Wilderness'
primary goal is to restore ecological processes that
maintain biodiversity. Their work is to improve the
region's biodiversity at all levels: genetic, species
and ecosystem diversity throughout the landscape.
To meet this goal they have several objectives:
• to document the region's ecosystems,
• to help restore natural communities on public
and private lands,
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 20
• to prevent further loss of critical ecosystems
and, at the same time, promote carefully planned
development,
• to promote education, outreach and volunteer
opportunities, and
• to define restoration strategies (including
removal of aggressive invasive species, thinning
of native trees to promote growth of savannas
and woodlands species, use of prescribed fire
and planting of native species).
To date, there are over 109 Chicago Wilderness
collaborative projects ranging from biodiversity
initatives to prairie and savanna restoration projects
with prescribed burning to backyard biodiversity
initiatives to restoration of threatened and
endangered species
(Figure 28).Figure 28.
Outreach materials utilized by ChicagoWilderness educate citizens about the region's biodiversity
and strategies for restoration.
Monitoring Success
Monitoring is a crucial part of every ecosystem
restoration project. Monitoring provides the
opportunity to gather information about how
ecosystems in urban areas work and how ecosystems
and people interact over time. It is also a critical
activity for reevaluating the success or failure of
projects so that we can apply this accumulated
knowledge and experience to future projects.
Ecosystems are complex and inter-related and
even the best studied and planned projects might
have unexpected results. One example of a learning
experience is a salt marsh, 8 km south of downtown
San Diego, CA. The restored ecosystem was
supposed to provide habitat for an endangered bird,
the light-footed clapper rail (
Rallus longirostrisLevipes)
(Figure 29). Cordgrass species (Spartinaspp.) were transplanted from nearby wetlands to
provide nesting sites for the bird. However, the plant
did not grow to 90 cm, the bird's preferred height.
Researchers working on the project thought the
problem was due to the marsh's sandy, nutrient-poor
soil, so they added nitrogen fertilizers. But the
fertilizer favored another plant, pickleweed, which
outgrew the desired grass (Malakoff 1998).
Researchers are still trying to determine the best
methods for restoring this ecosystem.
Figure 29.
Since ecosystems are complex andinter-related, careful planning and monitoring are essential
elements of restoration projects. The example of this salt
marsh and the light-footed clapper rails reminds us that
there are no easy recipes. Photo by David Sarkozi
Conclusions
Urban forest ecosystems present many
opportunities for restoring biodiversity, whether in a
backyard, neighborhood, park or natural area. It is
essential to know and understand the natural
ecosystems in these areas in terms of vegetation,
structural diversity, wildlife, natural disturbance
regimes and the nature of their ecological processes.
When managing ecosystems for biodiversity, we
should pay attention to ecosystem structure and its
Chapter 3: Biodiversity and the Restoration of the Urban Forest Ecosystem 21
functioning. Ecological processes, such as nutrient
cycling, hydrological cycling, and ecological
succession should be reinstated in the urban forest
ecosystem as a comprehensive strategy for
biodiversity conservation.
Corridors, buffer zones, greenways, and
stepping stones are all ways in which urban forests
can be managed as ecosystems. While large scale
projects may help reestablish connectivity and
maintain important ecological processes, small scale
projects, such as removing invasive species or
restoring native species in a small city park, also
contribute.
However, management of the landscape as a
whole can only be accomplished if we take an
interdisciplinary and integrated approach toward
urban forests. This requires a combined and joint
effort of local, state and federal governments, as well
as private, public and grass-root initiatives.
Education plays a critical role in generating informed
citizens who are essential partners in the
establishment of restoration projects in cities.
Suggested Readings
Dunster, J. A. 1998. The role of arborists in
providing wildlife habitat and landscape linkages
throughout the urban forest. Journal of
Arboriculture, 24(3): 160-167.
Argent, R. M. 1992. Ecological succession as a
criterion for the selection of urban trees.
Dissertation, Texas A&M University. 80p.
Sun, W. Q. 1992. Quantifying species diversity
of streetside trees in our cities. Journal of
Arboriculture, 18(2): 91-93.
Cited Literature
Adams, L. and L. E. Dove. 1989. Wildlife
reserves and corridors in the urban environment: A
guide to ecological landscape planning and resource
conservation. National Institute for Urban Wildlife,
Columbia, MD. 87p.
Adams, L. W. 1994. Urban wildlife habitats: A
landscape perspective. University of Minnesota
Press, Minneapolis, MN. 186p.
Ahern, J. and J. Boughton. 1994. Wildflower
meadows as suitable landscapes. In: Platt, R.H.,
Rowntree, R. A. and Muick, P. C. (eds), The
ecological city: Preserving and restoring urban
biodiversity. pp 172-187, University of
Massachusetts Press, Amherst.
Costanza, R., R. d'Arge, R. de Groot, Farber, M.
Grasso, B. Hannon, K. Limburg, S. Naeem, R. V.
O'Neill, J. Paruelo, R. G. Raskin, P. Sutton and M.
van den Belt. 1997. The value of the world's
ecosystem services and natural capital. Nature,
387(6630): 253-258.
Florida Game and Fresh Water Fish
Commission. 1997. The Florida scrub jay.
Tallahassee, FL.
Florida Game and Fresh Water Fish
Commission. 1998. The 1996 Economic benefits of
watchable wildlife recreation in Florida.
Tallahassee, FL.
Franklin, J. F. 1993. Preserving biodiversity:
species, ecosystems or landscapes? Ecological
Applications, 3(2): 202-205.
Friederici, P. 1997. Where the wild ones are.
Chicago Wilderness Magazine, Fall 1997: 6-9.
Hardin, E. D. and D. L. White. 1989. Rare
vascular plant taxa associated with wiregrass
(Aristida stricta) in the Southeastern United States.
Natural Areas Journal, 9:234-245.
Keystone Center. 1991. Biological diversity on
federal lands: Report of a keystone policy dialogue.
The Keystone Center, Keystone Co., 96p.
Kimmins, J. P. 1996. Forest ecology: A
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Chapter 4: Plant Succession and Disturbances in the
Urban Forest Ecosystem1
Eliana Kämpf Binelli, Henry L. Gholz, and Mary L. Duryea
21. This is Chapter 4 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Eliana Kämpf Binelli, Extension Forester, Henry L. Gholz, Professor, and Mary L. Duryea, Professor and Extension Forester, School of Forest Resources
and Conservation, Institute of Food and Agricultural Sciences, University of Florida, PO Box 110410, Gainesville, FL 32611
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Ecosystems are dynamic. Disturbances lead to
changes in ecosystems, collectively called
succession. Disturbances can be natural and/or
anthropogenic (human-caused). Natural
disturbances, such as wildfire, play an important role
in forest succession. Knowledge of natural
disturbance regimes is important to maintaining
biodiversity. In forest succession, species
composition, ecosystem structure and ecosystem
functioning all change gradually over time. In urban
areas, the alterations of natural disturbance regimes,
along with the introduction of invasive species have
altered natural succession. Natural disturbances vary
in spatial scale (from small to large areas) and
temporal scale (from hours to eons). Variation in the
temporal and spatial scales of disturbances leads to
ecosystems spread over the landscape that are in
different successional stages. This landscape
diversity meets the needs of a variety of wildlife
species. In order to restore more natural successional
regimes, we have to learn about ecosystems: their
natural disturbance regimes, their expected stages of
succession, and how they fit into the overall
landscape. Small scale urban forestry projects should
incorporate the concepts of succession, while
eliminating invasive species and re-introducing
natural disturbances regimes. Large scale projects
can also adopt these strategies, but have the
additional opportunity to manage for several stages
of succession across the landscape and to restore
missing stages of succession.
Change
A common misperception is that nature is in an
unchanging balance. However, natural scientists have
found strong evidence against this idea and we now
know that change is one of the most fundamental
characteristics of natural ecosystems.
Since trees generally live much longer than
humans, the forests they are in were also perceived
as unchanging. But, in fact, forests are highly
dynamic. In many forests, wildfires, floods,
windstorms or insect infestations produce major, but
infrequent changes. In other forests, change is more
subtle: single trees die and are replaced while most
trees remain alive. However, since individual trees
can live a long time, it is difficult to see or measure
changes in forests over short periods of time.
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 2
There are two related aspects of change over
time in forests:
disturbances and succession.Disturbances lead to subsequent changes in
ecosystems, which are collectively called succession.
This chapter discusses the dynamic nature of
forest ecosystems and why it is important to
understand disturbances and succession in order to
manage and restore urban forest ecosystems
successfully.
Disturbances
What are disturbances?
Disturbances are any event, either natural or
human-induced (anthropogenic), that changes the
existing condition of an ecosystem. Disturbances in
forest ecosystems affect resource levels, such as soil
organic matter, water and nutrient availability, and
interception of solar radiation. Changes in resource
levels, in turn, affect plants and animals over time,
leading to succession.
Disturbances occur in all ecosystems. We often
think disturbances result only from human activity.
However, the definition of disturbance should not
carry a connotation of negative human impact;
naturally occurring disturbances are part of every
ecosystem on earth.
What types of disturbances affect forests?
All forests are subjected to both natural and
anthropogenic disturbances. Examples of naturally
occurring disturbances include wildfires, winds
(hurricanes, tornadoes and windstorms), insect and
disease epidemics, landslides, ice storms, floods and
droughts (
Figure 1).Figure 1.1 Photo by Larry Korhnak
Figure 1.2 Photo by Larry Korhnak
Figure 1.
Historical fires (1.1) and natural hydroperiods(1.2) are examples of naturally occurring disturbances
which have been virtually eliminated from urban forest
ecosystems.
Examples of anthropogenic disturbances include
pollution, conversion of forests to nonforest areas,
timber harvesting, prevention of wildfires, global
warming, alteration of natural hydroperiods
(flooding), application of herbicides, introduction of
exotic species, litter raking, trampling and
compaction, fertilization and irrigation (
Figure 2).Figure 2.1 Photo by John Rieger, CA Department of
Transportation
The urban forest ecosystem is also subjected to
anthropogenic and natural disturbances. However,
natural disturbances, such as wildfires and normal
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 3
Figure 2.2 Photo by Larry Korhnak
Figure 2.
Conversion of forests to development (2.1) andraking of litter (2.2) are examples of anthropogenic
disturbances in urban forest ecosystems.
flooding periods, have been virtually eliminated from
urban forest ecosystems
(Table 1).Table 1.
Types of disturbances that occur or have beeneliminated from urban forest ecosystems (UFE's)
TYPES OF DISTURBANCES THAT OCCUR
MOST OFTEN IN UFEs
• removal of topsoil and soil grading
• air and soil pollution
• litter raking
• introduction of invasive species
NATURAL DISTURBANCES THAT HAVE
BEEN ELIMINATED FROM UFEs
• natural fires
• normal periodic flooding
• nutrient cycle
The focus of this chapter will be on naturally
occurring disturbances and their importance to
ecosystems. Ideally, restoration should return a site to
a condition that includes a natural disturbance
regime, but it may also be aimed at minimizing those
anthropogenic disturbances that are considered
undesirable.
The Importance of Natural Disturbances:
Yellowstone and the Suppression of
Wildfires
Fire may be the most widespread natural
disturbance in the world's forest ecosystems. In fact,
many forest and wildlife species persist because of
periodic fire disturbance. However, the perspective
that all disturbances are abnormal led to the Smokey
the Bear syndrome where all forest fires were
perceived as bad.
A classical example of the consequences of fire
suppression is the 1988 catastrophic fire that swept
through Yellowstone National Park, killing much of
its vegetation. The natural cycle of fire disturbance in
the park had been interrupted for more than one
hundred years by intentional fire suppression. This
led to a dense invasion by shade-tolerant trees and
understory vegetation, and excessive accumulation of
litter and woody debris in the forest, which
eventually caused rampant, intense and impossible to
control wildfires
(Figure 3).Why are disturbances important?
Disturbances are the norm for forest ecosystems.
Completely undisturbed forests are extremely rare or
even nonexistent.
The role that natural disturbances play in forests
is one of renewal. Whether the disturbance is big or
small, mild or intense, it plays an important role in
determining a forest's succession
(Figure 4).Disturbances initiate succession in ecosystems by
killing some or all individuals (depending on its
intensity), as well as disrupting litter/detrital (dead
organic matter) pools.
Fires initiate succession by reducing the number
of plants on a site and creating openings in the
canopy and near the ground, allowing understory
plant species and tree seedlings to grow. For
example, in the longleaf pine ecosystem in the
southern U.S., frequent low intensity fires keep the
ground clear of underbrush. These fires kill many
saplings of trees and a few larger trees, while
allowing sufficient seedlings to become established
and maintaining an open tree stand of low density. In
the absence of fire, the forest eventually loses the
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 4
Figure 3.
Suppression of natural cycles of fire disturbancein the Yellowstone National Park caused fires of
destructive dimensions in 1988. Photo by Jeff Henry
Figure 4.1 Photo by Jeff Henry
Figure 4.2 Photo by Jeff Henry
Figure 4.3 Photo by Jeff Henry
Figure 4.
Fires play an important role in forest renewaland succession. Figures 4.1, 4.2, and 4.3 sequentially
show the regrowth of vegetation following the 1988
Yellowstone National Park catastrophic fires.
longleaf pine and is completely dominated by older
shade-tolerant trees.
Fires revitalize the soil by allowing some
nutrients that are bound in the leaf and branch litter
to be returned to the soil. Trees and branches that fall
in forest fires create habitat for ground-nesting birds,
reptiles and amphibians
(Figure 5). Thus, fires canprovide conditions for a wide variety of plant and
animal species, and maintain biodiversity in forests.
Disturbances, such as fire, are therefore a major
diversifying force in forest ecosystems.
Figure 5.1 Photo by Larry Korhnak
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 5
Figure 5.2 Photo by Larry Korhnak
Figure 5.
Fires (5.1) release nutrients that were bound inthe leaves, branches and organic matter and make them
available for plant uptake (5.2). Burned logs and snags
are also habitats for a variety of mammals, reptiles and
amphibians.
However, it is important to note that not all
disturbances renew and invigorate ecosystems. Some
disturbances are damaging and result in
destabilization of the ecosystem. One example of
such a disturbance is chronic pollution, which may
cause long-term cumulative impacts that may not be
easy or possible to reverse.
Disturbances and Biodiversity
Prairies, oak savannas, and long-leaf pine
ecosystems of the Southern U.S. are examples of
ecosystems that are dependent on frequent,
low-intensity ground fires. These fires have occurred
historically at intervals of 1 to 25 years. The life
histories of the dominant species in these
communities have been shaped evolutionarily by fire
(Platt et al. 1988). Without fire, these ecosystems
gradually change to other vegetation types
(Figure6)
. A knowledge of natural disturbance regimes isessential for maintaining regional biodiversity.
Ecologists have evidence that species diversity
will be highest at some intermediate frequency or
intensity of disturbance (Connell 1978, Pickett and
White 1985). Frequent disturbance allows only
species that colonize rapidly to persist, whereas long
periods without disturbance may exclude desirable
dominant plant species from the ecosystem
(Figure7)
.Land managers should realize that species in any
region have adapted, through evolution, to a
particular disturbance regime. If we radically alter
that regime, many species will be unable to cope with
the change and will be eliminated.
Figure 6.1
Figure 6.2
How often do disturbances occur?
The disturbance regime is a combination of how
often the forest is disturbed (
frequency), how severethe disturbance is (
intensity), and how large theaffected area is (
extent). In general, the frequencyand intensity of natural disturbances are inversely
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 6
Figure 6.3
Figure 6.
Longleaf pine ecosystems are dependent onfrequent, low intensity ground fires. Fires maintain an open
canopy (6.1) and an extremely diverse flora in the ground
layer (6.2). In the absence of fires, other species, such as
vines and shrubs, are favored resulting in the loss of this
ecosystem's natural diversity (6.3).
Figure 7.
The intermediate disturbance hypothesisindicates that species diversity is highest at intermediate
frequencies or intensities of disturbance.
related. For example, volcanic eruptions or large
meteor impacts (high intensity) fortunately only
occur rarely (at a low frequency).
Some anthropogenic disturbances, such as
global climate change, occur only at a very low
intensity. However, these disturbances may be
directional and may cause large cumulative effects
over a long period of time. Because short-term
effects are small, they are very difficult to detect.
If a disturbance is very intense, ecosystems can
be totally destroyed, as when a forest is converted to
a parking lot. The more intense the disturbance, the
more difficult and costly it is to restore what was
there before. Severe erosion, for instance, may lead
to a degraded ecosystem that will never fully recover
to the prior condition without extremely costly
intervention, such as importing soil.
In urban areas the challenge is to determine the
appropriate natural disturbance regime to mimic
and/or reinstate.
Succession
What is succession?
The changes in an ecosystem that follow a
disturbance are collectively called
succession.Succession is a dynamic and continuous process,
often occurring gradually over time. Forest
succession is the change in species composition, age
and size, and ecosystem structure and function over
time.
Let's consider the development of an abandoned
farm field in the Piedmont of the Southeastern U.S.
over time to demonstrate succession
(Figure 8). Thisfarm field is surrounded by pine-hardwood forests,
typical of this part of the country
(8.1). During thefirst year or two, annual forbs cover the field
(8.2).Plants such as goldenrod and asters follow the
second and third year (Perry 1994). In this early
stage of succession, if we walk in this field, we can
hear birds such as grasshopper sparrows and
meadowlarks (Meyers and Ewel, 1990).
Figure 8.1
The grass-forb stage would be gradually
replaced by a shrub-pine-seedling community that
will last perhaps 15 to 20 years (without further
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 7
Figure 8.2 Photo by Natural Area Teaching Laboratory at
University of Florida
Figure 8.3 Photo by Natural Area Teaching Laboratory at
University of Florida
Figure 8.4 Photo by USDA Forest Service
Figure 8.
Sequence of successional stages in anabandoned farm field in the southeastern U.S. over time.
During the first years (8.1) the area is colonized by a
mixture of pioneer species (8.2). This stage is gradually
replaced by a shrub-pine community (8.3). In about
150-200 years, without further disturbances, an
oak-hickory forest may replace the pine forest (8.4).
disturbances)
(8.3). Birds such as the yellowthroatand field sparrow will be common. Pine seedlings
continue to grow in the abundant sunlight and, from
about year 25 to year 100, a pine forest may dominate
the site, providing habitat for birds such as the pine
warbler (Meyers and Ewel 1990).
Pine seedlings do not grow in the shade of taller
pines, but shade-tolerant oaks and hickories do. In
about 150 to 200 years, in the absence of fire, an
oak-hickory forest may replace the pine stand
(8.4).Birds such as the red-eyed vireo will thrive in the
deciduous forest (Meyers and Ewel 1990). The
seedlings of oak and hickory, capable of growing in
the shade of the older trees, will thrive and thus
replace the older oaks and hickories that die of
disease, old age or other causes.
However, if fire does occur again, or the trees
are harvested, pine forests can be maintained in the
landscape for hundred of years. Natural disturbances
can keep an ecosystem in a certain successional stage
for long periods of time. This issue will be discussed
further in the section
The Role of Disturbances inSuccession
.Why is succession important?
Urban trees are often managed as individuals
instead of as parts of ecosystems. Individual urban
trees and other vegetation may well provide many
benefits such as energy conservation, beauty,
recreation and climate amelioration. Yet, by
managing them as part of an ecosystem, additional
benefits can be achieved, such as increased animal
biodiversity, reduced storm-water runoff and erosion,
and significantly reduced maintenance costs.
Ecosystems that proceed through natural
succession may be managed with much less costly
intervention (
Figure 9). Urbanization and itsassociated activities have a profound impact on
natural succession, with the end result that little
natural succession occurs in most metropolitan areas.
For example, a widespread practice in urban forests
is to clean out the understory by raking leaves,
branches, seeds and seedlings on the forest floor.
Logs and snags are also often removed. Such a loss
of the understory, along with logs and snags may
have negative consequences for many wildlife
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 8
species dependent on these forest structures. In the
long term, such practices will lead to loss and
degradation of the forest itself, since nutrients are not
efficiently stored and recycled. As trees die, there are
no replacements, since the seed bank and seedlings
were removed, and natural succession is severed. As
a consequence, erosion increases and fertilizers and
soil amendments must be used to bring nutrients back
to the system.
Figure 9.1
Figure 9.2 Photo by Larry Korhnak
Figure 9.3 Photo by Larry Korhnak
Figure 9.
Ecosystems that are able to follow naturalsuccession, such as naturally landscaped backyards (9.1),
may be managed without costly intervention. Such
backyards will require less mowing, irrigation, fertilizers,
herbicides and pesticides (9.2) when compared to
backyards that use lawns extensively with only a few
scattered trees (9.3).
Likewise, the extensive use of ornamental
invasive species and "weed-free" lawn areas have
similar impacts. Herbicides, fertilizers, pesticides,
irrigation, and frequent mowing and raking are often
required to maintain such areas, representing extra
maintenance costs for urban managers. On the other
hand, natural ecosystems that are able to follow
succession can be managed without these additional
costs (
Figure 10).To successfully manage urban forest
ecosystems, managers need to understand how living
and dead vegetation, wildlife and various
disturbances interact. The ecological and economic
advantages of maintaining and/or restoring natural
succession need to be identified and incorporated into
the management of the urban forest ecosystem.
Types of succession
There are two types of succession, primary and
secondary.
Primary succession
Primary succession occurs in environments that
lack organic matter and which have not yet been
altered in any way by living organisms. Primary
succession includes the development over time of
the original substrate into a soil, and occurs over
centuries or even eons.
The 1981 eruption of Mount Saint Helens in
Washington provided an example of primary
succession
(Figure 11). This eruption wiped outmost or all traces of life in a substantial area to the
northeastern part of the mountain, leaving barren
areas of deep ash deposits
(11.1). A set of organismsadapted to survive and reproduce in these conditions
has since become established
(11.2). Some plantswere able to extract nitrogen directly from the
atmosphere (nitrogen-fixing species) and most were
also dependent on the formation of fungal association
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 9
Figure 10.1 Photo by Linda Robinson Figure 10.2
Figure 10.
Extensive use of ornamental invasive specieswill affect succession. This English ivy (10.1), for example,
displaced and killed a native pine species. Control of
invasive species, whether mechanical or chemical, is a
costly and time consuming operation (10.2).
with the roots (mycorrhizae) for extracting nutrients
from the ash (Perry 1994).
Figure 11.1 Photo by Michael P. Doukas
Because of these characteristics, such organisms
began to modify the site by accumulating nutrients
and building up soil organic matter. As these
organisms modify the site further, they will
eventually be replaced by other organisms better
adapted to the new conditions. For example, plants
that required abundant light to grow will be replaced
by more shade tolerant species.
As trees become established, there may be
relatively long periods of this successional stage
(e.g., Douglas-fir forests), which may persist only
until the next eruption
(11.3). In areas protected fromfuture eruptions, a relatively persistent ecosystem
may eventually occupy the site (e.g., Western
hemlock forest) (Perry 1994)
(11.4).Another example of primary succession occurs
on rock or subsoil surfaces exposed by landslides.
Primary succession can occur in urban forests where,
for example, surface soil and organic matter have
been completely removed from a site. In this case,
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 10
Figure 11.2 Photo by Lyn Topinka
Figure 11.3 Photo courtesy of R. Emetaz, U.S.
Department of Agriculture
Figure 11.4 Photo courtesy National Park Service
Figure 11.
The eruption of Mt. Saint Helens is an exampleof primary succession. It eliminated most traces of life in a
substantial area of the northeastern part of the mountain
(11.1). Less than a decade later, pioneer and early
successional plants have colonized the area (11.2).
Eventually, Douglas-fir forests will become established
(11.3) and, without further disturbance, over several
hundred years a Western hemlock forest may eventually
occupy the area (11.4).
primary succession can be hastened through the
addition of top soil.
Secondary succession
Secondary succession occurs in an environment
that has supported mature vegetation in the past, and
where, after the disturbance, the substrate (i.e., soil)
remains relatively intact.
Secondary succession also occurs in urban areas.
Suppose you decide to give up the fight with weeds
in your backyard and no longer mow your lawn. The
changes that take place will be typical of "old-field"
secondary succession. First, your backyard would be
colonized by a variety of plants, mostly annuals.
Within a few years, these plants would be joined by
perennials and smaller shrubs and the grass would
start to disappear. Later, a mix of taller shrubs and
tree species would seed in. Then, maybe 50 years
from now, you would have a successional forest in
your backyard.
Additional examples of secondary succession
include the changes in vegetation and ecosystem
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 11
characteristics in abandoned agricultural fields and
in forests after clear-cuts, windstorms or fires.
The Role of Disturbances in
Succession
Let's consider again the previous succession
example of an abandoned farm field in the
Southeastern U.S.
(Figure 8). Natural disturbancesmay occur
at any time during the development of theabandoned farm field into the pine or oak-hickory
forest. Natural disturbances can keep an ecosystem
in a certain successional stage for long periods of
time. Fire of any type, for example, may prevent
hardwood regeneration and maintain pine forests in
the landscape for hundred of years.
Natural disturbances vary in spatial scale (they
may occur in small, medium or large areas) and
temporal scale (they occur at different time periods).
For instance, individual trees or a group of trees may
die and fall, forming small gaps in the forest, while
wildfires may kill trees over thousands of acres
(Figure 12)
. Consequently, in many forestedecosystems, disturbance leads to a condition where
local successional patches are continuously formed,
leading to a "shifting mosaic" across the landscape
(Bormann and Likens 1979).
Figure 12.
In many forested ecosystems, disturbancessuch as fires, promote areas with burned and unburned
vegetation. Small successional patches are formed.
Eventually, across broad stretches of forest, there will be
patches of vegetation in several successional stages. Paul
Schmalzer
Different wildlife species are adapted to
different successional stages
(Figure 13). In"old-field" succession, for instance, pine warblers
would be common to the pine forest successional
stage, while red-eyed vireos and wood thrushes
would be found in oak-hickory forests.
Some mature forests (such as old-growth forests
in the northwestern US) take many hundreds of years
to reach a late successional stage. Some species
associated with these forests, such as the northern
spotted owl (
Strix occidentalis), may not survive ifonly earlier stages of succession are present (Eckert
1974). It is a major challenge is to determine and
maintain an appropriate mix of successional stages
within a landscape.
Figure 13.
These bird species require differentsuccessional stages as habitats. Adapted from Smith 1990
Different Stages of Succession Provide
Habitat for Different Wildlife Species
The American kestrel (
Falco sparverius) needsseveral stages of succession to meet its requirements
for food and cover
(Figure 14). This bird feedsprimarily on insects and small mammals, which are
present in early successional stages that contain
annual and perennial forbs and grasses. However, it
also requires intermediate and late stages of
succession, such as mixed woodlands (shrubs and
trees) and more mature forests, for nesting (Neilson
and Benson 1991).
American kestrels are widely distributed in
North America. However, the number of
southeastern American kestrels (
Falco sparveriuspaulus
) has decreased over 80% in the last 50 years(Wood et al. 1990). The main cause for the decline
has been the destruction of longleaf pine ecosystems,
the preferred nesting habitat for this species.
Other animals are also highly dependent on a
certain stage of successional development. For
instance, the structure and stage of development of
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 12
Figure 14.
American kestrels are widely distributed inNorth America. They feed on insects and small mammals,
which are present in early stages of succession (grasses
and forbs). However, the American kestrel also requires
intermediate and late stages of succession, such as mixed
woodlands (shrubs and trees) for nesting. Photo by David
Sarkosi
scrub vegetation has a profound effect on wildlife
habitat availability in Florida
(Figure 15).Figure 15.1 Photo by Wayne Peterson
Figure 15.2 Photo by Anne Birch
Figure 15.3 Photo by Paul Schmalzer
Figure 15.
The Florida scrub jay (15.1) is endemic to thescrub ecosystem in the southeastern U.S. It requires a low
shrub layer, bare ground and a few scattered trees (15.2)
avoiding canopied areas. The scrub ecosystem is
maintained by periodic fires (15.3).
The Florida scrub jay (
Aphelocoma coerulescenscoerulescens
) (15.1), an endemic species in CentralFlorida, is restricted to the pine/oak scrub
ecosystems
(15.2). This bird requires a low shrublayer, bare ground and a few scattered trees, avoiding
heavily canopied areas. The scrub ecosystem is
maintained by periodic fires
(15.3). In this case, iffire is excluded for long periods of time, a sand pine
canopy develops and scrub jays abandon the site
(Woolfenden and Fitzpatrick 1984)
(15.4).Succession in More Detail
Following a severe disturbance, sites are initially
dominated by early successional plants, called
pioneer species
. Pioneers are usually prolific seeders(or sprouters), fast-growing and short-lived species,
and generally intolerant of shade.
Pioneer species are then followed by shrubs and
early successional trees which, in turn, are eventually
replaced by late-successional species. Later
successional species are generally shade tolerant and
may grow much more slowly. Their seedlings will
survive and grow beneath an established canopy, and
eventually they will overtop the shrubs and replace
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 13
early successional trees (
Figure 16). Therefore,during succession, pioneers create conditions
conducive to species that will form an intermediate
or transitional community. This, in turn, creates
conditions favorable to species that form
late-successional communities.
Figure 16.
Following a disturbance, sites are initiallydominated by early successional plants, called pioneer
species (grasses and herbs). Pioneers are then followed
by other shrubs and early successional trees which, in
turn, are eventually replaced by late-successional species.
The composition and relative dominance of
various plant species changes over time because, in
part, they have different life strategies (some plants
grow best in full sun while others require shade, for
example). Succession can be viewed as a biological
race to make optimum use of available site
resources, such as light, soil, nutrients and water.
The pattern of vegetation found in a landscape
results from the interactions among soil types, water
availability, life history strategies of plants and
natural disturbances, all of which vary at different
spatial and temporal scales (Turner 1987). These
interactions will result, over time, in patches of
vegetation in different stages of succession across
the landscape. Therefore, the dynamics of forests
cannot be grasped by looking at only a single site, and
individual forests' stands should not be managed in
isolation from others in the landscape in which they
are embedded (Perry 1994).
Phases of secondary succession
Although succession is a continuous process, it
is useful to identify four main phases in secondary
succession (after Bormann and Likens 1979):
Figure 17.
Bormann and Likens (1979) proposed fourphases of secondary succession: reorganization,
aggradation, transition and steady state (or climax).
1. Reorganization phase
This is the period immediately following a
disturbance, when pioneer species are establishing.
There is usually a high availability of resources
(light, nutrients and water) and plant competition is
low. Because the quantity of leaves per unit of
ground area is not yet high, loss of water from leaves
is low and runoff of water is high. Consequently,
there is also a high potential for nutrient losses from
the soil and erosion, since nutrient uptake by plants is
low and water runoff high.
2. Aggradation phase
During this phase, plants rapidly accumulate
biomass, especially in woody stems, while detritus
also builds up on the ground. Restoration ecologists
usually try to shorten the reorganization phase, and
consequently hasten the aggradation phase, by
planting trees and shrubs that will grow quickly,
covering the site with leaf surface area.
3. Transition phase
This phase is characterized by a first wave of
tree mortality, caused by increased competition
among the pioneer trees, accumulation of snags and
logs, and the establishment of shade tolerant species
in the understory.
4. Steady State (or Climax) phase
The transition phase ends at a stage characterized
by large accumulations of both living biomass and
coarse woody debris (snags and logs). Forests that
reach this phase usually have high structural
diversity. Tree growth slows down in this phase,
accompanied by increased tree mortality; any growth
that does occur is offset by mortality.
The period of time that different ecosystems stay
in each of these successional phases depends on
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 14
environmental conditions and the nature of
disturbance regimes. For example, the reorganization
phase usually passes quickly but after severe
disturbances or in harsh climates it can be greatly
prolonged. Likewise, the aggradation phase varies
widely from one forest type to another, and is much
more rapid in favorable environments and where
denser, more even-aged stands develop.
Changes in ecosystem function, structure
and composition through succession
In addition to species composition, the structure
and functioning of ecosystems also change during
succession (
Table 2). For example, most forestecosystems only have abundant logs and snags
(structure) later during succession or after a
disturbance, such as a severe windstorm. In other
ecosystems, a low intensity, frequent disturbance
such as ground fire, burns low vegetation and some
trees, releasing nutrients and competition, which
changes both the pattern of nutrient cycling
(function) and the vertical layering of vegetation
(structure).
Table 2.
Changes in ecosystem function, structure andcomposition that occur during succession.
ECOSYSTEM
ATTRIBUTE
ASSOCIATED CHANGES
Function
high rainfall interception,
efficient nutrient cycling, cooler
environment
(evapotranspiration cooling),
high filtration of air pollutants,
lower runoff.
Composition
number of plant, wildlife andmicroorganism species.
Structure
presence of logs and snags,layering of live vegetation, litter
accumulation.
Species composition, ecosystem structure and
ecosystem function all change during succession and
are linked. By changing one component, such as
composition, there will be changes in the
ecosystem's function and structure. Invasive plants,
for example, can modify the functioning of
ecosystems (such as nutrient cycling and
productivity) as well as their species composition
(
Figure 18).For example,
Myrica faya has invaded youngvolcanic areas in Hawaii. These areas are extremely
nitrogen-deficient, and no native nitrogen-fixing
plants exist. Because
Myrica faya actively fixesnitrogen, it can form dense stands which
out-compete and may replace native vegetation. Its
invasion completely alters nutrient cycling and the
rate and direction of primary succession (Vitousek
1986).
Figure 18.1 Photo by Edward Gilman
Figure 18.2 Photo by Edward Gilman
Figure 18.
Several invasive plants, when introduced tonatural areas can modify the ecosystem's function and
alter natural succession. For instance, Chinese tallowtree
(
Sapium sebiferum) (18.1 tree, 18.2 inflorescence), canalter nutrient cycling and productivity by displacing native
vegetation in natural areas.
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 15
Changing Natural Succession: The
Casuarina Example
Casuarina
species are nitrogen-fixing,fast-growing species which are tolerant of infertile
soils. As a result, they would seem to be an excellent
choice for restoration projects, growing very fast,
shortening the reorganization and aggradation phases
and, consequently, reducing water runoff and
nutrient losses.
However,
Casuarinas are also highly aggressiveinvasive species
(Figure 19). By planting them,nitrogen is added to soils, altering the nutrient cycle.
A thick litter layer is also produced, reducing
germination of native plant species (Ewel 1986), and
altering the composition of plant species in the next
successional stage. Wildlife species are also affected,
since food sources and cover have been modified
(see also Chapter 9 - Invasive Plants)
.Figure 19.1
Figure 19.2
Figure 19.
Australian pine (Casuarina spp.), anaggressive invasive species, alters composition, structure
and function of ecosystems. These fast-growing species
form monospecific stands (19.1) that displace native
vegetation. They are seen here growing above the original
ecosystem's canopy (19.2).
Managing Disturbances and
Succession
Natural disturbance regimes and succession
have often been altered by humans, such as through
the introduction of exotic species and the
suppression of natural fires. To restore ecosystems it
is necessary to actively manage succession.
Goals for restoring ecological succession could
be economic (e.g., reducing maintenance costs of an
urban park), ecological (e.g., restoring the normal
hydrological period of an urban wetland) or aesthetic
or recreational (e.g., bringing birds and watchable
wildlife back to a neighborhood greenspace). These
goals are not mutually exclusive. For example, the
Patuxent Wildlife Research Center, near Laurel,
Maryland integrates both ecological and economic
goals in the management of succession. In 1960, the
U.S. Fish and Wildlife Service and Potomac Electric
Power Company agreed to implement a management
program that would develop a shrubland community
on a newly constructed right-of-way. Mowing was
halted and selective herbicides were periodically
applied to undesirable tree species. After 30 years,
the right-of-way was dominated by a shrub
community with high diversity and heavy use by
wildlife (Obrecht et al. 1991). Additionally, the
economic goal of reducing the number of trees
growing too close to powerlines has also been
achieved.
A restored site (an urban park, for instance) may
contain one or more types of ecosystems or remnants
of ecosystem. It is important then, to understand
historical patterns of succession in these ecosystems.
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 16
Information should be regularly collected to
document patterns and effects of management,
including current and historical site conditions, such
as soils, vegetation and disturbances. A site
inventory should be conducted to determine the
potential of the site (see also
Chapter 7 - Soil andSite Factors
). If a location is too degraded (due topollution, nutrient loading, or heavy pesticide use), it
may not be possible to restore it to a desired
historical successional stage. Realistic and feasible
restoration goals will ultimately determine a project's
success.
A particular stage, or a mosaic of different
successional stages, may be chosen as the objective
of restoration, based on the information collected
from the site inventory. The plant species to be
established should be those characteristic of the
corresponding natural successional stages. For
instance, planting trees and shrubs to attract as many
bird species as possible, many of which are not
typical of the desired successional stage, may not
lead to a sustainable objective.
Incorporating disturbances and succession
into small scale projects
Restoration projects in small areas may include
ecosystem(s) in which succession can be effectively
managed. These situations may include the
restoration of a bare site, elimination of invasive
species or re-introduction of more natural
disturbances.
Restoring bare sites
On a bare site, one stage of succession could be
chosen and a first effort to restore it could be by
planting a mix of all species typical of that
successional stage. However, it may take decades for
the trees to become mature, and litterfall and logs
may need to be imported if a late successional stage
is to be approximated. Introduction of natural
disturbance regimes, such as frequent ground fire,
may be desirable or necessary in some cases.
The Greening the Great River Park Program,
established in 1995, seeks to restore native
ecosystems along the Mississippi River in St. Paul,
MN. The project involves the landscaping of
industrial lands with four native plant ecosystems,
including forests and prairies. For example, a 35-acre
project will restore a natural prairie ecosystem close
to downtown St. Paul
(Figure 20). Prairies will bemaintained in a grassy successional stage by using
frequent low intensity fires. "Prescribed fire" and/or
shrub/tree cutting will be used to maintain this
grass-like stage and keep weeds under control. Such
strategy will provide, in the long run, an important
successional stage that was missing from this
urbanized landscape.
Figure 20.1 Photo courtesy of Chicago Wilderness
Eliminating invasive species
In some sites, removal of invasive plants may be
sufficient to release native species from competition
and restore natural succession. In the Ivy Removal
Project in Forest Park, Portland, removal of English
ivy (
Hedera helix) has renewed the health of theexisting vegetation
(Figure 21). English ivy is anaggressive exotic vine, extensively planted in the
surrounding neighborhoods, that has invaded the
park and suppressed its native vegetation. Regular
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 17
Figure 20.2 Photo courtesy of Greening the Great River
Park
Figure 20.
Prairies are maintained in a grassysuccessional stage by frequent low intensity fires (20.1).
The Greening the Great River Park initiative (20.2), uses
prescribed fire and/or cutting to maintain the grass
successional stage of prairies in a 35-acre project in
downtown St. Paul, MN.
removal of ivy has allowed native plant species to
follow natural succession by eliminating plant
competition.
Figure 21.
The Ivy Removal Project, removes English ivy(
Hedera helix) that has invaded Forest Park in Portland,OR, suppressing its native vegetation. In this case,
removal is sufficient to release native species from
competition and bring back natural succession.
However, in cases where the site has been
invaded by aggressive invasives and native
vegetation has been seriously damaged, removal of
invasives may have to be followed by planting. A
mix of native plant species typical of the desired
successional stage can be planted (as in the bare site
situation). An example occurred at Bill Baggs, a
heavily used urban park in Miami FL, where a
hurricane destroyed the monoculture of Australian
pines (
Casuarina equisitifolia) that previouslydominated the park's vegetation
(Figure 22).Figure 22.1
Figure 22.2
Figure 22.
Australian pine (Casuarina equisitifolia), ahighly invasive species, covered major areas of this urban
park, Bill Baggs (22.1, beyond buildings) and suppressed
native vegetation. After hurricane Andrew struck (22.2)
natural removal of Australian pines allowed managers to
restore the park's natural ecosystems.
Australian pines covered major areas of the park
and suppressed the native vegetation prior to the
hurricane. The "clean slate" that resulted from this
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 18
natural removal of Australian pines allowed
managers to reestablish the ecosystems that existed
before by planting native species typical of that area.
For more information on invasive species see
Chapter 9 - Invasive Plants
.Re-introducing natural disturbances
When re-introducing disturbances, ecosystem
characteristics and site conditions should be carefully
considered. In the Southern U.S., for example,
upland ecosystems are adapted to frequent (every 1
to 15 years) low intensity fires. In the case where fire
has been absent for long periods of time, thinning of
trees and/or manual removal of excessive fuel loads
may be necessary prior to application of prescribed
fire. Such management practice would prevent
damage (and other associated risks) by a high
intensity fire to which this ecosystem is not
adapted.
On the other hand, where high intensity
disturbances have been excluded for excessively
long periods, other strategies may need to be
pursued. For instance, the sand pine scrub
ecosystems, also in the Southern U.S., are adapted to
infrequent (every 15 to 100 years) high intensity
fires. Historically, after a lengthy fire-free period, an
intense fire occurs. If fires become too frequent, sand
pines disappear, and the association becomes oak
shrub or changes to other pines. If fires become too
infrequent, a xeric hardwood forest develops. Most
scrubs naturally depend on fires, but these fires need
to be applied in such a way that various stages of
development are maintained within isolated
fragments. Without these fragments, species with
special habitat requirements (such as the endemic
Florida mouse,
Podomys floridanus, the Floridascrub lizard,
Scelopors woodi, the gopher tortoise(
Gopherus polyphemus) and the sand skunk, Neosepsreynoldsi
) might be eliminated (Figure 23).Although preliminary steps have been taken to
develop techniques to burn the scrub, reintroduction
of fires in scrub ecosystems within urban areas may
not be feasible (due to liability, fire control
considerations and public reaction). In such areas,
patches of the scrub ecosystem could be maintained
by cutting, scraping and chopping to simulate fires
(Meyers and Ewel, 1990). Implementation of either
burning or mechanical techniques will require careful
attention to public education.
Figure 23.1 Photo by Anne Birch
Figure 23.2 Photo by Dave Rich
Figure 23.
In the scrub ecosystem of the southern U.S.,the correct frequency and intensity of fire is critical. If fires
become infrequent and too intense, a sand pine
ecosystem develops, excluding the endangered scrub
lizard (
Sceloporus woodi) (23.1) and gopher tortoise(
Gopherus polyphemus) (23.2).In other ecosystems, small or large gaps may
need to be cut to stimulate further succession. Such a
practice is becoming common for restoration of
longleaf pine ecosystems in the Southeastern U.S.,
where dense hardwood thickets now dominate many
sites. Gaps are cut and regenerated (
Figure 24), andprescribed fire is used to keep hardwoods from
re-invading.
Re-instating several different stages of
succession in one area can only be achieved on very
large land areas. Small sites may prove not to be
functional, although a small mosaic of semi-natural
successional stages may, nevertheless, be effective in
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 19
Figure 24.1
Figure 24.2
Figure 24.
In the longleaf pine ecosystems in thesoutheastern U.S., gaps are cut to stimulate succession
(24.1). Such practice allows regeneration (24.2) and the
return of a missing stage of succession to the landscape.
schoolyards for educational purposes. The
Schoolyard Ecosystems for Northeast Florida
initiative, for example, teaches students about
different animals that utilize a combination of small
patches of mowed areas, early succession and more
mature areas (
Figure 25). Some important structuralelements, such as logs, snags, brush piles and plants
with different heights, are constructed to simulate a
more mature area and to promote wildlife.
Figure 25.1
Figure 25.2
Figure 25.
The Schoolyard Ecosystems for the NortheastFlorida initiative (25.1) encourages the establishment of
successional stages in school areas. The objective is to
teach students about different animals that utilize a mowed
area, an early successional patch and a more mature area
(25.2).
Incorporating disturbances and succession
into large scale projects
Parts of larger project areas (greater than about
20 acres) may present situations similar to small
scale projects (with some bare sites, sites invaded by
exotic invasive species and sites where disturbances
could be re-introduced). But in larger areas, there is
also the opportunity to manage for several stages of
succession at the same time, if a mixed successional
landscape is typical of the ecosystem in question or
could be used for educational purposes. Learning
about the ecosystem, its stages of succession and
how they fit into the overall landscape becomes
critically important. The Chicago region, for
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 20
example, contains prairies, savannas, woodlands and
forests. The absence of fire has impacted these
ecosystems and their stages of succession in the
landscape. Oak savannas have been almost totally
excluded in the Chicago area and prairies have been
invaded by woody species. Historically, the
frequency and intensity of fire determined the
successional stage of these ecosystems, that is,
whether a given piece of land would be an open
grove or a dense forest (
Figure 26). Restorationefforts in this case are based on re-introducing fires.
To date, fire has been reintroduced in several areas
and native species typical of the region's ecosystems
are being planted. In some areas, native trees have
been cut to allow more light to reach the ground
(
Figure 27). Such practices allow the landscape tosupport several stages of succession, ranging from
open prairies to forests.
Figure 26.
Historically, the frequency and intensity of firedetermined the successional stage of ecosystems
(whether a given piece of land would be an open grove or
a dense forest) in the Chicago area. Photo courtesy of
Chicago Wilderness
Figure 27.1 Photo courtesy of Chicago Wilderness
Figure 27.2 Photo courtesy of Chicago Wilderness
Figure 27.
Due to suppression of fires, the once opensavannas in the Chicago area (27.1) developed into
thickets of vegetation deprived of sunlight (27.2). Oak
savannas began losing their vast diversity of plants and
animals and were almost excluded from the landscape.
Some continuous or intermittent form of
management may be needed to create disturbances in
situations where human activity has severely
modified natural disturbances cycles. Efforts to
restore historical flooding cycles in the South Platte
River watershed illustrate the need for an integrated
restoration plan for a whole region. The floodplains
along the South Platte river in Nebraska consist of a
mosaic of different vegetation types. The presence of
wooded or open vegetation was historically
determined by natural periodic floods. Forests were
confined to drier sites, since native woody species,
such as willows (
Salix spp.) and cottonwoods(
Populus spp.), would not survive flooding. Grasses,on the other hand, could tolerate flooding, allowing
for open areas along the river.
Channelization and upstream development
reduced the water flow and, consequently altered
flooding periods. As a result, previously open areas
of the floodplain are nowdrier and invaded with
adjacent native forest species. Before channelization
and development, migratory birds, such as the
endangered whooping crane (
Grus americana) andthe sandhill crane (
Grus canadensis) (Figure 28),used the open grassy floodplains for feeding and
avoided roosting in areas with abundant woody
species. Because of these changes in natural
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 21
succession, the whooping crane population decreased
80% over 30 years.
Figure 28.
Sandhill crane (Grus canadensis) populationshave decreased as a consequence of successional
changes in ecosystems along the South Platte River.
Photo by Larry Korhnak
Current restoration efforts include selective
clearing of trees along some parts of the river.
However, restoration of historical patterns of
succession in the region will ultimately depend on
the reinstatement of normal flood periods. An
integrated upstream restoration effort along all the
South Platte River extension will be required to
achieve such a goal (U.S. Fish and Wildlife Service
1981).
In another example from Central Florida, scrub
vegetation without fire grows very tall and thick with
very little open space for the endangered gopher
tortoise (
Gopherus polyphemus) to nest and feed(
Figure 29). Little sunlight can reach the ground andherbs, which are a food source for this tortoise, can
no longer grow (Smith 1997). Conservationists are
using prescribed fires to restore the open nature of
the historic scrub ecosystem. A number of other
animals with wide ranges, such as black bear,
white-tailed deer, bobcat, gray fox and spotted skunk,
also utilize the scrub and should benefit from the
efforts as well (Meyers and Ewel 1990).
Figure 29.
Without fire the scrub ecosystem grows verytall and thick with very little open space for the endangered
gopher tortoise (
Gopherus polyphemus) to nest and feed.Photo by Ben Coffin (with the Friends of the Enchanted
Forest in Titusville, FL)
Conclusions
Disturbances and succession occur virtually in
every place on earth. To successfully manage the
urban forest ecosystem, managers need to understand
natural disturbance regimes and how species
composition, ecosystem structure and wildlife
interact over time within these regimes.
There are many opportunities to incorporate the
concepts of disturbance and succession in either
small or large scale urban restoration projects:
• Learn about the historical disturbance regimes
that occur in the ecosystems in your region.
Remember that disturbances have a variable
spatial and temporal scale. If appropriate,
propose re-introducing some disturbances back
to these ecosystems.
• Understand the successional stages of the
ecosystem(s) you are managing.
• Take advantage of any research conducted that
relates to historical site conditions, including
soils, climate, vegetation and disturbances.
Conduct a site analysis and decide whether your
restoration plans should include disturbances and
succession management.
• Manage site-specifically but remember that the
site you are managing belongs to a larger
landscape that may contain other successional
stages.
• Remember that species composition,
ecosystem structure and ecosystem function are
linked and change during succession. Invasive
plants, for example, can modify the functioning
and structure of ecosystems as well as their
species composition.
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 22
• Start with small demonstration projects.
Remember that succession and natural
disturbances do not always follow our human-made
geographical boundaries. Integrated efforts may be
needed to better achieve restoration goals at the
landscape level.
It is also important to involve the local
community in every step of the restoration process.
Successful urban forest restoration projects often
include an educational and outreach component.
Educate people about the benefits of succession and
the benefits of re-introducing natural disturbances.
Suggested Readings
Adams, L. and L.E. Dove. 1989.
Wildlifereserves and corridors in the urban environment: A
guide to ecological landscape planning and resource
conservation
. Columbia, MD: National Institute forUrban Wildlife.
Adams, L. W. 1994.
Urban wildlife habitats: Alandscape perspective
. Minneapolis, MN: Universityof Minnesota Press.
Franklin, J.F. 1993. Preserving biodiversity:
Species, ecosystems or landscapes?
EcologicalApplications
3(2): 202-205.Smith, D.S. and P.C. Hellmund. 1993.
Ecologyof greenways: Design and function of linear
conservation areas
. Minneapolis, MN: University ofMinnesota.
Cited Literature
Bormann, F.H. and G.E. Likens. 1979.
Patternand process in a forested ecosystem
. New York, NY:Springer-Verlag.
Connell, J.H. 1978. Diversity in tropical rain
forests and coral reefs.
Science 199: 1302-1310.Eckert, A.W. 1974.
The owls of North America.New York: Doubleday and Co.
Ewel, J.J. 1986. Invasibility: Lessons from
South Florida. In
Ecology of biological invasions ofNorth America and Hawaii
, edited by H.A. Mooneyand J.A. Drake. Berlin, Germany: Springer-Verlag.
Meyers, L. and J.J. Ewel. 1990.
Ecosystems ofFlorida
. Gainesville, FL: University of CentralFlorida Press.
Neilson, E.L. Jr. and D.E. Benson. 1991.
Wildlife Habitat Evaluation Handbook
. ColoradoState University: Department of Fishery and Wildlife
Biology.
Obrecht, H.H.III, W.J. Fleming and J.H.
Parsons. 1991. Management of powerline
rights-of-way for botanical and wildlife value in
metropolitan areas. In
Wildlife conservation inmetropolitan environments
, edited by L.W. Adamsand D.L. Leedy. Columbia, MD: National Institute
for Urban Wildlife.
Perry, D.A. 1994.
Forest ecosystems. London:The Johns Hopkins University Press.
Pickett, S.T.A. and P.S. White. 1985.
Theecology of natural disturbance and patch dynamics
.New York, NY: Academic Press, Inc.
Platt, W J., G.W. Adams and S.L. Rathbun.
1988. The population dynamics of a long-lived
conifer (
Pinus palustris). American Naturalist131:491-525.
Smith, R.B. 1997. Gopher tortoises (
Gopherpolyphemus
). Kennedy Space Center and EnchantedForest Nature Sanctuary, October 16 1997 [cited
1997]. Available from
http://www.nbbd.com/godo/ef/gtortoise/index.html
Turner, M.G. 1987.
Landscape heterogeneityand disturbances
. New York: Springer-Verlag.U.S. Fish and Wildlife Service. 1981. The Platte
River ecology study special research report. U.S.
Fish and Wildlife Service, Jamestown, ND.
Jamestown, ND: Northern Prairie Wildlife Research
Center Home Page [cited July 16 1997]. available
from
http://www.npwrc.usgs.gov/resource/othrdata/
platteco/platteco.htm
Vitousek, P.M. 1986. Biological invasions and
ecosystem properties: Can species make a
difference? In
Ecology of biological invasions ofNorth America and Hawaii
, edited by H.A. Mooneyand J.A. Drake. Berlin, Germany: Springer-Verlag.
Chapter 4: Plant Succession and Disturbances in the Urban Forest Ecosystem 23
Wood, P.B., J. Schaefer and M.L. Hoffman.
1990.
Helping our smallest falcon: The SoutheasternAmerican kestrel
SS-WIS-16. Gainesville, FL:Florida Cooperative Extension Service, University of
Florida.
Woolfenden, G.E. and J.W. Fitzpatrick. 1984.
The Florida scrub jay: Demography of a
cooperative-breeding bird.
Monogr. Populat. Biol.no. 20. Princeton, New Jersey: Princeton University
Press.
Chapter 5: Developing a Restoration Plan That Works1
William G. Hubbard
21. This is Chapter 5 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. William G. Hubbard, Southern Regional Extension Forester, Cooperative Extension Service, The University of Georgia, Forest Resources Bldg. 4-402,
Athens, GA 30602-4356.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
A plan can be defined as a predetermined course
of action. Regardless of the type of plan, they all
have a number of similar components. First a vision
- a future desired condition or state - must be defined.
Goals and objectives are then used to achieve the
vision. Measurable goals and objectives form a basis
for project evaluation. Guiding principles are
incorporated into the goals and objectives to ensure
that achievement of the vision is attained in a high
quality and defendable manner. It is important to
identify and involve stakeholders in the planning
process from the beginning and to have a framework
and a process to identify and resolve issues.
Gathering and analyzing information about the
restoration site is critical. An action plan with a
timeline outlines activities and responsibilities. A
plan for monitoring should be developed before the
project is started. Monitoring evaluates how well the
project objectives have been met. Determining
project costs, benefits and funding sources is
essential to the restoration project's success. As the
plan progresses, care should be taken to outline its
relationship to other plans. A well-thought-out,
well-developed plan will help the community
achieve its vision.
Introduction
According to many planners, a plan can be
defined as a predetermined course of action. Plans
have three characteristics:
they must involve thefuture
, they must involve action and they must involvean element of personal or organizational
identification or causation
. In other words, plans aredesigned to get someone or something (a business
for example) from point A to point B in a certain
time frame. This will most likely be accomplished
by someone or a group of people taking actions
toward the stated goal(s) and objective(s)
(Figure 1).Figure 1.
Plans provide a common vision and a pathtoward its accomplishments. Photo by Larry Korhnak
Chapter 5: Developing a Restoration Plan That Works 2
But why develop a plan? We have heard all the
lines before and if we are not careful we will fall into
the same cynical trap of thinking about why we don't
like to plan and why plans don't work. For example,
plans:
• sit on the shelves and collect dust!;
• rarely succinctly develop the goals, objectives
and pathways to success;
• are shaped by politics or personnel changes
which often render them useless;
• often become outdated as soon as they are
done; and
• don't fit today's style of managing by the seat
of our pants!
However, what can a plan provide?
• a common vision for the community;
• well-defined and measurable goals and
objectives;
• a logical plan of action;
• organized and focused efforts toward
accomplishing a goal;
• a document to assess and justify budgetary
requirements; and
• a plan to obtain funding.
Principles of Planning
Larsen et al. 1990, reviewed many plans and
provided a number of suggestions for principles of
good planning. His tips are to:
1. Integrate and balance resource allocations.
Good planning integrates all urban resources. It
does not pit one resource against another.
2. Communicate a clear vision. Good planning
generates a clear vision of the outcomes and
contributions to meeting local, regional, and
national needs.
3. Recognize limits. Good planning recognizes
limits on the outcome's ability to produce a mix
of goods and services in perpetuity.
4. Seek informed consent. Good planning
welcomes citizen involvement. Decisions
should be made and explained openly. Dialogue
among disparate interests should be facilitated.
5. Finish in a reasonable time. Good planning is
completed in a reasonably short period of time.
Short periods facilitate incremental planning and
stability among key players. People can actually
harvest the fruits of their labor.
6. Be people-oriented. Good planning recognizes
that individuals, both inside and outside the
agency or effort, make the difference between
good and bad plans
(Figure 2).7. Promote active administrative leadership. Good
planning requires active involvement and
leadership on the part of responsible
administrators.
8. Match analysis to questions at hand. Good
planning involves use of analytical tools for
purposes of evaluating options. Such tools
should not drive or dominate the process.
9. Be both locally oriented and nationally
balanced. Good planning should be locally
oriented and should also give ample
consideration to national constituencies.
Types of Plans
Before we begin the nuts and bolts of urban
forest ecosystem restoration planning let's review
some of the more common types of plans:
Strategic Plan
Strategic planning can be defined as a
disciplined effort to produce fundamental decisions
and actions that guide an organization. This kind of
planning typically involves broad-scale information
gathering, an exploration of far-reaching alternatives,
an emphasis on future implications of present
decisions and an ability to accommodate divergent
interests and values (Bryson, 1988).
Chapter 5: Developing a Restoration Plan That Works 3
Figure 2.
Good planning recognizes that individuals, bothinside and outside the agency or effort, make the
difference between good and bad plans. Photo by Larry
Korhnak
Comprehensive Plan
Comprehensive planning involves taking into
account as many planning needs as possible under
one umbrella plan. The comprehensive plan often
involves stakeholder input early on. Many counties
and cities now undergo comprehensive planning
which includes plans for economic development,
land-use plans and environmental plans.
Master Plan
Similar to the comprehensive plan, the master
plan is not as comprehensive and involves more
specific goals and objectives. Master Street Tree
Plans of the past for example involved planting
plans, maintenance plans, budgetary plans and
educational plans.
Operational Plan
The operational plan can be defined as that
which puts the strategic, comprehensive or master
plan into action. It outlines who is responsible for
what by when. Activities are often outlined on a
timeline with expected outcomes.
Management Plan
Similar to the operational plan but more
detailed, the management plan might even outline
day-to-day management activities that need to be
accomplished in order to achieve the stated goals and
objectives.
Restoration Plan
As we willl see later, a restoration plan is merely
a type of management, master or action plan that
focuses on restoring specific areas.
Budget or Fiscal Plan
The budgetary or fiscal process of any
organization or entity is usually complex. Monetary
management is complex because it equates very
closely to people's value systems. Budgetary
instructions, accounting procedures, etc., are all
enclosed in this important type of plan.
Communication and Education Plan
A final plan worth mentioning is the
communication and education plan. In a sense, this
is a strategic plan where appropriate communication
of goals, objectives, issues and progress is vitally
important to the success of any plan. Special care
must be given to produce a good communication
plan.
Etc. Etc. Etc. Plan
Plans are made for everything these days.
Land-use plans, zoning plans, etc. The importance is
not necessarily the specific name of the plan but what
it purports to achieve. It is also interesting to point
out that plans are often nested and involve a systems
approach
(Figure 3).Components of the Restoration
Plan
Regardless of the type of plan, they all have a
number of similar components. In the following
sections we will discuss several of these components.
We will also discuss some of the issues involved in
creating a successful plan. Specifically, the
following outline will be followed for developing a
restoration plan:
• Scope, Vision, Goals and Objectives
• Guiding Principles
Chapter 5: Developing a Restoration Plan That Works 4
Figure 3.
An example of a systematic approach toplanning involving many different plans.
• Stakeholder Involvement
• Identifying Problems and Issues
• Information Gathering and Analysis
• Developing a Timeline and Detailing Actions -
the Action Plan
• Monitoring and Evaluating
• Budget and Finance
• Relationship to Other Plans
Scope, Vision, Goals and Objectives
Scope
Before we look at vision, goals and objectives it
is important to understand the scope of the proposed
restoration project. This will have an important
influence on the development of the plan. Many
times, this is the difference between a restoration
project versus a restoration program or one project
versus many projects. For example, community or
ecosystem-wide plans are different from a plan
specifically designed for a section or plot of land in
an urban area. Regardless of the size or scope,
planning techniques are very similar. The
complexity and interrelationships distinguish the
two. Scope is important to keep in mind when
initiating the planning process.
Vision
Plans are based on vision. Vision involves
creativity, imagination, and sometimes thinking
outside of the box. Basically, the vision is the
desired future condition or state (
Figure 4). It is theresult of closing your eyes and literally visioning
what the outcome of your plan might look like. A
shared vision is critical if you want everyone's
buy-in (see below for stakeholder input).
Figure 4.
A vision is the desired future condition or state.Greening the Great River Park in St. Paul, MN has a plan
for restoring industrial lands along the Mississippi River.
Their vision is to have these restored industrial areas look
like they were set in an established forest. Photos by Rob
Buffler
An excellent example is from Metro, the
regional government in Portland, Oregon. They are
working on what is called the Metropolitan
Greenspaces Vision:
•
It is our vision to protect, on a long-term basis,natural areas, open spaces, trails and greenways
that lend character and diversity to our region
even as more and more people move here to
share our special place.
Chapter 5: Developing a Restoration Plan That Works 5
•
It is our vision to balance our urban focus anddrive for economic health and prosperity with an
array of wildlife habitats in the midst of a
flourishing cosmopolitan region.
•
It is our vision to conserve and enhance adiversity of habitats woven into a lush web of
protected greenspaces. (Metropolitan
Greenspaces Master Plan, July 1992).
Goals and Objectives
Goals and objectives are used to achieve your
vision. Measurable goals and objectives form a basis
for project evaluation
(Figure 5).Figure 5.
The Metropolitan Greenspaces Master Plan inPortland, Oregon has a goal to restore green and open
spaces in neighborhoods where natural areas are all but
eliminated. Whitaker Ponds is one of the selected
neighborhood restoration sites. Photo by courtesy of
Metro Regional Parks and Greenspaces
Goals and objetives are actual steps, which if
taken in an orderly, strategic fashion will result in
attainment of the vision. For example, the goals for
the Metropolitan Greenspaces System include:
•
Create a cooperative regional system of naturalareas, open space, trails and greenways for
wildlife and people in the four-county
metropolitan area.
•
Protect and manage significant natural areasthrough a partnership with governments,
nonprofit organizations, land trusts, interested
businesses and citizens, and Metro.
•
Preserve the diversity of plant and animal lifein the urban environment, using watersheds as
the basis for ecological planning.
•
Establish a system of trails, greenways andwildlife corridors that are interconnected.
•
Restore green and open spaces inneighborhoods where natural areas are all but
eliminated.
•
Coordinate management and operations atnatural area sites in the regional Greenspaces
system.
•
Encourage environmental awareness so thatcitizens will become active and involved
stewards of natural areas.
•
Educate citizens about the regional system ofgreenspaces through coordinated programs of
information, technical advice, interpretation and
assistance.
Another example of possible goals and
objectives comes from the Society for Ecological
Restoration (SER) and is based on a common
definition of ecological restoration. According to
SER, ecological restoration is the process of assisting
the recovery and management of ecological integrity.
Ecological integrity includes a critical range of
variability in biodiversity, ecological processes and
structures, regional and historical context, and
sustainable cultural practices.
The definition above was developed by the SER
Policy Working Group after almost a year of
consultation and deliberation; it was passed by a mail
vote of the SER Board in October 1996. The SER
Policy Working Group is now working on a detailed
description of attributes, goals and objectives, which
will accompany the definition:
•
To restore highly degraded but localized sites;•
To improve productive capability of degradedproduction lands;
•
To enhance conservation values in protectedlandscapes;
•
To enhance conservation values in productivelandscapes
(Journal of Restoration Ecology1995)
Chapter 5: Developing a Restoration Plan That Works 6
The Bill Baggs Cape Florida Restoration
Project Example
The Bill Baggs Cape Florida Restoration Project
(1992) can also be used to exemplify the
development of a vision, goals and objectives in a
restoration project. Bill Baggs is a heavily used
urban park near Miami. Prior to Hurricane Andrew's
strike in 1992, the park had extensive areas
dominated by Australian pine (
Casuarinaequisitifolia
), an invasive tree. The natural removalof Australian pines by the Hurricane provided a great
opportunity to restore the park to conditions closer to
its previous natural conditions. The Bill Baggs Cape
Florida Park vision, goals, and objectives were:
Vision
:• To reforest the park with native vegetation
(
Figure 6); and• To improve the historical, recreational and
educational opportunities and the facilities
in the park (
Figure 7).•
Goals:• The primary goal was to restore the park's
original natural processes while providing
compatible public recreational
opportunities;
• Reforest the park to predominantly native
vegetation for beneficial environment
purposes and for public outdoor recreation
benefits; and
• Eradicate exotic plants at Cape Florida and
re-establish the historic native natural
communities.
Objectives:
• Stabilize and protect the natural and
cultural resources of the park;
• Re-open public recreation areas as soon as
possible;
• Preserve and restore the original natural
communities and natural processes of the
park, to the extent possible; and
• Restore pre-hurricane levels of public
recreation.
Figure 6.
The Bill Baggs Cape Florida Restoration Planwas to reforest the park with native vegetation. Photo by
Mary Duryea
Figure 7.
The second vision of the Bill Baggs CapeFlorida Restoration Project was to "improve the historical,
recreational and educational opportunities and the
facilities in the park." Photo by Mary Duryea
Guiding Principles
Guiding principles are incorporated into goals
and objectives to ensure that the plans vision is
attained in a high quality and defendable manner
(Figure 8)
.Some guiding principles that have been used in
the past for example are:
Chapter 5: Developing a Restoration Plan That Works 7
Figure 8.
Guiding principles such as sound scientific factsare incorporated into goals and objectives to ensure that
the plan's vision is attained in a high quality and
defendable manner. Photo by Larry Korhnak
•
Science - Projects need to be planned andsupported by sound scientific facts and reasoning.
•
Stewardship - Ultimately, the goal of manyrestoration projects is stewardship. Agreement
on what this means will be important.
•
Integration and partnership - Today's worldnecessitates multi-discipline, agency/entity
involvement.
•
Economics - Sound economics insures the planmatches the economic resources.
Stakeholder Involvement
It is important to identify and involve
stakeholders in the restoration planning process from
the beginning. Stakeholders are the people who will
be impacted by the restoration project. Buy-in from
community, government, independent organizations
(NGOs, Universities), private sector, investors,
employees/employer, among others is absolutely
necessary at an early phase. Failure to do so will
undermine the process and the plan and may be a
waste of time and money
(Figure 9).Figure 9.
It is important to identify and involvestakeholders in the restoration planning process from the
beginning. Photo by Mary Duryea
What kind of input will be necessary? Some of
the important questions you may ask at the outset
are: Who are your stakeholders and what
information do you want from them? Are they
members of the community that may be affected by
the decisions made? Make an extensive list of who
may have an interest in your restoration project.
Retreat-style settings, Delphi surveys and other
ways to gather input and understand issues have been
used to include stakeholders. The Delphi process was
originally developed in the 1950s by Olaf Helder and
Norman Dalkey, both scientists at the Rand
Corporation, as an iterative, consensus building
process for forecasting futures. It has since been
deployed as a generic strategy for developing
consensus and making group decisions in a variety of
fields. An interest group is typically assembled,
either through correspondence or face-to-face
discussion, to assess issues of mutual concern.
While the individuals in the group share a
common interest (the subject of the Delphi), they
usually represent different points of view. Each
member of the group is asked to give his/her
comments regarding a particular set of issues. A
facilitator analyzes the individual comments and
produces a report documenting the response of the
group. The individuals then compare what each
person said to the group's normative response as a
basis for discussion. The discussion, again via
remote or face-to-face conversation, is used to share,
promote, and challenge the different points of view.
Once this is done, the participants, having the benefit
of the previous discussion, anonymously comment
on the issues again. A new group report is generated
and the process repeats itself. This process continues
until the group reaches consensus or stable
disagreement.
Chapter 5: Developing a Restoration Plan That Works 8
If you would like further information about
stakeholder involvement and identification, and the
Delphi process, check the
Suggested Readingssection at the end of this chapter.
Identifying Problems and Issues
When involving stakeholders it is important to
have a framework and a process to identify and
resolve issues
(Figure 10).Figure 10.1 Photo by Larry Korhnak
Figure 10.2 Photo by Larry Korhnak
Figure 10.
When involving stakeholders it is important tohave a framework and a process to identify and resolve
issues, such as issues concerning compatible recreational
uses.
Examples of identification include expert review
of your project from a university faculty member or
private consultant or public review through town hall
meetings or forums, the media, etc. The issues
confronting the project may be social, economic and
environmental. Addressing these issues will help to
revise and shape the restoration plan. Some example
issues may include:
• Compatible recreational uses;
• Biological and physical limitations for the site;
• Consensus on vision, goals and objectives;
• Private property rights issues;
• Land conflicts;
• Conflicts with current infrastructure;
• Conflicts with other plans; and
• Compatibility with laws and regulations.
Information Gathering and Analysis
Once your vision, goals/objectives, guiding
principles and stakeholder input have been
determined, a next logical step will be to determine
where to obtain the information you will need for the
restoration project
(Figure 11).Figure 11.
Information gathering and analysis such as thissite assessment of a wetland will guide the development
of goals and objectives. Photo by Larry Korhnak
The information gathering and analysis phase
might incorporate the use of the following tools:
Natural Resources
1. aerial photographs/remote sensing data
2. geographical information systems (GIS)
Chapter 5: Developing a Restoration Plan That Works 9
3. field data collection
4. soil maps
5. climatic data
Historical
1. library
2. historical societies
3. municipal records
Infrastructure
1. GIS
2. city and utility agencies
Community/Social
1. stakeholder input and others
2. town meetings and focus groups
Where can you go for this information? More
and more can be obtained from the Internet. GIS
maps and data, soils information, climatic data, etc.
are sometimes located on various websites. Other
information can be found at the public works or
other municipal departments. Social and stakeholder
data usually needs to be collected first hand as
discussed previously.
Following this very important step of data
collection and analysis it may be necessary to refine
or redirect the current vision, goals and objective.
For example, stakeholder input may be needed again
as you collectively review the results from GIS
maps. A real problem in some parts of the country
for example is the control and management of
invasive exotic species. The vision may have been
the complete eradication of all invasive species in a
given geographical location. Review of maps and
other data, however, may render achievement of this
vision extremely costly or impossible. A renewed
vision may be a healthy ecosystem with a
manageable level of this invasive species and
complete eradication of it on public lands.
Stakeholders will need to understand why the vision
has been revised. Maps are an excellent way to
communicate.
Developing a Timeline and Detailing
Actions - The Action Plan
Once agreement has been coalesced, the next
step is to outline the beginning of an action plan. In
general, there is more than one way to reach the plans
objectives. Successful restoration projects often
spend time early on identifying, evaluating and
selecting alternative paths and solutions. Various
criteria are used to reach consensus on the proper
alternatives to use. Economic analysis (cost-benefit,
capital budgeting, social accounting methods, etc.) is
one way. Public input and voting is another. It is
important to remember to use the guiding principles
to choose the best alternative.
An example of restoring a longleaf ecosystem in
an urban setting using three alternatives should
illustrate this. The restoration team and stakeholders
determined three potential courses of action after
extensive discussion involving restoring a 15-acre
tract of land in a metropolitan area.
•
Roller drum and chop site. Plant two-year-oldcontainerized longleaf pine seedlings, burn
regularly, keep nuisance wildlife out with
fencing. Monitor health and regeneration
success.
•
Leave existing vegetation on the site. Plantsix-year-old longleaf pine saplings. Apply
herbicides.
•
Seed the area after a light winter burn.Manually remove the weeds, brush and
competition.
Following the decision to follow one alternative,
the next step is detailing the actions. Basically,
action planning states what will be done, by whom,
and when. It includes a timeline and estimated costs
and resource needs
(Figure 12).One thing that is often overlooked is developing
a system for foreseeing and overcoming barriers in
action planning. The best systems involve enhanced
communication plans with the general public,
stakeholders, consultants and others involved in
developing and implementing the plan.
Chapter 5: Developing a Restoration Plan That Works 10
Figure 12.
An example action plan timeline.Monitoring and Evaluating
The next step is monitoring and evaluating the
plan's effectiveness. How do you do this? Some
examples relating to the regeneration restoration
project cited before include:
Site visits
1.
regeneration surveys2.
hydrologic and soils testing3.
testing and evaluating the ecosystemstructure and functioning
Physical mapping
1.
aerial photography2.
GIS mappingSocial
1.
public reaction2.
benefits and effects on neighborsIt is important to have a plan for monitoring
before the project is begun
(Figure 13). Monitoringmay begin with base-line data collection and
continues on during project implementation.
Monitoring evaluates how well the project's
objectives have been met. It demonstrates and
elucidates both successes and failures.
Figure 13.
A plan for monitoring should be developedbefore the project is started. Monitoring evaluates how
well the project objectives have been met. Photo by Larry
Korhnak
Budget and Finance
Determining project costs, benefits and funding
sources is essential to the restoration project's
success
(Figure 14). Following are a few questionsthat the planning/implementation team, along with
stakeholders, policy makers and others need to
address.
Figure 14.
Determining project costs, benefits and fundingsources is essential to the restoration projects success.
Photo by Larry Korhnak
Chapter 5: Developing a Restoration Plan That Works 11
What will this project cost? What are the
benefits?
•
Benefit-Cost Ratio: In this type of analysis, theproject is undertaken when the benefit to cost
ratio is greater than one. If more than one
project is desired, then the project with the
highest ratio is undertaken.
•
Net Present Benefits (NPB): Due to the natureof many public projects, it may take many years
to reap the full benefits. To take into account
the long-term nature of these projects, all costs
and benefits are equated to a common time
(usually the present). If there is anything left
after subtracting net present costs from net
present benefits, the project will be of value to
the community and can be judged as
economically sound, all else being accounted for.
•
Capital Budgeting: In many instances, a capitalbudgeting process will need to be invoked.
Ranking of competitive projects by benefit-cost
ratio or net present benefits may help in the final
analysis. Great care should be taken to outline
the assumptions used and to equate all projects
as to scale and time.
•
Use of other economic tools: Be sure to reviewthe literature for more information that may be
useful, specifically opportunity cost and the
traditional economic tools that have been
modified for the new fields of ecological and
environmental economics.
What are the Funding Mechanisms?
Some funding options to investigate include:
• special options tax
• bond issuance
• general tax revenues
• private foundations
• public and private grants
Robert Miller's Urban Forestry textbook (Miller
1997) lists a number of funding mechanisms that can
be investigated. Finally, many successful plans have
been implemented because they were already
developed and the right funding came through. The
importance of having a plan ready when budget
opportunities become available cannot be stressed
enough. Timing and preparedness go hand-in-hand.
For references and additional information on budget
and finance issues check the
Suggested Readingssession at the end of this chapter.
Relationship to Other Plans: Plans are
Interrelated
As the planning process proceeds, it will
become obvious that no longer can we plan in a
vacuum. The interrelationship and interdependence
of planning is more relevant today than ever before.
In addition, many citizens are beginning to realize
that a healthy economy is tied directly to a healthy
ecosystem, making environmental planning very
important. More communities are incorporating a
systems approach to planning that is similar to
comprehensive planning
(Figure 15).Figure 15.
As the plan progresses, care should be takento outline its relationship to other plans. Photo by courtesy
of Metro Regional Parks and Greenspaces
As your plan progresses, care should be taken to
outline its relationship to other plans. These plans
include:
• Comprehensive
• Transportation
• Land
Chapter 5: Developing a Restoration Plan That Works 12
• Capital improvement
• Risk management and hazard assessment
• Community facilities and utilities plan
• Public outreach
1. media
2. schools
3. professional groups
• Volunteer action plan
Conclusion
Urban ecosystem restoration planning is a
highly complex and dynamic process. As with any
process, there are innumerable factors to consider
and no cookbook solutions. A careful review of the
literature and of other plans from around the country
should be beneficial to anyone considering
restoration plan development. A well-thought-out,
well-developed restoration plan will help the
community achieve its vision
(Figure 16).Figure 16.
A well-thought-out, well-developed restorationplan will help the community achieve its vision. Photo by
Larry Korhnak
Suggested Readings
Woodley S., J. Kay and G. Francis. 1993.
Ecological Integrity and the Management of
Ecosystems. St. Lucie Press. 220 p.
Miller, R. 1997. Urban Forestry: Planning and
Managing Urban Greenspaces. Upper Saddle River,
New Jersey: Prentice Hall. 502p.
For more information about the Delphi process:
Adler, M. and E. Ziglio (eds.) Gazing Into the
Oracle: The Delphi Method and Its Application to
Social Policy and Public Health. London: Kingsley
Publishers (in press).
Delbecq, A.L., A.H. VandeVen and D.H.
Gustafson. 1975. Group Techniques for Program
Planning: A Guide to Nominal Group and Delphi
Processes. Scott & Co.
Linstone, H. and M. Turoff. 1975. The Delphi
Method: Techniques and Applications. Addison
Turoff, M. 1970. The Policy Delphi.
J .ofTechnol. Forecast. and Soc. Change
, 2(2):Turoff, M. 1972. Delphi Conferencing:
Computer Based Conferencing with Anonymity.
J.of Technol. Forecast. and Soc. Change
, 3(2): 159Turoff, M. 1974. Computerized Conferencing
and Real Time Delphis: Unique Communication
Forms. Proceed. 2
nd International Conference onComputer Communications, 135
For more information about stakeholders:
The World Bank Participation Sourcebook
(Chapter III: Practice Pointers in Participatory
Planning and Decisionmaking) (on line at:
www.worldbank.org/wbi/sourcebook/sb03.htm).
Fischman, R. L. and M. S. Squillace. 2000.
Environmental Decisionmaking. Anderson
Publishing Co. third edition.
Chopra, K., G.K. Kadekodi and M.N. Murti.
1989. Participatory Development: People and
Common Property Resources. New Delhi: Sage.
For more information about budgeting and
finance:
Agarwal, A. and S. Narain. 1989. Towards
Green Villages: A Strategy for Environmentally
Sound and Participatory Rural Development. New
Delhi: Centre for Science and Environment.
Brown, G. and C.B. McGuire. 1967. A Socially
Optimal Pricing Policy for a Public Water Agency.
Water Resources Research.
Chapter 5: Developing a Restoration Plan That Works 13
Clark, C.W. 1976. Mathematical
Bioeconomics: The Optimal Management of
Renewable Resources. New York: John Wiley.
Costanza, R. ed. 1991. Ecological Economics:
The Science and Management of Sustainability New
York: Columbia University Press.
Dasgupta, P., S. Marglin and A. Sen. 1972.
Guidelines for Project Evaluation. New York:
United Nations.
Dixon, J.A. and M.M. Hufschmidt eds. 1986.
Economic Valuation Techniques for the
Environment. Baltimore: Johns Hopkins University
Press.
Tietenberg, T. 1988. Environmental and
Natural Resource Economics, 2nd ed. Glenview, Ill.:
Scott, Forsman.
Cited Literature
Bryson, J. M. 1988. Strategic Planning for
Public and Nonprofit Organizations. San Francisco,
California: Jossey-Bass Publishers.
Larsen, G., A. Holden and D. Kapaldo. 1990.
Synthesis of Critiques of Land Management
Planning. USDA-Forest Service, Washington:
FS-452. Policy Analysis Staff.
Miller, R. 1997. Urban Forestry: Planning and
Managing Urban Greenspaces. Upper Saddle River,
New Jersey: Prentice Hall. 502p.
Metropolitan Greenspaces Master Plan. 1992.
A Cooperative Regional System of Natural Areas,
Open Space, Trails and Greenways for Wildlife and
People.
Chapter 6: Restoring the Hydrological Cycle in the
Urban Forest Ecosystem1
Lawrence V. Korhnak
21. This is Chapter 6 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kämpf Binelli, and L.V. Korhnak, Eds.) produced
by the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Lawrence V. Korhnak, Senior Biological Scientist, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University
of Florida, PO Box 110410, Gainesville, FL 32611
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Forests provide a protective cover for the
landscape and cycle much of the precipitation back to
the atmosphere. They are essential components of
many aquatic ecosystems. When native forests are
removed and replaced with impervious surfaces and
high maintenance vegetation, much of the water that
would have been returned to the atmosphere or
percolated into the ground water, washes off the
landscape. The quantity and energy of this runoff
erodes landscapes, deteriorates aquatic habitat, and
floods human habitat. In addition, the runoff washes
away chemicals that have been concentrated on the
land to support high maintenance vegetation.
Polluted runoff, referred to as non-point source
pollution, is our nation's most serious water quality
problem. Reestablishing the urban forest can help to
protect the landscape and associated aquatic
ecosystems. Runoff can be reduced, use of polluting
chemicals can be lowered, and aquatic habitat and
ecosystem links can be reestablished.
Forest Water Cycle
Forest Water Cycle Overview
On average, two-thirds of precipitation entering
U.S. forests is returned to the atmosphere through
evaporative processes. Most of the remainder
percolates through the porous forest soils to streams
or fills underground geological storage space. Forests
function as a protective layer and are a key link
between the atmosphere and the land in the water
cycle (
Figure 1).The forest canopy intercepts both the falling rain
and its kinetic energy. Some of the intercepted
rainfall is evaporated to the atmosphere while the
rest drips to the ground as through-fall or runs down
the trunk as stem-flow. Forest soils are generally
very porous so little through-fall washes over the soil
surface as runoff to water bodies. Instead, most of
the through-fall seeps or infiltrates into the soil. The
sun's energy evaporates water from inside the leaves
in the canopy in a process called transpiration.
Transpiration from the foliage creates a moisture
deficit that is transmitted as a suction force all the
way down to the tree roots. Much of the soil water is
sucked up by plant roots to replace the water
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 2
Figure 1.
Forests are a key link in the cycle of waterbetween the atmosphere and the land.
transpired from the foliage. Depending on the soils,
geology, and other factors, some of the remaining
soil water will percolate deeper, and some will move
laterally into nearby streams.
Interception and Through-fall
Much of the rain falling on a forest landscape
will first impact the canopy vegetation (
Figure 2).Some will eventually drip to the ground and some
will be evaporated from the vegetation back to the
atmosphere. This evaporative loss is referred to as
interception loss. The percentage of rainfall
intercepted and evaporated by the forest canopy in
the U.S. ranges from about 12%-48% of rainfall
depending on the climate, tree type, and canopy
structure. For example, interception losses of 12%
were reported for mature hardwoods in the southern
Appalachian mountains (Kimmins, 1997), 18% for
pine flatwoods in Florida (Riekerk et al. 1995), 40%
for ponderosa pine in Arizona, and 43% for a
beachforest in New York (Kimmins 1997).
Figure 2.
Much of the rain falling onto a forest landscapewill first impact the canopy vegetation. Some will
eventually drip to the ground, but on an annual average
12% to 48% will be evaporated from the vegetation back
to the atmosphere.
The kinetic energy of rainfall can cause
significant soil erosion (
Figure 3). A one inch stormwill deliver about 2 million foot pounds per acre of
kinetic energy. Most of this energy can be adsorbed
by the forest canopy and forest litter. Without this
shield the rainfall energy will break up soil particles
into smaller more easily transportable materials.
Most of the splashed soil will move downhill. The
fine particles resulting from the rainfall breakup of
larger soil aggregates will clog soil drainage and
result in more runoff. This can result in sheet flow
and sheet erosion. This water energy will concentrate
in small depressions called rills, which over time may
develop into gullies. Left unchecked, erosion can
carve canyons (
Figure 4).One way researchers measure interception losses
is to measure rainfall inputs into the forest (either
above the canopy or in a nearby open area), and at
the same time measure through-fall with collection
devices (for example troughs and funnels) under the
canopy (
Figure 5). Interception losses are thedifference between these two measurements.
Interception is related to canopy leaf area which can
be measured with leaf fall traps.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 3
Figure 3.
The kinetic energy of rainfall can causesignificant soil erosion. A one inch storm will deliver about
2 million foot pounds per acre of kinetic energy. Much of
this energy can be adsorbed by the forest canopy. Photo
by Andrew Davidhazy, Rochester Institute of Technology,
School of Photographic Art and Sciences.
Figure 4.
In Georgia at Providence Canyon State Parkyou can observe the severe erosion that can result from
permanently removing the forest canopy from the
landscape.
Figure 5.
Through-fall is measured with troughs andfunnels placed under the canopy. The measurements are
often correlated with canopy leaf area, which is estimated
in this figure with leaf fall traps.
Transpiration
Transpiration is the evaporation of water from
within living plant tissue. Solar energy creates a
water potential gradient by evaporating water
through leaf openings called stomata (
Figure 6).This gradient is transmitted to the roots where soil
water is absorbed and transported to the foliage via
the conductive network of xylem. Transpiration in
the continental US ranges from about 30%-60% of
precipitation and is a function of climate, vegetation
type, and stand structure (leaf area). A Florida pine
forest transpires almost a million gallons per acre in a
year (Riekerk et al.1995).
Figure 6.
Energy from the sun evaporates water frominside living plant tissue through openings called stomata.
The guard cells can open and close the opening and
provide some regulation of the process. Photo micrograph
courtesy of the Center for Microscopy and Micro Analysis.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 4
The "Transpiration Pump" also helps to draw
nutrients from the soil into the tree. Trees have been
described as "solar powered chemical machines that
mine the soil for minerals" (
Figure 7). In addition tosucking up water, trees also draw in their required
nutrients. For vigorously growing forests, trees will
uptake about 100 kg/ha/yr of Nitrogen and 15
kg/ha/yr of Phosphorus (Kimmins 1997).
Figure 7.
With the aid of the "transpiration pump" treescan remove significant amounts of nutrients from the soil.
Transpiration is difficult to measure, but two
methods are the sap flow gage and the leaf chamber.
Sap flow is measured by applying a known heat
source around the trunk of the tree and measuring the
heat energy that is removed by the sap flowing up the
trunk to replace transpired water (
Figure 8).Figure 8.
A sap flow gage measures sap flowing up thetree trunk on its way to be transpired from the leaves.
The leaf chamber is a small transparent chamber
that encloses the leaf and measures the moisture that
enters and exits the chamber
(Figure 9). The positivedifference is transpired moisture. One major
difficulty of both these methods is scaling up the
measurements from individual trees and leaves to the
forest.
Figure 9.
The leaf chamber measures water transpiredfrom foliage enclosed in the chamber. Scaling these
measurements up to the forest level is a challenge.
Evapotranspiration
The sun's energy will evaporate water from
many of the components of the forest ecosystem.
Often researchers will combine all the evaporative
losses into one measurement, called
Evapotranspiration (ET). Evapotranspiration
includes transpiration, interception evaporation, soil
evaporation, and water body surface evaporation
(
Figure 10). In temperate forest regions about 70%of the precipitation is returned to the atmosphere
through evapotranspiration (Hewlett 1982).
Infiltration
Infiltration is the movement of water from the
soil surface into the soil (percolation is the
movement of infiltrated water through the soil).
Generally, there is a lot of space between the soil
particles in forest soils and this allows water to easily
seep into the soil (
Figure 11).For coarse to medium textured forest soils, the
infiltration capacity is high and ranges from about 15
to 75 mm/hr (Brooks et al. 1991). Vegetation, both
in the canopy and on the forest floor, protect the soil
from compaction by rain energy. Forest floor
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 5
Figure 10.
Evaporation is a term used for the sum of allthe evaporative water losses in a forest.
Figure 11.
Water moves into the soil through both thesmall spaces between soil particles and the larger spaces
between blocks of soil.
vegetation, both alive and dead, prevents rain splash
erosion from clogging soil pores with colloidal
material (
Figure 12). In addition, forest floorvegetation increases infiltration capacity by retarding
surface flow, thus giving water more time to sink in.
Raking the forest floor clean of vegetation, as is done
in many urban parks, will reduce the ability of the
forest to soak in rainfall and thus increase storm
water runoff. Roots and old root channels also make
the soil more pervious.
Figure 12.
The live and dead vegetation on the forest floorserve important functions in the infiltration process. Photo
by Ken Clark.
Runoff
Surface runoff in the forest landscape occurs
when the rainfall (or through-fall) intensity exceeds
the infiltration capacity of the soil and surface
storage is full. Forest soils generally have infiltration
capacities that exceed most rainfall events. So how
does storm flow occur in the forest? Precipitation
falling on the stream channel and saturated areas near
the stream are the source of most early storm flow.
As rain continues to fall, the saturated source area
expands due to direct precipitation and infiltration,
and from water infiltrating elsewhere and moving
down slope. This expanding saturated variable
source area contributes most of the storm flow to
forest streams (
Figure 13).Figure 13.
An expanding saturated source areacontributes most of the storm flow to forest streams.
One method scientists use to answer questions
regarding the hydrological impacts of forest
management is with paired watershed experiments.
In this method the water outputs of similar drainage
basins are measured with hydrological structures like
flumes and weirs (
Figure 14). Data are collectedfrom the watersheds for several years before
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 6
treatment in order to establish statistical
relationships. Then the treatment is applied to one of
the watersheds and the post treatment data is
analyzed to determine if the statistical relationship
changed in a significant way.
Figure 14.
A weir is one type of structure used formeasuring forest stream flow. It is an important tool for
answering questions about the effects of land
management on the hydrological cycle. Photo by Hans
Riekerk.
Seepage and Groundwater
Much of the water infiltrating into the soil
supplies evapotranspiration demands. The remainder
will seep down (percolate) until it hits a permeability
barrier, for example clay or rock, and then will move
down laterally. Lateral seepage provides flow to
streams in dry weather (base flow). In more
permeable soils, seepage may move deeper down
into porous geological formations, called aquifers.
Depending on the geology, the groundwater may
remain stored in the aquifer for less than a week or
for over 10,000 years. In regions with dissolved
limestone geology (karst) groundwater will often
move down gradient in undergrounds rivers. When
these underground rivers intersect surface openings
they form springs. When they intersect openings in
the ocean floor they form blue holes. Occasionally
the pressure of the spring flow will force the water
above the ground surface to form fountain-like
artesian springs. Most of the earth's water is in the
oceans, but over 99% of the liquid water associated
with the land is groundwater. Groundwater is an
essential resource for drinking water (
Figure 15). Inmany areas of the country forest land is being bought
to protect ground water supplies from pollution
associated with other land uses. High quality
groundwater is also important for growing the food
we eat (
Figure 16).Figure 15.
In much of the U.S. groundwater suppliescritically needed drinking water. This photo shows
groundwater returning to the surface as a spring and
some of its surrounding forested catchment area. Springs
keep many rivers flowing during periods of dry weather.
Figure 16.
Good quality groundwater is also important forirrigating and growing the food we need to eat.
Impacts of Urbanization on the Water
Cycle
Overview
Forests provide a protective cover for the
landscape and cycle much of the precipitation back to
the atmosphere. They are also essential components
of many aquatic ecosystems. When native forests are
removed and replaced with impervious surfaces and
high maintenance vegetation, water that would have
been returned to the atmosphere or percolated into
the groundwater, washes off the landscape (
Figure17
).Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 7
Figure 17.
The urban landscape distorts and shortens thehydrological cycle.
The percent of runoff increases almost in direct
proportion to the impervious area. In addition,
impervious surfaces prevent storage of water in the
soil and urban activities often fill in natural water
storage areas like flood plains and wetlands. The
result is that increased amounts of water are
delivered to water bodies in a shorter period of time.
More water moving faster causes floods and erosion
that damage both life and habitat (
Figure 18).Figure 18.
The replacement of forest with urbanimpervious surface will degrade stream health. Source:
Schueler 1992.
Water washing over the urban landscape
transports nutrients and other chemicals into aquatic
ecosystems. This type of pollution is termed
"non-point source", and it is our nations most serious
water quality problem. Nutrients can stimulate algae
production to the point where the ecosystem is no
longer inhabitable by native organisms. Other
pollutants have toxic effects on aquatic organisms
and contaminate drinking water.
Forests are an integral component of many
aquatic ecosystems. They provide water temperature
moderation, support food webs, provide in-stream
habitat and stabilize stream banks. Breaking the
forest ecosystem-aquatic ecosystem link will
diminish the biological value of aquatic ecosystems.
Water Quantity Problems
Altering the Landscape Will Alter the
Hydrology
Disturbing a forested landscape with agricultural
and urban activities will alter the response of the
landscape to precipitation events. Forests retain and
evaporate most of the incoming precipitation
(
Figure 19). The hydrograph (graph of dischargeover time) for the forest watershed reflects this lower
and more gradual release of water (
Figure 20).Figure 19.
In the forest water cycle, most of theprecipitation is returned to the atmosphere and infiltrates
into the soil. Flow to streams is slowed and moderated by
the forest's complex structure.
In agricultural landscapes, heavy machines and
livestock compact the soil. Compacting squeezes the
soil particles closer together and reduces the soil pore
space. With less pore space, rainfall will not soak into
(infiltrate) the soil as well. A landscape with a
reduced infiltration capacity will produce more
runoff (
Figure 21). The hydrograph will have ahigher peak and because more water travels the faster
surface route, the peak flow rate will occur earlier.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 8
Figure 20.
Water from the forest is released in loweramounts and more slowly compared to other land uses.
Source: Beaulac and Reckhow 1982.
Figure 21.
In the agricultural landscape, soil compactionresults in less infiltration and increased runoff. Photo by
USDA.
In the urban landscape even more runoff will be
produced faster because the soil is often highly
compacted or covered with impervious surfaces
(
Figure 22). Impervious area distorts thehydrological cycle. Infiltration, storage, and
transpiration are reduced and runoff increases in
proportion to the percent impervious area (
Figure23
). Urban impervious surfaces are designed to movewater quickly off site. More runoff and less delay of
runoff results in higher peak-flows and flooding.
Figures 24, 25, and 26
show generalized changes inthe water cycle resulting from different levels of
impervious area in urban landscapes (EPA 1993a).
Figure 22.
In the urban landscape, impervious surfacesproduce more runoff in a shorter period of time.
Figure 23.
When forests are replaced with impervioussurfaces, transpiration and infiltration are reduced and
runoff increases in proportion to the percent impervious
area. Source: Novotny and Olem 1994.
Figure 24.
In low density residential areas with 10 to 20 %impervious area, evapotranspiration and groundwater
account for most of the water loss.
The Importance of Storage
In the forest water cycle, precipitation is
captured and stored by the forest vegetation, forest
litter, and soils. If preconditions are dry and the
amount of rainfall is moderate, much of this water
will be temporally stored and returned to the
atmosphere through evaporative processes. Under
wetter conditions there is less storage, and more
rainfall may become stream flow. However, the
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 9
Figure 25.
As the percent impervious area increases inhigher density residential area outputs to
evapotranspiration and groundwater are reduced and
surface water runoff increases.
Figure 26.
Surface water predominates the water cycle incommercial and industrial areas.
complex structure of the forest landscape creates a
tenuous path that delays the water's release from the
land. This delay will result in more gradual stream
inputs and a gentler rise in stream flow (
Figure 27).Figure 27.
Storage of precipitation, in the forest canopy,litter, soil, and wetlands, is important for reducing flood
hazards.
In urban systems, the storage capacity of
vegetation is reduced, soil compaction reduces soil
storage space and impervious surfaces prevent
rainfall from entering much of the soil altogether.
Often flood plains, wetlands and other depressional
storage sites are filled in, further reducing storage
(
Figure 28). As a result, more water reaches thestream in a shorter period of time.
Figure 28.
In urban areas flood plains and wetlands areoften filled in reducing hydrological storage. In addition,
these areas near the water are often prime real-estate.
These factors combine to set up conditions for destructive
flooding events.
Flooding and Aquatic Habitat Degradation
Flooding and erosion resulting from altered
landscapes are serious concerns for human life and
property. They also impact aquatic organisms and
degrade their habitat. Impervious surfaces often form
an effective conveyance system for rapid transport of
runoff into urban water bodies such as streams. The
quantity of stream flow is equal to the cross sectional
area of the stream channel multiplied by the average
stream velocity. To convey the additional runoff
produced from disturbed landscapes, the cross
sectional area of the stream and/or the stream
velocity must increase. Streams increase their cross
sectional area by rising up their banks, and many
have natural flood plains for conveying runoff from
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 10
extreme precipitation events. In the urban landscape,
the flood plain may be filled in and built in, and
flooding will occur (
Figure 29).Figure 29.
Reduced storage, high runoff rates, andconcentrated peak flows will often result in flooding in
urban landscapes.
The energy of water increases exponentially as
its velocity increases. High energy urban stormwater
runoff scours stream bottoms, and erodes and
undercuts their banks (
Figure 30). Stream sidevegetation and aquatic habitat are washed away and
conditions are set for destructive landslides.
Figure 30.
High energy urban stormwater runoff scoursstream bottoms, erodes and undercuts their banks. This
degrades aquatic habitat and creates dangerous landslide
conditions.
Water Quality Problems
Non-Point Source Pollution
Increased runoff is not the only concern when
the forested landscape is altered. Generally, forest
ecosystems require little if any extraneous inputs of
chemicals and disturbance is infrequent. On the other
hand, to sustain agricultural and urban activities,
nutrients, pesticides, herbicides, and energy
producing chemicals are concentrated on the
landscape. Urban impervious surfaces are associated
with intensive land uses that generate pollution. They
function as an efficient conveyance system for
transporting pollutants directly to aquatic
ecosystems, bypassing the pollutant removal
functions of the soil (
Figure 31).Figure 31.
Roads often function as an efficient system fortransporting pollutants to aquatic ecosystems.
Soil disturbance is frequent in agricultural and
urban watersheds. Construction in urban watersheds
removes the protective vegetative cover and erosion
can produce 10 to 100 times more sediment than
natural areas (up to 50,000 ton/km
2/yr) (Novotnyand Olem 1994) (
Figure 32).Figure 32.
Pollution washed from altered landscapes isreferred to as non-point source pollution. This aerial photo
shows a sediment plume in a lake washed from upstream
construction in an urban watershed. Photo by Hans
Riekerk.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 11
Stormwater generated from urbanized
landscapes will wash pollutants into aquatic
ecosystems, often causing severe dysfunction
(
Figure 33). This type of diffuse pollution is callednon-point source pollution. In contrast, point source
pollution originates from focused sources such as the
effluent from waste water treatment plants (
Figure34
).Figure 33.
Stormwater runoff will wash many pollutants offurban impervious surfaces into aquatic ecosystems.
Figure 34.
Point source pollution often originates fromwaste water treatment plants and factories whose
discharges are emitted at discrete, identifiable locations
such as pipes and ditches.
Much progress has been made in cleaning up
point source pollution, but treating non-point source
pollution problems are generally more difficult and
costly. Non-point source pollution is responsible for
the majority of the impaired use of our nations
waters. Of the total pollution load to our nations
waters, non-point sources contribute 90% of
nitrogen, 90% of the fecal coliform bacteria, 70% of
the oxygen demand, 70% of the oil, 70% of the zinc,
66% of the phosphorus, 57 % of the lead, and 50% of
the chromium (Thompson et al. 1989).
Measurement of Non-Point Source
Pollution
Different land uses have been measured to
export different amounts of substances (
Figure 35).Activities that increase runoff (such as soil
compaction and paving), and activities that expose
pollutants to washing off the land (such as over
fertilization), will contribute to higher export rates.
The exports are usually measured in kilograms
leaving the land area (per hectare) for a year. These
values are determined by measuring the quantity and
quality of water leaving a known area of drainage
basin.
Figure 35.
The forest landscape exports much lesspollutants than more intensive land uses.
Typically, the first step in measuring the
amount of water leaving a land area is to develop a
stream height-discharge relationship (rating
equation) for a stable section of the stream channel.
On smaller streams the stream cross section is often
modified into a more hydraulically uniform shape by
a flume (
Figure 36) or weir (Figure 37).Discharge is the product of cross sectional area
of the stream channel multiplied by the average
stream velocity. Depth measurements are taken along
the cross section to calculate the area and velocity
measurements are taken at different depths at
different locations to determine the average velocity.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 12
Figure 36.
Flumes are flow modification structuresdesigned to accurately measure the amount of water
passing through them. They are self cleaning and can
work with relatively low head loss, but they are very
expensive.
Figure 37.
Weirs also measure flow, and they are lessexpensive than flumes. However, they dam up the water
behind them which can cause many problems.
This process is repeated for a wide range of flow
conditions and the data are used to construct an
equation that will estimate stream flow from stream
height. These equations have been determined under
lab conditions for weirs and flumes, but real world
conditions will modify their flow characteristics, so
on-site calibration is good practice.
Flow proportional sampling is required for an
accurate determination of the amount of substance
(for example nitrogen or phosphorus) passing
through the measurement station. This is
accomplished by a microcomputer that reads the
stream stage, calculates a flow from the rating
equation, and activates an automated sampler to take
a water sample when the specified volume of water
has passed through the measurement section.
Here is a simple hypothetical export calculation.
From a topographic map and an inspection of the
watershed, the contributing area to a stream gaging
station was determined to be 10 ha. The total water
passing through the measurement channel for a year
was 10,000 m
3. The average total nitrogenconcentration of the volume weighted samples was
5,000 mg/m
3. The mass of nitrogen is calculated bymultiplying the flow volume by the concentration.
For this example:
10,000 m
3 x 5,000 mg/m3 = 50,000,000 mg or50 kg of nitrogen. Thus the land export was 50 kg/10
ha/yr or 5 kg/ha/yr.
From the perspective of the receiving water
body, for example an urban lake, the land export is
referred to as a load. The loading rates of the
nutrients nitrogen and phosphorus into water bodies
are one of the crucial factors that determine their
biological and physical conditions. Proposed changes
in land use in a lake's watershed can be used to
predict the change in nutrient loads and the probable
biological and physical impacts to the lake. Export
and load information are used to guide watershed
restoration efforts.
Eutrophication
Nutrient loading of aquatic ecosystems causes
eutrophication or nutrient enrichment. Symptoms of
eutrophication may include decreased water clarity,
algal blooms, nuisance growth of macrophytes,
unpleasant taste and order, dissolved oxygen
depletion, fish kills, and altered species diversity and
richness (
Figure 38) (National Academy of Sciences1969).
Nutrients in urban storm water runoff are the
leading source of impairment of our nation's
estuaries (EPA 1996). Developmental stresses pose a
serious threat to the health of these productive and
complex ecosystems (
Figure 39). By the year 2010almost half of the U.S. population will live near
coastal waters, and the population of many coastal
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 13
Figure 38.
Nutrients washed from high maintenance urbanlandscaping may stimulate algae growth and distort
system ecology. In severe cases the resulting
environmental changes will make the ecosystem
uninhabitable to native species.
cities is predicted to triple in the next 15 years (EPA
1996). Nutrients imported into estuarine watersheds
to sustain high maintenance landscapes are washing
into the estuaries and disrupting ecological
relationships. For example nitrogen from fertilizers
can stimulate dense growth of algae that will shade
out sea grass. Sea grass is critical spawning and
nursery habitat for much of our seafood (
Figure 40).Figure 39.
Increasing development in our coastal areaswill result in more storm water runoff making an already
serious problem worse.
Figure 40.
Fertilizers in storm water runoff can destroycritical habitat for many of the species that provide us
delicious seafood. Photo Philip by Greenspun, M.I.T.
Nutrients are essential for the existence of both
terrestrial and aquatic ecosystems but the level of
nutrients will play a major role in determining the
character of the ecosystem. When urban storm water
washes excess nutrients into an aquatic ecosystem,
the nature of the ecosystem will change. This human
influenced process of nutrient enrichment of aquatic
ecosystems is called cultural eutrophication. In
severe cases the resulting environmental changes
may make the ecosystem uninhabitable to native
species.
Most often the root of the problem is excessive
inputs of the critical plant nutrients, nitrogen and
phosphorus. When one or both of these nutrients
limit plant growth, additional inputs will stimulate
aquatic weed and algae growth. The aquatic plant
community often provides the primary source of
organic carbon energy and forms the foundation of
the ecosystem. Changes in this critical component of
the ecosystem will have system wide impacts.
Often the impacts are undesirable. Algal blooms
will decrease water clarity. This lowers the
recreational and aesthetic value of the water body. If
the water body is an important drinking water
supply, algal blooms may impart a bad taste and odor
to the water and clog treatment systems. In addition,
dense algal blooms will shade out submerged aquatic
plants. These aquatic plants are important breeding
and nursery grounds for many sport and food fish.
Conditions in highly nutrient rich water bodies favor
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 14
filter and bottom feeding fish. These will multiply to
the detriment of many other species and reduce the
species diversity of the ecosystem. Aquatic
ecosystems, especially shallow ones and those with
low flushing rates, tend to keep and recycle the
nutrients they obtain. Therefore, it is difficult and
expensive to restore many impacted water bodies.
Oxygen
Urban storm water can reduce dissolved oxygen
levels in aquatic ecosystems by reducing the
dissolved oxygen holding capacity, by stimulating
algae respiration with nutrients, and by stimulating
microbial respiration with organic carbon sources
(
Figure 41).Figure 41.
Urban storm water can reduce dissolvedoxygen levels in aquatic ecosystems by reducing the
dissolved oxygen holding capacity, by stimulating algae
respiration with nutrients, and by stimulating microbial
respiration with organic carbon sources.
The oxygen holding capacity of water is a
function of the water temperature. Specifically,
colder water can contain more oxygen than warmer
water. For example, water at 3 degrees C can contain
13 mg/l of dissolved oxygen while water at 35
degrees C will only hold 7 mg/l of dissolved oxygen.
In an urban system, water from heated buildings, hot
streets and roofs can raise the temperature of water
bodies. Removal of trees that shade urban streams
will also raise water temperatures. To compound the
problem, elevated water temperatures will often
increase the metabolic rate of cold blooded aquatic
organisms, thus increasing their need for oxygen.
Nutrients, especially phosphorus and nitrogen,
can stimulate increases in algae populations. When
there is adequate sunlight and inorganic carbon,
algae will produce large amounts of oxygen during
photosynthesis. In fact, oxygen levels may actually
climb above saturated levels in a system with high
densities of algae during bright sunlight. However, at
night or during extended cloudy periods, the algae
will remove large amounts of oxygen from the water
for their metabolic needs. Under extreme conditions,
the algae can deplete the dissolved oxygen supply
and fish kills will occur (
Figure 42). This is mostcommon under conditions where diffusion of oxygen
from the atmosphere into the water is impaired, such
as when the water is covered with ice or when the
water column is prevented from mixing due to
thermal stratification.
Figure 42.
Under certain conditions, high levels of algaecan deplete oxygen in water resulting in fish kills.
Algae and fish are not the only competitors for
dissolved oxygen in aquatic ecosystems. Aquatic
bacteria will feed on organic materials washed into
water bodies. They convert oxygen into carbon
dioxide in a biochemical process similar to our
metabolism of food. When large amounts of organic
materials are washed into a water body, bacterial
growth and metabolism can be stimulated to the
point that their consumption of oxygen will exceed
system inputs. For many bacteria, when the oxygen
is used up they can make use of alternate oxidants
such as nitrate, and oxidized forms of manganese,
iron, and sulfur. Unfortunately, many higher level
aquatic organisms are dependent on dissolved
oxygen, and when it is depleted they will die. Also
certain chemicals, for example ammonium, will
combine with dissolved oxygen and make it
unavailable. The oxygen depleting properties of
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 15
pollution are often measured as Biochemical Oxygen
Demand or BOD. BOD is determined by measuring
the oxygen loss of a water sample in a sealed bottle
kept in the dark for five days.
Aquatic Habitat Alteration
Even if urbanization had no impact on water
quality and quantity, there are often other severe
impacts on aquatic life. In many urban areas the
physical structure of aquatic habitats are modified
for municipal functions to the detriment of biological
functions. Trees removed from stream banks expose
the stream to less moderated temperature conditions
(higher in the summer, colder in the winter) (
Figure43
).Figure 43.
In a forested stream, trees moderate watertemperatures, support food webs, provide stream habitat
and stabilize the banks.
Removing trees also removes an important
source of fuel for detrital food webs. During
urbanization, stream channels are straightened, large
woody debris removed, and even the bottom
substrate may be covered with pavement (
Figure44
). These types of modifications remove criticalstream habitat and sterilize the aquatic ecosystem's
ability to support aquatic life. In extreme cases,
urban streams are "blacked out" by enclosing them in
pipes and covering them up.
Figure 44.
In many urban streams the forest has beenremoved and the aquatic ecosystems that they supported
can not exist. Photo by Judy Okay
Restoration
Overview
Restoring the urban forest can help to restore the
hydrological cycle and improve the functioning of
aquatic ecosystems. Significantly increasing tree
canopy coverage will reduce stormwater runoff and
peak flow, and increase the water storage capacity.
Urban forests are particularly critical near creeks,
streams, and rivers, where they act as riparian forest
buffers (
Figure 45).Forested riparian areas stabilize banks, uptake
nutrients, and provide shade, habitat, and food for
aquatic ecosystems. The magnitude of chemicals
used to support high maintenance urban landscapes is
overwhelming our efforts to treat polluted runoff.
Programs that encourage landscaping with native
forest trees can help because these trees will often
require less inputs of chemicals and water.
Urbanization alters and fragments aquatic
ecosystems, sometimes so severely that they cease to
function. More environmentally orientated planning
can prevent the problem, and reforestation is often
the key element in restoring the system.
Increasing Tree Coverage
Increasing or preserving tree coverage in an
urban watershed can have water quantity and quality
benefits. However, the scale of the restoration effort
needs to match the scale of the problem. A small
urban park, even one with a big tree will do little to
restore the water cycle to a big city (
Figure 46).Larger scale efforts are usually needed. Storm water
modeling with CITYgreen© software (American
Forests 1996) demonstrates the scale of coverage
needed with its expected water quantity benefits
(
Figure 47).Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 16
Figure 45.
Urban forests are particularity critical nearcreeks, streams, and rivers, where they act as riparian
forest buffers. Forested riparian areas stabilize banks,
uptake nutrients, and provide shade, habitat, and food for
aquatic ecosystems.
Figure 46.
Increasing or preserving tree coverage in anurban watershed can have water quantity and quality
benefits. However, the scale of the restoration effort needs
to match the scale of the problem.
Figure 47.
Computer models such as CITYgreen©software (American Forests 1996) can demonstrate the
value of the ecological services that trees provide.
Illustrations from CITYgreen
Their model predicts increasing tree coverage onan example residential development will reduce
storm water runoff and save money. With a 30% tree
cover the model predicts a 5 % decrease in runoff
volume, a 9 % decrease in peak flow and a 15 acre
feet/square mile increase in water storage. Potential
storm water storage treatment savings were
estimated to be about $120,000/square mile. When
the tree canopy coverage is increased to 70%, the
model predicts a 17 % decrease in runoff volume, a
27 % decrease in peak flow and a 48 acre feet/square
mile increase in storage. Potential storm water
storage treatment savings were estimated to be about
$390,000/square mile.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 17
There are some issues that must be considered
when evaluating the water quantity and quality
benefits of tree cover. The first is the timing of
benefits. Storm water engineers must design new
developments so that they meet hydrological
specifications for the first storm, not how the
development will respond many years later when the
canopy has grown to significant coverage. The
development must also continue to meet
hydrological specifications in winter when deciduous
trees have lost their cover. Storm water engineers
also know that canopy storage will be quickly filled
by the large storms that cause flooding events.
However, canopy storage can reduce the runoff of
the frequent smaller storms, and thus has the
potential to reduce pollutant loading to aquatic
ecosystems.
Riparian Forest Buffers
Riparian forest buffers have the potential to
reduce the amount of runoff and pollutants washing
into riparian ecosystems. They also stabilize stream
banks and moderate water temperatures. Preserving
or restoring forested riparian buffers also preserves
some of their ecological functions such as providing
terrestrial and aquatic habitats, and supplying the
source for detrital food webs. Many forested riparian
areas also contain flood plains and wetlands that
provide additional water quantity and quality
benefits. Forested riparian buffers are aesthetically
beautiful areas and can provide some forms of low
impact recreation.
There are three functional zones comprising a
well designed forested riparian buffer (
Figure 48).Zone 3 is a flat grassy area about 10m wide at the
urban-buffer interface (
Figure 49). Its majorfunction is to convert channelized urban flow into
sheet flow and slow water velocity to less than 0.3
m/sec. Zone 3 performs some settling, filtering, and
infiltration.
Figure 48.
There are three functional zones comprising awell designed forested riparian buffer. The zones are
designed to spread out and infiltrate storm water,
assimilate nutrients, and preserve the aquatic habitat.
Figure 49.
Zone 3 is a flat grassy area about 10m wide atthe urban/buffer interface. Its major function is to convert
channelized urban flow into sheet flow and slow water
velocity to less than 0.3 m/sec. Zone 3 performs some
settling, filtering, and infiltration. Photos are of the
"Difficult Run" urban riparian project, courtesy of Judy
Okay, Virginia Department of Forestry.
Zone 2 is a vigorously growing forest with a
width of 15 to 150m (
Figure 50). The required widthdepends on the load amount and the buffer slope,
soils, vegetation and level of allowed disturbance.
The major function of Zone 2 is to provide the
environment and contact time (at least 9 minutes) for
pollutant removal through sedimentation, filtration,
cation exchange, and plant uptake. In forest and
agricultural situations, selective removal of trees
from Zone 2 is recommended. Tree removal removes
nutrients and keeps the forest in a vigorous growth
stage.
Zone 1 is the mature forest at the land-water
interface and it controls the physical, chemical, and
trophic status of the stream (
Figure 51). Zone 1should be at least 10m wide. The major water quality
functions of Zone 1 are to stabilize the stream bank
and to shade and stabilize water temperatures.
Anoxic (without oxygen) organic soils in this zone
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 18
Figure 50.
This photo was taken down slope from Figure49 and shows the establishment of a zone 2 managed
forest. The left side is at planting and the right side is three
years after planting. Photo by Judy Okay, Virginia
Department of Forestry.
can remove nitrogen by the process of
denitrification, but uptake of other nutrients may be
balanced by litter fall. Zone 1 also provides detritus
for the aquatic food web and large woody debris for
critical aquatic habitat.
Figure 51.
Zone 1 is the mature forest at the land/waterinterface. It most directly controls the physical, chemical,
and trophic status of the stream. Photo by Judy Okay,
Virginia Department of Forestry.
Forested riparian buffers have their limits
(Herson-Jones et al. 1995). Pollutant removal
effectiveness is poor when the slopes are greater than
10% and with soils that have infiltration rates less
than 0.64 cm/hour. Disturbance (many recreational
activities) will greatly reduce their effectiveness. The
scale of the buffer needs to match the scale of the
source area. Poor performance can be expected with
high rates of channelized flow from large impervious
areas. Upstream Best Management Practices (BMPs)
may be required to scale the load to match the
buffer's capacity. Even under good conditions total
suspended solid removal is estimated to be 50%.
Source Control
The United States has 30 million acres of lawn.
On these lawns over 100 million tons of fertilizer
and 80 million pounds of pesticides are applied
annually (Borman et al. 1993) (
Figure 52). This rateof application is ten times the rate chemicals are used
per acre on US farms. The importation and
concentration of chemicals in urban watersheds
saturates and overwhelms our efforts to treat polluted
non-point source runoff. In an effort to reduce
harmful impacts to our aquatic ecosystems, many
new programs are focused on reducing the sources of
non-point pollution. These programs encourage
landscaping that uses and exports less water and
chemicals. Some examples of these types of
programs are BayScaping in the Chesapeake Bay
area (http://www.acb-online.org/bayscapes.htm),
Nature Scaping in the Portland, Oregon area
(http://www.enviro.ci.portland.or.us/ ), Florida
Yards and Neighbors
(http://207.0.223.151/extension_service/toc.htm),
and EPA's Green Communities
(http://www.epa.gov/greenacres/).
Figure 52.
Over 100 million tons of fertilizer and 80 millionpounds of pesticides are applied annually to U.S. lawns.
The general strategy of these programs is to
encourage landscaping that uses less pollutants and
produces less runoff. Native vegetation and ground
covers are recommended because they generally
require less inputs of water and chemicals (
Figure53
). In addition, exotic landscaping vegetation canescape and cause hydrological and other ecosystem
problems (
Figures 54 and 55) (See Chapter9-Invasive Plants
).Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 19
Figure 53.
This is an example of a yard that uses nativetrees and low maintenance ground cover. Native trees are
often adapted to local conditions and require less
supplemental inputs of water, fertilizer, and pesticides. In
this example the trees also provide pine needles for an
attractive and low maintenance ground cover.
Figure 54.
Exotic landscape plants can require morewater and chemicals and contribute to urban water
pollution. In addition, they can invade and damage natural
ecosystems. The Salt Cedar (Tamarix sp.) shown on the
right in the above photo (Zion National Park) has invaded
much of the Southwest altering hydrology and displacing
native plants.
Figure 55.
Salt Cedar has roots that can reach depths of30 meters and individual trees can use 800 liters of water
per day. Large stands of Salt Cedar can lower the ground
water below the level that native vegetation can reach.
They also adsorb salts from deeper soil layers and ground
water and transport it to their leaves (see above photo).
This salt increases the soil salinity above levels that many
native plants can tolerate.
The reduction of impervious surfaces by using
gravel driveways (
Figure 56) and on-site retentionlandscaping (
Figure 57) are examples of practicesthat will reduce the export of water and pollutants.
Figure 56.
Reducing the impervious surfaces at a homeby having an attractive gravel driveway instead of an
impervious paved one, will significantly reduce the
amount of water and pollutants that runoff property. The
cumulative impact of many citizens reducing their pollutant
load can make the restoration of aquatic ecosystems
possible.
Aquatic Habitat Improvement
The impact of urbanization on aquatic
ecosystems goes beyond the damage caused by
increased runoff and poor water quality. Frequently,
urbanization degrades the physical aquatic habitat by
altering its morphology, changing or even paving the
bottom substrate, and altering light inputs. Intakes for
domestic water supplies and dams will drastically
disrupt stream continuity. Aquatic systems are parts
of larger ecosystems. Poor urban planning can break
links to other systems that provide essential
functions to aquatic systems. For example, filling in
wetlands and flood plains can eliminate breeding and
nursery habitat, and removing upland forests
eliminates an important source of energy for detrital
food webs. Conversely, forested aquatic ecosystems
provide essential elements for upland ecosystems and
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 20
Figure 57.
Large stormwater treatment facilities oftenhave poor pollutant reduction performance. A better
solution is to keep stormwater on site and allow it to be
filtered by the soil. This picture shows a "rain garden"
where runoff from the roof and driveway will be retained
and pollutants filtered out by the soil. Photo by Judy Okay,
Virginia Department of Forestry.
they often function as crucial corridors necessary for
the survival of many species.
Figure 58
shows an urbanized stream that wouldnot function with even the best water quality. Stream
morphology has been drastically altered, the bottom
substrate paved over, and stream-side communities
have been eliminated.
Figure 58.
Even with the best of water quality thisurbanized stream will be a non-functioning ecosystem.
The stream morphology has been altered, the bottom
substrate paved over, and stream communities have been
eliminated.
In
Figure 59 important stream habitat has beenrestored by importing large woody debris directly
into the stream. Large woody debris provides
important nesting, cover and substrate for aquatic
life. Stream vegetation has been replanted to provide
shade for cooler and more stabilized water
temperatures and to provide detritus for food webs.
Figure 59.
In this stream, important habitat has beenrestored by importing large woody debris directly into the
stream. Large woody debris provides important nesting,
cover, and substrate for aquatic life. Streamside
vegetation has been replanted to provide shade for cooler
and more stabilized water temperatures, and to provide
detritus for food webs.
Engineering is necessary for a city to function
properly. Many cities are discovering that with a little
extra care, engineering functions can be combined
with ecological principles to provide functioning
aquatic habitats. For example, retention ponds are
used in urban areas to provide storage for increased
runoff and to settle out particulate pollutants.
Although the pond in
Figure 60 may perform someof those functions, it provides little if any aquatic
habitat. On the other hand, the detention pond in
Figure 61
incorporated wetlands and forests toprovide ecological functions as well as engineered
treatment of urban storm water.
Figure 60.
Retention ponds are used in urban areas toprovide storage for increased runoff and to settle out
particulate pollutants. Although this pond may perform
some of those functions, it provides little if any aquatic
ecosystem habitat.
Urban parks also provide an opportunity for
aquatic habitat restoration or preservation. Often
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 21
Figure 61.
On the other hand this pond was designed tobe a functioning ecosystem.
urban parks contain a significant amount of
impervious area and high maintenance vegetation
that can cause degradation of associated aquatic
habitat (
Figure 62). With careful design forestedurban parks can provide recreational opportunities as
well as a functional aquatic habitat (
Figure 63) .Figure 62.
Figures 62 and 63 are parks in Mt. Dora,Florida. Although this traditional urban park provides
needed recreation activities, the natural habitat has been
paved or grassed, and the water features only provide
limited aesthetic value.
Figure 63.
Nearby Palm Island Park, also at Mt. Dora,Florida, has been left as an intact ecosystem. A board walk
allows people to explore the upland/wetland/aquatic
wonders with little negative impact to the hydrological
cycle and the ecosystems dependent on it.
References
American Forests. 1996. CITYgreen© Urban
Ecosystem Analysis Software. American Forests.
Washington, DC.
Beaulac, M. N. and K. H. Reckhow. 1982. An
examination of land use-nutrient export relationships.
Water Resources Bulletin. 18:1013-1023.
Bormann, F. H., D. Balmori, and G. T. Geballe.
1993. Redesigning the American lawn. Yale
University Press.
Brooks, K. N., P. F. Folliott, H. M. Gregerson, J.
L. Thames. 1991. Hydrology and the management
of watersheds. Iowa State University Press, Ames.
392 pp.
Environmental Protection Agency. 1993a.
Guidance specifying management measures for
sources of nonpoint source pollution in coastal
waters. USEPA #840-B-92-002. Washington, DC.
Environmental Protection Agency. 1993b.
Nonpoint Pointers. USEPA #EPA-841-F-96-004,
Washington, D.C.
Herson-Jones, L. M., M. Hertaty, and B. Jordan.
1995. Riparian buffer strategies for urban
watersheds. Metropolitan Washington Council of
Governments Environmental Land Planning Series
No. 95703. 101 pp.
Hewlett, J. D. 1982. Principles of forest
hydrology. The University of Georgia Press, Athens.
183 pp.
Kimmins, J .P. 1997. Forest Ecology: A
foundation for sustainable management. Printice
Hall, Upper Saddle River, New Jersey. 596 pp.
National Academy of Sciences. 1969.
Eutrophication: Causes, Consequences, Correctives.
Chapter 6: Restoring the Hydrological Cycle in the Urban Forest Ecosystem 22
Proceedings of a Symposium, National Academy of
Sciences, Washington, D.C.
Novotny, V., H. Olem. 1994. Water Quality:
Prevention, Identification, and management of
diffuse pollution. Van Nostrand Reinhold, New
York. 1054 pp.
Riekerk, H., H. L. Gholz, D. G. Neary, L. V.
Korhnak, and S. G. Liu. 1995. Evapotranspiration of
pineflatwoods in Florida. Finial Report to USDA
Forest Service Southern Forest Experiment Station.
37 pp.
Schueler, T. R. 1992. Mitigating the adverse
impacts of urbanization on streams: A
comprehensive strategy for local government. In: P.
Kumble and T. Schueler (eds). Watershed
Restoration Source book: Collected Papers Presented
at the Conference; Restoring Our Home River: Water
Quality and Habitat in the Anacostia. Publication
#92701 of the Metropolitan Washington Council of
Governments, Washington, DC.
Shahane, A. N. 1982. Estimation of pre and post
non-point water quality loadings. Water Resources
Bulletin. 18:231-237.
Thompson, P., R. Adler, and J. Landman. 1989.
Poison Runoff. National Resource Defense Council.
Washington, D.C. 484 pp.
Welsch D. J. 1991. Riparian forest buffers:
Function and design for protection and enhancement
of water resources. USDA Forest Service
Northeastern Area Document NA-PR-07-91. 23 pp.
Chapter 7: Site Assessment and Soil Improvement1
Kim D. Coder
21. This is Chapter 7 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Kim D. Coder, Professor, University of Georgia, School of Forest Resources, Athens, GA 30602-4356. http://www.forestry.uga.edu/efr
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
The first step in any restoration project is to gain
an appreciation of the site. The site needs to be
defined, delineated, inventoried, and assessed for the
restoration goals and objectives to be successfully
accomplished. A key component in assessing sites
for ecological restoration is developing, both for your
own reference and others, a story of site development
or a site picture. This is called determining the site
context. Each site should be assessed for its
ecological and societal context. An ecological
management unit (EMU), the smallest treatable unit
-- smallest restorable unit -- must be the focus for
restoration management activities. Through the
assessment process, the primary concern is the
ecological restoration of the EMU. An initial site
assessment should include inventory of resources,
space, size, diversity, temporal changes,
disturbances, stress, natural cycles, organic matter,
management, form, and development of a final
action-list. However, it is just as important to the
success of any restoration project to include the stake
holders, decision-makers and social systems in all
phases of the project. Assessment is a part of the
planning and management process, not a disjunct and
separate piece. Remember that every site and
situation will be different.
Another decisive step to be considered in a
restoration project is soil health evaluation and
improvement. Soil health management is essential
for (and a part of) healthy and sustainable ecological
systems. A number of soil features become degraded
or destroyed over time in highly stressed
environments. An average urban soil usually has few
essential elements, poor drainage, erosion, soil
compaction, a heavy texture, little organic matter, and
a low diversity and small number of beneficial
organisms. Restoration activities need to be
prescribed carefully in trophic level order to assure
success -- in other words, truly start at the bottom
and restore upward. The soil is the foundation upon
which we restore ecosystem functions and structures.
The soil attributes to be restored successfully include
texture, structure, bulk density, water, aeration,
element holding capacity, essential elements, organic
matter, contamination, and trophic enrichment.
Introduction
The urban forest is the tie which binds humans to
life sustaining ecological systems. Beyond the urban
forest are the rocky and barren hardscapes of paved
and roofed deserts. We have interspersed these
buildings and roads with a few parks and road-side
trees which are often maintained with too many
resources and much energy. It is time to take back a
Chapter 7: Site Assessment and Soil Improvement 2
heritage of forest and field, and live more gently
among the trees. Restoration of these altered and
often exhausted ecological systems will not be quick
or easy. Yet the results and rewards are important to
the future health of our cities and communities.
A restoration process includes an understanding
of basic rules and perceptions regarding a
community's ecological resources and how to plan
and make decisions which impact these resources.
Other chapters in this CD-ROM review the
ecological principles and processes as well as the
development of a management plan. However, one
of the first steps in the restoration process is
assessing the site's resources. The soil is probably
one of the most damaged parts of the ecosystem in
the urban forest, therefore, restoring soil health of a
site is a critical step to successful restoration. The
first part of this chapter,
Site Assessment, isconcerned with the steps involved in this assessment.
The second part of this chapter,
Soil Improvement,presents the principles of soil health and methods for
its restoration.
Site Assessment
Every surface and space in the urban forest is a
resource containing site. Most sites are severely
lacking in many resources, either through a lack of
quantity or quality. Many sites have experienced
disturbances such as hydrological alterations,
invasion of exotic species, compaction from
recreational activities and fragmentation. In
restoring these sites, urban foresters seek to restore
resources and processes. The first step in any
restoration project is to gain an appreciation of the
site. The site needs to be defined, delineated,
inventoried, and assessed even before the goals and
objectives for restoration are developed. Having a
clear picture of the site is essential to describe and
defend restoration options and plans to peers,
stake-holders, decision-makers, site workers, and
resource owners/controllers
(Figure 1).Figure 1.1 Photo by Mary Duryea
Figure 1.2 Photo by Larry Korhnak
Figure 1.
Having a clear picture of the site is essential todescribe and defend restoration options and plans to
peers, stake-holders, decision-makers, site workers, and
resource owners/controllers.
Site components include:
• life resources
• life connections,
• biological units,
• climate,
• topography,
• geology, and
• past history (disturbances, stresses, and
mechanical damage).
What were the past historic ecosystems like on
the site? Using maps, interviews, GIS and other
resources, the historic ecosystems on the site need to
be described with their flora and fauna and natural
disturbances. Then the current ecosystems need to
be described; what is there now and why? And
finally how does this site fit into the landscape and
the master plan for the region? Does it have regional
Chapter 7: Site Assessment and Soil Improvement 3
significance, ecological significance, and/or social
significance
(Figure 2)?Figure 2.1 Photo by Mary Duryea
Figure 2.2 Photo by Larry Korhnak
Figure 2.
Maps, GIS and other resources can be usefultools for assessing past and current site conditions in a
restoration project.
Site Context
A key component in assessing sites for
ecological restoration is developing, both for your
own reference and others, a story of site development
or a site picture. This is called determining the site
context. How did the site arrive at its current
condition? Included in this assessment is
determining what it was like in the past. And finally
an evaluation of the possibilities for restoration.
Developing a full description of the site, its attributes
and processes, is critical for identifying the
possibilities and constraints to restoration.
Practically speaking, a restoration site might be a
perfect biological or ecological candidate, but
socially unacceptable for restoration. Each site
should be assessed for its ecological and societal
context.
The ecological story of a site must be
determined in any assessment process. The
ecological context of a site includes, but is not limited
to:
•
Anthropogenic changes to the ecosystems onthe site.
•
Site history (biological, physical, chemical),including presence of toxins, hydrological
alterations, substrate changes such as impervious
layers, soil interfaces, and past abuse.
•
Soils, including fill, compaction, interfaceproblems, depth, drainage, aeration,
contamination, and flooding regimes.
•
Topography/slope, including cold pockets, soildepth, water relations, and wind impacts.
•
Energy balance, including incoming radiationand its distribution/dissipation, urban heat island
effects, wind and direction, light quality and
quantity, and night lighting.
•
Water balance, including relative humidity,precipitation, evaporation, irrigation, and site
water demand.
•
Biological components (animals, plants,microbes, etc.) and their interactions, including
pests, competition, allelopathy, disturbance,
succession, and mechanical damage.
•
Genetics, including cultivars, natives, exotics,and genetic interactions with the environment
(response to stress, strain, abuse, and pests).
•
Space, including space for growth, expansion,crowding, stagnation, and space to structurally
support life-forms.
•
Climate, including precipitation, temperature,wind, pollution deposition, wind/pest
interactions, variability (winter to summer or
Chapter 7: Site Assessment and Soil Improvement 4
day to night), drought concerns in summer and
winter, lag effect (e.g., time delay) of symptom
expression, and problems of scale.
Climate is a critical feature of the site to
understand. In general, urban climates (local to
meso-climate scales) are significantly different than
average climate data collected at regional weather
stations. Urban climates, when compared to national/
regional averages, have: 25% lower wind speeds
from obstructions; 12% greater calm days (air mass
stagnation); 1.5 degrees F greater annual
temperature; 2.7 degrees F greater minimum winter
temperature; 7% greater precipitation events (more
precipitation events but less per event); 5% lower
relative humidity (geometrically increased site
water demands); 7% greater cloudiness; 17% less
incoming radiation (clouds and pollution); and, 10
times more common pollutants (Craul 1992). For
further information check Craul's urban soils books
listed in the
Suggested Readings section.In general, the urban climate is drier and hotter,
with less usable water, more pests, and more
pollution than normal. All these climate factors
combined lead to greatly increased stress on
ecosystems.
The societal context or story of a site must be
determined in any assessment process. The societal
context of a site includes, but is not limited to:
•
Anthropogenic changes of management, suchas changes in ownership from private to public
with different management goals, objectives and
implementation.
•
Historical significance, includingarchaeological importance as well as more
recent cultural significance.
•
Social significance, including public / privateownership, emotional attachment, and pride or
remorse of ownership.
•
Aesthetics, considering the interaction betweenecology and aesthetics. In the past we have
accepted great architectural and aesthetic
trade-offs disregarding local site ecology and
biological functions.
•
Political significance, including delineatingwho takes credit, pays bills, and is included.
•
Economics, including analysis of valuesproduced versus costs.
•
Site circulation and access, includingmovement around and across the site, how
access is allowed, and security issues.
•
Liability and environmental vandalism,including safety, noise pollution, traffic control,
and asset loss.
•
Regulatory environment, including zoning,endangered species, wetlands, and erosion.
•
Cultural practices and public awarenessincluding herbicides, tree removals, topping, and
perceptions of existing programs.
Once a site can be viewed in its ecological and
societal context, an ecological restoration process
can be fitted within the identified constraints to
maximize ecological and biological values in a
sustainable manner. An urban forester should list
site constraints in a carefully prepared management
plan by prioritized order from the most limiting to
least limiting. For each constraint identified in the
management plan, plans for dealing with the
constraint need to be included.
Management Units
In our assessment system for identifying and
prioritizing process and site constraints, a
management unit must be identified and delineated.
Without mapable management units, discrete
boundaries for treatments, and accurate planning
edges, management confusion can exist as well as
administrative accountability problems. What is the
space and its dimensions for your restoration plan?
What is the ecological management unit?
An ecological management unit (EMU), the
smallest treatable unit -- smallest restorable unit --
must be the focus for restoration management
activities. An EMU is a human-defined, limited area
which can include one or more ecosystems. Site
assessment requires identification, delineation, and
declaration of an ecological management unit
Chapter 7: Site Assessment and Soil Improvement 5
(EMU). In natural resource management, a written
management plan can not be fulfilled without
understanding what is being managed, for what
purpose, and its size, shape, or form. From an
ecological restoration standpoint, the criteria we
must use to apply, maintain and evaluate our actions
depend upon our abilities to delineate an ecological
management unit.
The necessity for setting boundaries and
management limits is self-evident for any restoration
manager. Unfortunately, many academic concepts
of ecosystems fail to provide walls, limits or
boundaries. The landscape includes many
interconnected smaller ecosystems of various spacial
scales, overlapping with each other and the
restoration site. The conceptual problems with these
ideas of ecosystems is which one you are trying to
restore? What sub-division? What portion? How do
you declare victory, evaluate actions, or prepare
budgets if the spacial extent of the ecological
restoration area is nebulous? Discrete boundaries for
the restoration project are critical to planning,
implementing and the success of the project.
Politics and Science
Through the assessment process, the primary
concern has been the ecological restoration of the
EMU. However, it is just as important to the success
of any restoration project to include the
stake-holders, decision-makers and surrounding
social systems in all phases of the project
(Figure 3).It is also critical to the project that science and
politics remain separated. An ecological restoration
project needs to compartmentalize and keep separate
ecological science from social, cultural and
economic-based decision making. Physical,
chemical, and structural facts need to be clearly
separated from human feelings, needs and value
judgements. Ecology is apolitical in the natural
world. Politicizing ecology can destroy objectivity
in decision-making and allow mis-use or selective
use of scientific information. Professional respect
and accountability can be eroded quickly if you lose
sight of the science and political separation.
Figure 3.1 Photo by Rob Buffler
Figure 3.2 Photo by Mary Duryea
Figure 3.
It is important to the success of any restorationproject to include stake-holders, decision-makers and
surrounding social systems in all phases of a project.
The Assessment Process
There are many tools and methodologies for
assessing damaged and exhausted EMUs to
determine whether they are viable candidates for
restoration, and to identify the magnitude of efforts
required for a restoration project. Presented here is a
basic checklist for an assessment process. It is
assumed you have already set goals and objectives,
and identified a number of constraints (see
Chapter5 - Developing a Management Plan
). Assessmentis a part of the planning and management process,
not a disjunct and separate piece. Remember, every
site and situation will be different. You are
encouraged to develop assessment systems which
best serve your ecological and political situations.
Chapter 7: Site Assessment and Soil Improvement 6
The following assessment process has been used
successfully for urban and community forest sites,
land development interface sites, and for damaged or
abused environmental management sites in Europe
and North America. This assessment process is
presented as a guide to collecting information for
planning restoration activities in an ecological
management unit. The following information must
be determined:
1. Quantify
The first step is to define and delineate (on maps
and on the ground) the EMU and its context in the
landscape. This step is an inventory of resources,
processes and rates of change, and a classification or
analysis of what exists (quantify and graphically
classify).
2. Size
Assess the EMU and determine if it is large
enough to sustain the values and outputs expected.
This step is an assessment of scale problems
including biodiversity, genetic variability,
reproductive spheres, and colonization potential.
3. Space
Assess the spacial relationships between the
EMU and other ecosystems in the landscape for
current and future connectivity, fragmentation, and
ecological integrity. Record quality and quantity of
information on ecological gaps, fragments, corridors,
and ecotones.
4. Diversity
Assess the variability, density, and diversity of
species and their habitat. Included should be
information on natives, exotics, and habitat
composition for key species.
5. Time
Temporal changes across a site will be many.
Assess the pattern and timing of when individuals
and species are expected to age and die, and
successional patterns for the site (See
Chapter 4 -Plant Succession and Disturbances
).Considerations are life-spans of key and dominant
species, current age classes and structures, and how
life-forms are removed or enter a site.
6. Disturbance
Assess historical and present disturbance
regimes including the type, intensity, and frequency
(see
Chapter 4 - Plant Succession andDisturbances
).7. Stress
Assess historic and present stress components of
the site. Stress includes anthropogenic problems,
competition, allelopathy, pests including invasive
species, and environmental constraints to survival
and growth (see
Chapter 9 - Invasive Species).8. Natural Cycles
Assess the effort and consequences of activities
to recover historic material and energy cycling
processes. Assess how to restore the natural cycles
such as nutrient cycling to encourage a more natural
support (lower maintenance) of site functions and
move away from human-centered support. Take
special care in observing energy flow, the hydrology
on the site, and nutrient status and processing (see
Chapters 2 and 6 - Ecological Processes
andRestoring the Hydrologic Cycle
)9. Organic Matter
The presence of organic matter on the site is
critical to the nutrient cycle and the health of the site.
Special concern should be targeted at large woody
debris and soil organic matter.
10. Management Resolve
Assess on-site and within the management
system the appreciation of ecological realities
(sometimes natural ecosystems may appear messy,
unkept, or chaotic compared to sites with single
species or grassy parks) and acceptance of change.
11. Action Check-List
The principle means of restoring the EMU can
include:
Chapter 7: Site Assessment and Soil Improvement 7
• Re-instituting successional processes.
• Re-instating disturbance regimes.
• Enriching the genetic resources (living things),
including:
• Adding and/or replacing "key" organisms
(trees, vertebrates, fungi, arthropods,
worms, etc.)
• Modifying native systems to include more
trophic levels.
• Improving site resources, including:
• Increasing organic matter (woody
biomass, soil and litter).
• Improving soil exchange capacity
(element cycling and holding).
• Improving soil health (pore space and
structure).
• Increasing water availability (cycling, use,
flow,
• Modifying or enriching nitrogen cycling.
• Altering site light resources (light and
shade management).
• Minimizing stress on key species.
• Contain or eliminate heavy metals.
• Control pollution.
• Control heat.
• Control exotics.
• Physically protect site from mechanical
and chemical damage.
• Control oxygen availability and water
drainage trade-offs in soil.
Soil Improvement
Introduction
Soil health management is a very critical portion
of a renovation process to sustain ecological
functions. Soils are the primary contact point
between living organisms and are a biologically,
chemically, and physically active portion of the
environment. Soils are the ecological interface for
materials and energy exchange, and a matrix that
supports, houses, and stores essential elements and
living things. Mineral, dead, near-dead, and living
things are all held in a thin layer of ecological volume
called soil. Conceptually, a soil for restoration can be
considered a matrix of living things rather than an
engineering material. Soil is the basis for urban
ecosystem productivity.
The resources soil provide to support ecosystem
productivity include:
• growth materials (15 of 18 essential elements
plus water from the soil,)
• transport and storage of growth materials,
• buffer change and variability,
• physical and chemical protection,
• structural growth matrix, and
• primary energy exchange surface.
Good soil management is essential for (and a
part of) healthy and sustainable ecological systems.
A number of soil features become degraded,
destroyed or exhausted over time in highly stressed
environments. Soil assessments concentrate on those
chemical, physical, and biological features of soil
resources which can limit colonization, survival, and
growth of living things. Restoration activities need to
be prescribed carefully in trophic level order to
assure success--in other words, truly start at the
bottom and restore upward. The soil is the
foundation upon which we restore ecosystem
functions and structures
(Figure 4).Chapter 7: Site Assessment and Soil Improvement 8
Figure 4.
Soils form the basis for urban forest ecosystemproductivity. Photo by Larry Korhnak
Ideal Soils
Ideally a soil is composed of materials and space
in roughly equal proportions. A "perfect soil" for
ecological development is considered to have 45%
mineral materials and 5% organic materials (living
and dead), and 50% pore space divided equally
between large air-filled pores and small water-filled
pores. A perfect soil has horizontal layering
developed through an assortment of genesis
processes. These layers are called "horizons"
(Figure 5).
Horizonation requires time to developfrom the last major disturbance on the site. As such,
most urban soils have little horizonation, but do
develop these characteristics if allowed to remain
relatively undisturbed.
Figure 5.
Ideal soils have horizons or zones wheredifferent process occur such as organic matter
breakdown, weathering, leaching, and material
accumulation. Photo by Larry Korhnak
An ideal soil profile (from the surface
downward) would have four horisons as seen in
(Table 1).
Most urban soils deviate wildly from idealsoil features, but by knowing theoretical limits,
restoration changes can be judged for value.
Table 1.
An ideal soil profile.Horizons Description
A horizon surface soil with maximum organic
matter accumulation, good porosity,
many living organisms, most active
tree roots, and represents a zone
leached by precipitation and soil
weathering factors
B horizon "subsoil" where clays accumulate
C horizon oxidized parent material
D horizon unoxidized parent material
Urban Soil Features
Urban soils have many unique features. Urban
soil features which are most limiting to a restoration
process are listed below:
• great vertical and horizontal variation,
• compacted structure,
Chapter 7: Site Assessment and Soil Improvement 9
• modified infiltration, percolation and water
holding capacity,
• crusting or water repellent surface,
• pH changes (usually increasing pH),
• restricted aeration and drainage,
• impotent or disjunct element cycling,
• modified ecology of soil organism activities
(no organic material),
• toxins and contaminants,
• soil temperature changes, and
• reduced mineralization rates (from organic
matter) and accelerated nitrification.
An average urban soil is disturbed and highly
variable caused by digging, cutting, filling, trenching
and scraping
(Figure 6). The average urban soil hasfew essential elements, poor drainage, and a
compacted, heavy texture. Within the soil are many
blatant, sharp interfaces between layers and parts.
The average urban soil has little organic matter and
surface litter with a low diversity and small number
of beneficial organisms. Erosion remains a terrible
problem.
Figure 6.
Urban soils are often altered by digging, cutting,trenching, scraping and, as shown here, by filling. Photo
by Larry Korhnak
The Manageable
10The soil attributes that affect and control soil
resources, and present the most potential for
ecological restoration success are:
1. texture
2. structure
3. bulk density
4. water
5. aeration
6. element holding capacity
7. essential elements
8. organic matter
9. contamination
10. trophic enrichment
Each of these restoration attributes represent
opportunities for a manager to be successful.
1. Soil Texture
Texture is the relative percentage of sand, silt,
and clay-sized particles in the mineral portion of the
soil. Most soils are a mixture of various particle sizes
and distributions. Texture directly affects water and
oxygen, and indirectly affects essential elements.
The clay component of a soil dominates soil activity.
As clay contents approach and exceed 20-25% in the
soil particle mixture, the chemistry and limitations of
the clays control soil attributes
(Figure 7).Soil texture can be modified by amendments but
it is not practical for large scale projects. For
example, on an average house lot the top foot of soil
weights 400 tons. To convert soil texture in this zone
from a clay soil to a sandy clay loam requires the
removal of 120 tons of the clay soil and its
replacement with 120 tons of sand. At the one-foot
depth mark, the interface between the first foot and
second foot of soil would be limiting to tree growth.
The texture change provided by this amendment
process successfully increased aeration pore space.
It is clear from this example that soil texture changes
are of little practical importance other than in beds,
containers, or planting holes.
One area where texture is critical to
understanding restoration processes is at textural
interfaces. An interface is where soil texture changes
Chapter 7: Site Assessment and Soil Improvement 10
Figure 7.
Texture is the relative percentage of sand, silt,and clay-sized particles in the mineral portion of the soil.
over short distances (less than 1- 4 inches). These
interfaces are most often horizontal layers, but can
be lens or vertical layers which texturally vary from
adjacent layers. Textural interfaces below the soil
surface can provide many gas and water exchange
limitations.
There are four primary texture interface types:
Type 1 Interface
= finer texture soil tocoarser textured soil (small pores to large
pores) -- water can not move from one layer
to the next until the upper fine-textured layer
is saturated (water will remain in the fine soil
if it is at less-than-saturation.) Bathtub effect!
Type 2 Interface
= coarser textured soil tofiner texture soil (large pores to small pores)
-- water movement is away from coarser
textured soil and limited by water movement
into finer soil (water can build-up at the
interface if in excess, but continues to move
into finer soil.) Drought effect!
Type 3 Interface
= coarse horizontal orvertical layers of gravel, large sand, organic
materials, etc. -- water must saturate soil
above the coarse layer before moving into the
coarse layer (water will perch above the
coarse layer.) Because of hydraulic
conductivity processes, the tree depends upon
local water and local essential elements. This
interface limits rooting area from the bottom.
Perched water, limited oxygen flow!
Type 4 Interface
= gradual texture changeswhere mixing or incorporation has spread out
the interface distance -- good interface width
for minimizing water problems is 1 foot. (1- 4
feet depending on texture changes.)
Working examples utilizing trees showing the
importance of interface problems to restoration work
follow. Tree #1 is planted in a native coarse soil with
a root ball composed of fine textured soil. Water is
added immediately above / over the root ball.
Because of the interface (rapidly changing average
pore sizes), water can not move across the interface
until the soil in the root ball saturates. The result is
the tree sits in a near-saturated soil much of the time.
(Type #1 Interface). An additional result is water
applied to the site will not necessarily enter the root
ball leaving the tree drought stricken.
Tree #2 is planted in a native fine soil with a root
ball which is composed of coarse textured soil.
Water added directly above the root ball will move
across the interface, although slowly. Water will be
drawn into the surrounding fine textured soil from
the large pore spaces of the root ball soil. The result
is a tree under low soil water conditions much of the
time. (Type #2 Interface).
Tree #3 is planted in native fine soil with a root
ball composed of fine textured soil and a layer of
gravel in the bottom of the planting hole. Water will
be perched above the coarse layer and move through
only as the soil above saturates. The result is water
and oxygen movement through the soil is disrupted.
(Type #3 Interface). A tree will have a limited
rooting area until it breaks through the coarse layer.
Depending upon the scale and duration of water and
oxygen movement disruption in the soil, roots may
never escape soil constraints.
2. Soil Structure
Structure in soil is represented by aggregates of
the basic texture particles in specific shaped
structures. The primary types of soil structure are
platelike, prismlike, blocklike and spheroidal. Soil
particles are held in these structural aggregates by
Chapter 7: Site Assessment and Soil Improvement 11
adhesive forces from organic, colloidal, or metal
oxide coatings. Soil structure can be modified by
amendments.
Organic matter amendments (composted organic
material not merely organic mulch) promote
granulation in both sandy and clay soils. Organic
materials added to sandy soils generate more small
pore development, which sandy soils lack. Organic
materials added to clay soils generate more large pore
development, which clay soils lack. In both coarse
and fine soils the improvement in structure from
organic matter additions improves the availability of
water and oxygen
(Figure 8). Care must beexercised when working with clay soils because they
are very susceptible to compaction of pore spaces
and destruction of structural units when wet.
An example of soil improvement through
structural change could be compared to the attempted
textural change example given above. The example
cited modifying water and oxygen availability in the
top foot of an average house lot. Adding 1.2 tons of
composted organic material to the soil will have a
similar effect as replacing 120 tons of soil with sand.
A simple conclusion is restoration can be successful
and cost-effective by concentrating on soil structure
changes rather than soil texture changes. A critical
feature of organic matter additions is do not allow
sub-surface layers to develop.
Figure 8.
Organic matter can add beneficial structure toclay and sands. As shown here organic matter gives sand
a granular structure that improves water availability. Photo
by Larry Korhnak
3. Bulk Density and Pore Space
Bulk density is the relative density of a soil
including its pore space volume. It is measured by
dividing the dry weight of a soil by its volume. If
soil was just mineral material, an average density of
common minerals would be 2.65 g/cc. As we
discussed earlier, half of an ideal soil should be pore
space (voids or spaces between solid soil
materials)-- which makes ideal bulk density 1.3 g/cc
(50% pore space.)
The characteristics of pore space varies by soil
texture. Sands have many large pores filled with air.
Clays have many small pores filled with water. Clays
have greater total pore space than sand but it is filled
with tightly held water. For example the typical air
filled pore space of a drained soil would be 35% for
sand, 25% for silt, and only 15% for clay.
Unfortunately urban soils are moderate to
heavily compacted by footsteps, light vehicles, and
heavy construction vehicles. This compaction
shrinks large pore spaces which usually hold air, as
well as decreasing total pore space (increasing bulk
density.) Depending upon soil texture and structure,
tree root growth problems can be initiated with only
small increases in bulk density
(Figure 9).Figure 9.
Bulk density in urban soils is often increased bycompaction. The decrease in pore space can cause tree
growth problems. Photo by Larry Korhnak
Chapter 7: Site Assessment and Soil Improvement 12
For example, roots have difficulty physically
penetrating beyond a bulk density of 1.75 g/cc.
Oxygen availability constrains tree root growth as air
pore space drops below 15% volume of the soil.
Table 2
presents soil attributes where tree rootgrowth begins to be significantly limited for each soil
texture class.
Compaction prevents root and soil functions
essential to life. Compaction is found across all
types of sites. Construction sites have been found to
average 60% greater bulk density than neighboring
native soils. A rule of thumb is an increase in bulk
density by 1/3, causes a loss of 1/2 root and shoot
growth. Compaction is not easily reversed. Harvest
sites (logging decks, major skid trails, and forest
road trails) can be effectively mapped after 40 years
based only upon soil compaction and tree growth
data. Time does not heal all.
Table 2.
Soil attributes where root growth begins to besignificantly limited for each soil texture class.
soil
texture
root-limiting
bulk
density
g/cc
root-limiting
% pores
filled with
air
% total pore
space in
soil
sand 1.8 24 32
fine
sand
1.75 21 34
sandy
loam
1.7 19 36
fine
sandy
loam
1.65 15 38
loam 1.55 14 41
silt loam 1.45 17 45
clay
loam
1.5 11 43
clay 1.4 13 47
There have been many compaction treatments
proposed over the years. Surface tillage as deep as
possible (at least 8 inches) and sub-soiling (winged
bars below 16 inches), can be used when no tree
roots are present to decrease bulk density. A soil can
be amended with non-compressible, porous materials
like washed flyash to provide pore space. Soil can
also be amended with large gravel or small blocky
stones to provide large airspaces and a bearing
surface.
When trees are present, mulching can be used to
minimize continued compaction pressure, and
dissipate raindrop energy and surface erosion. Core
aerators made for deep penetrations (12-16 inch
long) can be effective but in heavily compacted soil
may not be effective beyond 3-5 inches deep and may
be difficult to use. Punch aerators create open soil
space but compact the side of the surrounding hole.
Surface aerators (2-4 inches deep) generate a low
bulk density zone over a compacted zone just below,
thus presenting a very limited root colonization area.
Aerators are undergoing a major conceptual
re-engineering period for assisting with restoration of
severely compacted soils.
The primary means of reducing compaction
problems both concentrate on generating more
surface areas/ecological volume for root initiation
and colonization. The two methods are vertical
mulching and radial trenching. Vertical mulching
uses a series of vertical holes augured into the soil to
a depth of 14-24 inches on 2-3 feet centers under the
drip line of the tree. The treatment can be expanded
into soil areas useful for root colonization. The 1-2
inch diameter soil cores should be backfilled with
washed, graded, and non-compressible materials
open to the atmosphere. A composted organic matter
and mineral light mix would be ideal with an organic
mulch placed over the surface. Over time, material
subsidence will require refilling holes.
Radial trenching uses a trencher or thin
back-hole to dig trench lines from 2 - 14 inches wide.
Each trench line begins on the ground surface 4-6
feet away from the tree trunk. As the trencher moves
outward from the trunk area, the cutting head is
allowed to dig downward to its operating depth. The
trenches are backfilled with washed, graded, and
non-compressible materials open to the atmosphere.
Chapter 7: Site Assessment and Soil Improvement 13
A composted organic matter and mineral light-mix
would be ideal with an organic mulch on the surface.
Various growth stimulators and soil enrichment
materials may be added. Five to six trenches are
initiated near the trunk and extend out to one and
one-half the drip-line distance. As the distance
between trenches increases, intermediate new
trenches can be added, depending upon site and soil
limitations.
4. Water
Water is held around the soil particles and within
soil pores. Water sticks together and is pulled
through a soil to the top of a tree by the process of
transpiration. Depending upon soil texture, some
water is held too tightly by soil particles to be
extracted by trees. The traditional soil-water terms
are defined in
Table 3:Table 3.
Definition of soil-water terms.Term Definition
Field
capacity
the amount of water held against
the force of gravity
Permanent
wilting point
water content level where the soil
holds water so tightly that trees can
not extract it (water contents at or
below this level are unavailable to
the tree)
Tree-available
water
water present in soil between field
capacity and permanent wilting
point that trees can extract from the
soil
Tree-available water varies by soil texture.
Sandy loams probably have the greatest amount of
water available to a tree of any soil texture. Clays
contain more total water than other texture types, but
most of this water (up to 75%) remains tied tightly
to the clay surfaces and micro pores, and so,
unavailable to a tree. Sands contain little water but
what is present is almost all available for tree up-take
and growth.
Water movement can be disrupted in urban soils.
The many textural/structural interfaces within urban
soil profiles, allow many water and oxygen
availability problems to exist. In highly disturbed
urban soils with many interfaces, water around the
roots is critical to tree survival. Even the process of
installing irrigation (depending upon backfill) can
change water flow through the soil. Irrigating to
correct turf water shortages will usually over-water
trees. Trees should be separately zoned for irrigation
in a landscape.
As site water inputs exceed outputs, soil health
and tree roots are damaged. In addition, a number of
pathogens thrive under poor drainage conditions.
Drainage can be estimated by perculation tests.
Irrigation should be adjusted to the drainage class of
the soil, seasonal precipitation, and evaporation
demands. A $20,000.00 / 100 year old tree is
irreplaceable in three generations while the turf and
small shrubs are immediately replaceable at a modest
price. Priority must be given to high-value landscape
items like trees
(Figure 10).Figure 10.
Irrigation should be adjusted to the drainageclass of the soil, seasonal precipitation, and evaporation
demands. Priority must be given to high-value landscape
items like trees. Photo by Larry Korhnak
In the urban landscape the generation and
transportation of heat can have an impact on water
use in a tree and on a site. For every 18 degrees F
increase in temperature above 40 degrees F, site and
tree water evaporation and respiration almost double.
The more heat a site must dissipate, the more water
must be evaporated. Lack of evaporative surfaces
and few heat blocking or dissipating shade structures
allow heat accumulation on a site. Heat
accumulation "cooks" trees and soils present, while
heat moving onto the site from surrounding
hardscapes demands site water use for evaporation.
Irrigation must be tuned for handling additional heat
loads.
Chapter 7: Site Assessment and Soil Improvement 14
5. Aeration
Aeration is oxygen moving in large soil pores
from atmosphere to tree root surfaces. Soils have
combinations of aerobic and anaerobic sites and the
balance between them is constantly changing through
the seasons, days, or years. Oxygen movement can
only be assured by the presence of large pores,
fracture lines, decayed root lines, or aeration
columns. Compaction and flooding can produce
many water-filled pores. Oxygen moves 1,000 times
slower across a water barrier (water-filled pore) than
across a gas filled pore. Therefore wet or compacted
soils do not allow oxygen to effectively move to
roots. Any place where soil atmospheric oxygen
drops below 5% concentration, root growth stops.
As oxygen moves in the soil, many organisms
use its oxidation power before it reaches tree roots.
Under poor drainage and low oxygen conditions,
oxygen can be used up quickly. Once the oxygen is
consumed, soil organisms (not tree roots) begin to
use other elements for respiration. The respiration
sequence is oxygen, nitrogen, manganese, iron,
sulphur, and carbon. An entire year's fertilization
load of nitrogen can be respired away into inert
nitrogen gas within weeks under near anaerobic
conditions. Once the soil organisms start to respire
sulphur and carbon, many materials are formed that
will require purging or rinsing out of the soil for best
recovery. The warmer the temperature, the quicker
oxygen is consumed and the faster alternative
respiration will occur (i.e. doubling rate sequence for
respiration with increasing temperature).
Solutions for aeration problems are good
drainage and open soil surface for gas exchange. To
meet these goals, drain and sump systems can be
installed. These systems are made of perforated
pipes sunk to various depths. A drain system may
include a number of interconnected horizontal and
vertical pipes which were either pre-positioned
before planting or trenched-in afterwards. The goal
of a drainage system is to allow gravitational water
to move away from the soil and away from root
colonization areas. Sump systems use large diameter
perforated pipes vertically sunk into the ground well
beyond rooting depth to allow for accumulation of
gravitational water in the pipes. These water
containing pipes can then be pumped out
periodically. These pipes can also be used to quickly
saturate a soil area by filling with water during
droughts.
The other major form of aeration modification is
accomplished by terra-forming or sculpturing the
landscape. Designing berms, terraces, raised
mounds, and topography changes from grading
practices can all be used to gain root colonizable
space. These structures must be built to minimize
erosion and should be able to withstand a 100-year
rainstorm event.
6. Element Holding Capacity
Trees take-up essential elements in ionic forms
from soils. A small portion of the essential elements
are readily available, dissolved in tree-available
water. Most essential element ions are held near the
surfaces of clay and organic particles. Clays and
portions of organic materials (humus) have
negatively charged areas that attract and keep the
positively charged ions (cations) in close proximity.
These binding sites help keep essential elements
from being washed from the site. Cations include
calcium, manganese, zinc, magnesium, potassium,
and ammonium.
Cation exchange capacity (CEC) is a
measurement of the positive charged ion holding or
storage capacity of a soil. A calculation for rough
estimation of CEC is:
CEC = ((% organic matter in the soil) X 2.0) +
((% clay in soil ) X 0.5)
The formula suggests how effective additions of
clay and composted organic matter might be to a soil.
Organic matter is four times more effective for
improving CEC as clay. For soil type and texture,
relative CEC varies: sand =1; loam=5; silt loam=8;
clay=15. Cation exchange capacity generally
increases with soil pH.
Organic materials also have surface areas with
positive charges that attract negatively charged ions
(anions) like nitrate, phosphate, sulfate, chloride,
borate and molybdate. Anion exchange capacity
(AEC) is a small part of soil chemical activity.
Anions either move freely with water, like nitrates,
Chapter 7: Site Assessment and Soil Improvement 15
or are bound in insoluble forms like phosphates
(Figure 11)
.Figure 11.
Organic matter has many charged areas thatattract and conserve elements important for plant growth.
Photo by Larry Korhnak
7. Essential Elements
There are a number of elements essential to the
life and health of living things. Air (CO
2) and soilwater (H
2O) provide three essential elements (O, H,and C). Soil provides the remaining 15 essential
elements. An ecological system will progresses until
any one essential element or process becomes
limiting. It matters little how much nitrogen is added
to a site if zinc is the most limiting element to tree
growth. Below is
Table 4 which provides a generaland relative ratio of essential elements in trees.
Table 4.
Ratio of essential elements in trees. (* = fromCO
2
and H
2
O)
MACROS: MICROS:
hydrogen 60,000,000* chlorine 3,000
carbon 35,000,000* iron 2,000
oxygen 30,000,000* boron 2,000
manganese 1,000
nitrogen 1,000,000 zinc 300
potassium 250,000 copper 100
calcium 125,000 molybdenum 1
magnesium 80,000
phosphorus 60,000 Transformers
:sulfur 30,000 cobalt
nickel
On most terrestrial sites, nitrogen is usually
limiting for a number of reasons. Phosphorus can be
limited on wet and poorly drained soils. Fertilization
prescriptions should be nitrogen-centered but assure
easy phosphorus availability. Elements most often
limiting in order of importance are N, P, Mg, and K.
Excessive nitrogen fertilization has caused a number
of overdose events and over-medication programs to
damage ecosystems and trees, especially the very old
and the very young. Ecologically, both large doses
and no doses can be less productive and less healthy
than mid-ranges.
8. Organic Matter
Organic matter is once-living materials
decomposing and eroding back into the soil
(Figure12)
. As noted in the above discussions, organicmatter can improve soil structure, bulk density, water
and element holding capacities, and aeration.
Organic materials provide fuel, food and habitat for
the detritus engine of the soil. Urban forest soils
often have no or limited organic matter as well as the
associated flora and fauna which break-up and
decompose organic materials. Therefore the natural
processes of element cycling usually occur only in
small amounts on urban sites. Leaving fallen plant
materials on site and/or incorporating organic
admendments can greatly improve soil health and
in-turn the health of the urban forest.
9. Contamination
Soil is both easily polluted and difficult to clean
or restore. Contamination effects can out-right kill
and damage ecological and biological systems. In
addition, contamination acts to disrupt and poison
restoration processes
(Figure 13). General classes ofcontamination in soils are: lead and other heavy
metals (a legacy that does not decay); pesticides;
salt; petroleum products; biological excretions
(urine, feces, etc.); litter/construction materials; soil
Chapter 7: Site Assessment and Soil Improvement 16
Figure 12.
Organic matter is once-living materialsdecomposing and eroding back into the soil. Photo by
Larry Korhnak
crusting (hydrophobic surfaces from petroleum,
allelopathic materials, and organic coatings); and
buried trash from past construction and land-uses
(cement wash-outs, general land fills, garbage dump
(current or historic), poor coverage with top soil,
methane, and soil subsidence associated problems).
Figure 13.
Soil is easily polluted but difficult to clean orrestore. Soil contamination disrupts biological and
restoration processes. Photo by Larry Korhnak
Three examples of contamination which might
disrupt ecological restoration activities include:
1. Lead in soils from the days of leaded gasoline
(in Minneapolis, MN it was estimated that 2,000
tons per year of lead dust from autos fell on to
soil surfaces),
2. Animal and human wastes concentrate toxins
and salt content in fresh feces and urine. There
is also a risk of viral and bacterial disease with
contact of in-place soil or air-bourne soil, and
3. Floods wash down the contents of storage bins,
sheds and tanks from up-watershed to those
below, generating deposition and clean-up
problems.
Solutions to soil contamination problems begins
with identifying concerns and soil testing.
Associated with testing for contamination should be
development of a water and soil contamination map
of the site. Once this map is complete, a
prioritization system can be developed for other
treatments or activities. Contamination treatments
could include the complete removal or tie-up of
materials in the soil using pH, plasma jets,
organisms, chemicals, and /or barriers. Removal of
contaminated soil might fall under toxic waste
regulatory agencies to supervise. Mulching and
careful nitrogen fertilization across well-drained sites
can accelerate bacteria and soil processes which can
minimize or destroy some contaminants. Cultivation
or addition of a wetting agent might assist with
health restoration by breaking-up soil and organic
material crusts. Keep human contact away from
contaminated areas including collecting or
consumption of plant tissues, fruits, nuts, and
mushrooms.
10. Trophic Enrichment
Enrichment is the addition, infection,
contamination, or repatriation of the site with various
living things. A simple teaching model uses the term
"WAFBOM" which represents worms, arthropods,
fungi, bacteria, and organic material added to a site.
This multi-level trophic enrichment attempts to
restart the detritus ecological engine needed for soil
and tree health
(Figure 14). There remains a concernabout infecting sites with exotic organisms,
especially worms and fungi. Gene set trade-off must
sometimes be made in site restoration. Fully
conceived and operating processes, once established,
may eventually eliminate poor species or organisms.
Many urban sites for restoration are far removed
(islands) from sources of reintroductions and
infections of living things. If you build the perfect
restored system, species may find the site or not (if
you build it, they may not come). Active intervention
and infection at multiple trophic levels can accelerate
the site colonization process. Urban sites are tough
Chapter 7: Site Assessment and Soil Improvement 17
on beneficial organisms like arthropods, worms,
fungi and bacteria especially where increased heat
loads quickly "burn-out" organic matter in the soil.
Many sites could benefit from organism infection in
the nursery, or organism inoculum applied at
planting time.
Organic matter remains a universal resource for
restoration of urban forest sites. The organic matter
is the feed stock and habitat for beneficial soil
organisms and for tree roots. Composted organic
matter can be top-dressed over the site with a thin
protective layer of non-compressible, organic mulch
covering. Restoration managers are then placed in a
position of animal husbandry (microbe-jockeys).
Managers should beware of the wolves (pathogens
and exotic higher plants) among the sheep. Native
gene sets should always be conserved, but exotics
might help recover a site faster, serving as a nurse
crop or successional predecessor. Ecological and
genetic trade-off must always be made.
Figure 14.
Worms, arthropods, fungi, bacteria, andorganic material often need to be added to restoration
sites to restart the detritus ecological engine needed for
soil and tree health. Photo by Larry Korhnak
Conclusions
A key component in assessing sites for
ecological restoration is developing, both for your
own reference and others, a site picture, also called
determining the site context. Each site should be
assessed for its ecological context and societal
context. An ecological management unit (EMU), the
smallest treatable unit -- smallest restorable unit --
must be the focus for restoration management
activities. In addition to the ecological
considerations for a project, it is also important to the
success of any restoration project to include the
stake-holders, decision-makers and surrounding
social systems in all phases of the project. Site
assessment is a part of the planning and management
process, not a disjunct and separate piece. Remember
every site and situation will be different. An initial
site assessment should include inventory of
resources, space, size, diversity, temporal changes,
disturbances, stress, natural cycles, organic matter,
management, and a final action-list.
A restoration process includes an assessment of
present conditions, how they are changing, and
concentration of efforts on site factors which can be
repaired or improved -- soil health components.
Good soil management is essential for (and a part of)
healthy and sustainable ecological systems. Since a
number of soil features becomes degraded or
destroyed over time in highly stressed environments,
soil evaluation and improvement becomes
imperative. An average urban soil has few essential
elements, poor drainage, a compacted, heavy texture,
with little organic matter, low diversity and small
number of beneficial organisms. Restoration
activities need to be prescribed carefully in trophic
level order to assure success -- start at the bottom
and restore upward. The soil is the foundation upon
which we restore ecosystem functions and structures.
The soil attributes affecting and controlling soil
resources to be restored successfully include texture,
structure, bulk density, water, aeration, element
holding capacity, essential elements, organic matter,
contamination, and trophic enrichment.
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Chapter 8: Enriching and Managing Urban Forests for
Wildlife1
Joseph M. Schaefer
21. This is Chapter 8 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kämpf Binelli, and L.V. Korhnak, Eds.) produced
by the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Joseph M. Schaefer, Professor, Dept. of Wildlife Ecology and Conservation and Director, Center for Natural Resources, Cooperative Extension Service,
Institute of Food and Agricultural Sciences, University of Florida, PO Box 110230, Gainesville, FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Many positive outcomes result from enriching
and managing urban forests for wildlife. However,
effective management requires careful planning.
Baseline data on wildlife species that are currently
using the site should be collected prior to the
implementation of any plans. A site evaluation is
needed to determine what ecosystem components
need to be installed to improve the ecological value
of the property. Clear goals and objectives must be
established to effectively guide the process. Three
approaches to implementing a plan are managing
habitat, stocking species, and controlling negative
impacts of people and pets. Periodic monitoring of
species occurrence on the site will help to measure
success and will also indicate ways the plan should
be revised to obtain better results if necessary.
Introduction
The concept of accommodating both humans
and wildlife in the same area is nothing new.
Humans have always lived with other animals.
However, over geologic time, human populations
have increased and drastically extended their
dominance on the landscape. Many plant and animal
species that were once wild are now domestic.
Ecosystems that evolved through millennia of
natural processes and stochastic events have been
severely humanized within decades.
Many benefits can result from efforts to enrich
and manage wildlife in urban forests. Native animals
attracted to properly managed sites can provide
recreational and educational opportunities for local
residents (
Figure 1). People involved in planning,installing and using areas managed for wildlife
realize how decisions can directly influence
environmental quality and are likely to develop a
better land ethic. These areas also include the use of
native plants that require less water and nutrients
than exotic grasses and ornamental plants.
Developing a Plan for Wildlife
Effective wildlife management cannot be done
on just a whim. It requires careful planning. The
current condition of the site(s) needs to be
determined, and then a team of experts and
stakeholders should discuss and agree on what they
want to accomplish. An effective wildlife
management plan should contain base-line data, a site
evaluation, goals and objectives. For more
Chapter 8: Enriching and Managing Urban Forests for Wildlife 2
Figure 1.
Native animals attracted to properly managedsites can provide recreational and educational
opportunities for local residents. Photo by Larry Korhnak
information on developing plans for restoring the
urban forest ecosystem, see
Chapter 5 - Developinga Management Plan
.Base-line Data
Data on the current status of wildlife should be
collected before any other decisions are made. These
data will show which species are already present on
the project site(s). By comparing this list to a list of
species that have been documented to occur in the
same habitat types or ecosystems within the same
geographic range, you can identify those species that
could be accommodated. A team of experts can
determine the species or groups of species on which
the project should focus.
Small Snakes, Turtles, Lizards, Frogs,
Toads, Salamanders, Mice and Shrews
Acceptable scientific survey methods should be
used to collect these data. A drift-fence, pitfall trap
array is the best method to collect animals that crawl
or walk on the ground (for example: small snakes,
turtles, lizards, frogs, toads, salamanders, mice and
shrews)
(Figure 2). The materials needed for thisinclude a shovel, two 5-gallon plastic buckets with
lids, tin snips, and one 10-foot x 2-foot x 1-inch
board. In your project area, at least 5 yards from an
edge, dig a hole about 2-feet deep and 1-foot wide.
Make several holes in the bottom of the buckets by
drilling or hammering a nail or screwdriver. The
holes in the bottom will help rain water to drain out
of the bucket so caught animals will not drown. Place
one of the 5-gallon buckets in the hole so the top
edge is level with the ground surface. Cut a 1-inch
slit about 3 inches deep in the rim of the bucket with
tin snips. Dig a 10-foot long trench about 3 inches
deep out from the slit in the bucket. Lay the board
down next to the trench to determine where to dig a
hole for the second bucket (about 9.5 feet from the
first bucket). Dig a hole for the second bucket; cut a
slit in the rim; stand the board on its side in the
trench and in the slits in the two buckets; and backfill
dirt against both sides. You may need to support the
board in the middle with a stake or two. If your site
is large enough, you can use several bucket arrays
placed in different microhabitats (for example,
shaded and unshaded areas) so you can see if some
species have a preference for different areas. Shade
each bucket with the lid elevated at least 6 inches
above the ground to allow larger animals such as box
turtles to enter. Place a damp sponge in the bottom
on the buckets so captured animals will not dry out.
Collect these data for four consecutive days of each
season.
Figure 2.
A drift-fence, pitfall trap array is the best methodto collect animals that crawl or walk on the ground, such as
small snakes, turtles, lizards, frogs, toads, salamanders,
mice and shrews.
Larger Mammals
Larger mammals do not have to be caught to
record their presence. Raccoon, opossum, fox, and
others can be surveyed with tracking stations
(Figure 3)
. A tracking station consists of a bare soilarea (about 3-feet in diameter) covered with a layer
of dry Quickcrete (to better detect prints). In the
center, place a cotton ball immersed in oil or water
from a tuna fish can and placed on a stick pushed into
the ground. Check for tracks early each morning for
four consecutive days.
Chapter 8: Enriching and Managing Urban Forests for Wildlife 3
Figure 3.
Larger mammals such as raccoons can besurveyed with tracking stations. Photo by Larry Korhnak
Birds
A stationary count method is recommended to
most effectively detect birds in various layers of
vegetation
(Figure 4). Count stations should bepermanently marked outside and on a map to assure
reuse consistency. Select locations that will give you
the best chance of detecting birds on the site.
Usually, at least one station located about 50 feet
from the site will give you an opportunity to see birds
without scaring them away. Survey at this station
first. Then go into the site to survey at one or more
stations. Space your stations about 100 yards apart.
If your site is smaller, then use only one station.
Approach each station quietly. Wait one minute at
the station for the birds to get used to you before
counting. Record all birds seen or heard for the next
5 minutes. Count only those birds that appear to be
using the site, not those merely flying over it. Bird
counts should begin as close to sunrise as possible on
calm, clear mornings. Bird surveys should be
conducted four consecutive days of each season.
Figure 4.
A stationary count method is recommended tomost effectively detect birds in various layers of
vegetation. Photo by Larry Korhnak
Site Evaluation Checklist
A quick-and-easy instrument can be used to
assess the ecological value of a site. Wildlife
biologists have been using tools such as this
SiteEvaluation Checklist
(see Appendix 1 at the end ofthe chapter) for decades to estimate site suitability
for certain species. This particular Checklist is
designed to evaluate a site based on the occurrence
and diversity of important ecosystem components. It
helps to focus attention on the items that are missing
and how a manager can increase the ecological value
by installing them properly.
Goals and Objectives
The next step is setting clear goals and
objectives that will guide the process from beginning
to end (see also
Chapter 5 - Developing aManagement Plan
). Goals are broad statements thatgive a project general direction; objectives provide
specific destinations and time lines for different
aspects of the project. An example goal for wildlife
enrichment and management could be to enrich
wildlife within the Cincinnati park system. An
example of a specific objective would be to increase
the current number of native wildlife living in the
Cincinnati Zoological Park by 5 within the next 3
years. Progress toward achieving objectives can be
measured; progress toward goals cannot
(Figure 5).Implementing the Plan
There are three different approaches to
executing a plan to enrich and manage wildlife:
managing habitats; stocking species; and managing
people and pets. These approaches are not exclusive
of and can often complement each other.
Managing Habitats
A habitat is simply where an animal lives. It is
their address (
Figure 6). When using the termwildlife habitat, you must always refer to an animal
that lives or may potentially live there. And of
Chapter 8: Enriching and Managing Urban Forests for Wildlife 4
Figure 5.
An example goal for wildlife enrichment andmanagement could be to enrich wildlife in a park. Photo by
Larry Korhnak
course, the animal(s) would not be able to live there
if the area did not accommodate their survival needs.
To say that a particular piece of land is good wildlife
habitat is meaningless. You must say whether it is
good for black bear, pigeons, snakes or some other
animal or group(s) of animals. In other words, it is a
good place for them to live because it provides all of
the life-sustaining requirements for the species. To
manage a habitat is to make the place more or less
suitable for a particular species depending on whether
the goal is to increase or decrease numbers of the
species. The latter goal may be appropriate for
species that are involved in damage or nuisance
situations.
Figure 6.
A habitat is simply where an animal lives. It istheir address. Photo by Larry Korhnak
A natural ecosystem is a place where living and
non-living components interact in a condition that
has been relatively untouched by recent human
society. Living components include plants that fix
energy from the sun and manufacture food for the
other living components, animals. Non-living
components include soil, water, and minerals that are
important for the survival of plants and animals.
Ecosystems can be good or bad places (habitats) for
different species to live depending on whether or not
the ecosystem contains all of the components that the
species needs to survive. A tropical rainforest is a
very productive ecosystem, and provides good
habitats, or living conditions, for many species.
However, it is not good habitat for polar bears.
Many ecosystems in their existing condition do
not provide good habitats for species that once
thrived in them. As a result of human development
and land uses, many natural ecosystem components
are often destroyed and the interactions that made
them productive ecological systems no longer take
place. We can be good conservationists by putting
back or restoring as much of the original ecosystem
as possible. The theory behind improving habitat is
to build it and they will come.
Some sort of general knowledge of ecosystems
may be needed to help make this seemingly endless
task more feasible. Keep in mind that any living or
non-living component of a natural ecosystem
supports more natural ecosystem interactions than
asphalt and concrete. Even plant-free, sandy areas
may provide habitat to support a food chain
consisting of ants, ant-lions, and lizards. The
following are some ecological concepts that will help
you to be most effective in restoring an ecosystem.
The most fundamental concept that applies to
any ecosystem restoration effort is the more
diversity, the better. Restoration undertakings are
most cost efficient and ecologically effective when
the greatest diversity of ecosystem components is
provided. For example, $100 could purchase 5 holly
trees that will provide food for a variety of bird
species. Or, this same amount of money could
purchase one holly tree, an oak tree, a birdhouse,
some butterfly and hummingbird nectar plants, and
material to build a pond. These diverse ecosystem
components can provide not only berries for birds,
Chapter 8: Enriching and Managing Urban Forests for Wildlife 5
but also acorns for squirrels, nesting cover for
chickadees, nectar sources for dozens of butterfly
species and hummingbirds, and a place for eggs and
tadpoles of many frog species. This diversity
concept can also be applied to each type of
ecosystem component (e.g., trees, shrubs, perennials,
birdhouses, and water). For more information on
biodiversity, see
Chapter 3 - Biodiversity.Living and non-living ecosystem components
installed in urban areas help to restore the natural
value of sites making them better places for native
wildlife to live. In other words, management
practices that would include adding native
components would improve the habitats for many
native wildlife. These components provide some of
the essential requirements for animals: food, cover,
water, and space.
Food
Plants are the primary source of nutrients and
energy for animals. Some animals only eat plants
(herbivores or vegetarians); some eat plants and
other animals (omnivores), and some eat only meat
(carnivores). All of this eating, transfers energy and
nutrients to animals in the ecosystem's food web.
When animals eliminate some of the undigested food
or die, this nutrition is available for plants. This
cycle of life continues within the ecosystem as long
as there are sufficient food components (for more
information on nutrient cycle, see
Chapter 2 - BasicPrinciples
).Animals eat many plant parts. Squirrels eat
seeds, nuts, bark and buds. Insects eat leaves and
fruits. Birds eat nuts, seeds and fruits. Some of these
plant parts are only available at certain times of the
year. Buds are mostly available in the spring and
fruits and nuts in the fall. Adult cardinals eat mostly
seeds during winter, but eat insects when they are
feeding nestlings in the summer. Bluebirds eat
insects during summer, but include fruit in their
winter diet. If a site, does not have all of the foods
required at different times of the year, animals must
find food somewhere else and may leave the site
temporarily or permanently. Diets of each individual
(including humans) also change with age. Baby
humans consume different foods than adults. Baby
butterflies (caterpillars) eat leaves of specific plant
species while most adults eat flower nectar
(Figure7)
.Diversity in structure and species of plants is
much better than a large number of one species
(Figure 8)
. Food from some plants is most availableduring summer, others during the fall or some other
season. Variety provides food year-round. Some
animals nest close to the ground but feed on fruits or
insects of taller plants. Others nest in the highest
parts of the tallest trees and feed on or close to the
ground. A diversity of vertical vegetation layers will
provide suitable vertical habitat for the greatest
variety of animal species
(Figure 9).Figure 7.
Baby butterflies (caterpillars), such as this GulfFritillary caterpillar, eat leaves of specific plant species
while adults eat flower nectar. Photo (right) by Larry
Korhnak
Figure 8.
A diversity of vertical vegetation layers willprovide suitable vertical habitat for the greatest variety of
animal species.
Cover
Like humans, wildlife species need protection
from both predators and weather. Cover also helps
restrict the amount of food available at any time to
each level in a given food web so that the energy
flow will be sustained generation after generation.
For example, if bird nests were highly visible to
predators, every egg and nestling would be eaten and
Chapter 8: Enriching and Managing Urban Forests for Wildlife 6
Figure 9.
In developed areas vertical vegetation layersare often eliminated.
no offspring would be available to continue the
important balance between predators and prey.
Cover requirements are almost as diverse as
food requirements and can be provided by both plant
and non-plant ecosystem components. Some plants
are excellent fruit or nut producers, but their foliage
is not thick enough to offer good cover (for example,
dogwood trees). Dozens of birds, mammals, reptiles
and amphibians use tree cavities for nesting and
sleeping (birdhouses can help to artificially replace
this natural component). Many birdhouses of the
same size will accommodate only those birds of a
certain size, but a diverse selection of birdhouses can
provide nesting cover for birds as large as barred
owls and as small as chickadees
(Figure 10). Dozensof species use underground burrows for nesting,
sleeping and hiding.
Figure 10.
A Great-Crested Flycatcher finds cover in abirdhouse.
Water
Fresh water is essential for most plants and
wildlife. Many animals need to drink water and other
species such as frogs and toads require standing
water during all or some of the year to complete their
life cycles. A water source on one piece of property
may be critical to all wildlife living in the entire
neighborhood
(Figure 11).While traditional, elevated birdbaths are
accessible only to birds, a pond with gently sloping
sides allows many kinds of wildlife to choose
different depths to satisfy their requirements. Even
small depressions in rocks or soil that retain water
only temporarily help satisfy wildlife water
requirements. Some amphibians mostly use
temporary ponds that hold water only for a few
months out of the year.
Figure 11.
A fresh water source, such as this constructedpond, is essential for wildlife. Photo by Larry Korhnak
Chapter 8: Enriching and Managing Urban Forests for Wildlife 7
Space
An animal's need for space is simply the size of
an area containing sufficient food, cover, and water
for the creature to survive. This size varies
depending on the density and availability of these
resources. For example, a cougar (
Felis concolor)needs about 100 miles
2 (Nowak and Paradiso 1983)and an Eastern robin (
Turdus migratorius) needsabout 1/3 acre (Young 1951;
Figure 12).Most wildlife species are not able to satisfy their
space requirements on a typical urban site. Because
animals readily move across property lines, larger
suitable habitats can be accomplished if adjacent
properties containing suitable habitats are connected
to the project site.
As previously mentioned, most species have
vertical space requirements too. Some, such as the
American crow (
Corvus brachyrhynchos), nest highin tall trees but feed on the ground. Others, like the
hooded warbler (
Wilsonia citrina) and brownthrasher (
Toxostoma rufum), nest close to the groundbut feed in small trees.
Figure 12.
An animal's need for space is simply the size ofan area containing sufficient food, cover, and water for the
creature to survive. A robin needs about 1/3 acre. Photo
by Thomas G. Barnes
Other Habitat Concepts
Type of Ecosystem
Ecologists have developed a system of assigning
names to ecosystems according to their unique
natural characteristics. This also makes mapping,
management, and in some cases land use regulation
easier. Processes, interactions and components that
define ecological systems occur in patterns across
the landscape. Fire frequency is greater in prairie,
chaparral, and savannah sites than in riparian areas.
Areas with sandy/loamy soils are more suitable than
clay for burrowing animals such as gopher tortoises,
pocket gophers and ground squirrels.
Each ecosystem shares some characteristics with
adjacent ones, but is also very different from them.
For example, surface water flows downhill carrying
nutrients from upland to wetland sites. If a prairie
ecosystem is drastically altered during the process of
building a school facility, a highway, a house, or a
shopping center, all of the processes, interactions and
components unique to the prairie are also altered as
well as those in adjacent areas that were shared.
Replacing a prairie with temperate forest components
would not be the best way to restore the ecosystem
that was destroyed. Restoring the proper piece of the
landscape puzzle is the best way to improve the
ecology of the site so it interacts best with
surrounding areas
(Figure 13).Figure 13.
In a landscape, each ecosystem shares somecharacteristics with adjacent ones, but it is also very
different from them. Restoring the proper piece of the
landscape puzzle is the best way to improve the ecology of
the site so it interacts best with surrounding areas. Photo
by Hans Riekerk
Corridors
Many intact, relatively unaltered ecosystems
have been reduced in size or fragmented due to
various human development activities. These smaller
fragments often are not large enough to support
larger wildlife species. However, these fragments
can be connected with corridors that are ribbons of
Chapter 8: Enriching and Managing Urban Forests for Wildlife 8
suitable habitat for specific species connecting larger
habitat blocks. This connection effectively increases
the total size of the remnant ecosystem and its ability
to maintain sizable wildlife populations
(Figure 14).Genetic variation is maintained because genetic
material is carried freely through the corridor and
among large habitat blocks by dispersing wildlife.
Scattered animals also can use corridors to
recolonize areas that have suffered from local
extinctions. Corridor width is the most important
variable affecting its function. Wider strips are more
valuable than narrow ones. For more information on
corridors and ecological connectivity, see
Chapter 3- Biodiversity.
Figure 14.
Corridors may connect ecosystem fragmentsand provide suitable habitat for some species. Photo by
Henry Gholz
Edge Effects
One obvious characteristic of urban forests is the
sharp contrast between various land uses/vegetation
on these sites. Many human-made, sharp edges or
borders between vegetation types are found in this
type of landscape. These sharp edges cause many
problems for wildlife and their habitats.
Human-modified areas surrounding a forest fragment
are usually altered into earlier successional stages
(Figure 15)
.Figure 15.
Human-made sharp edges or borders betweenvegetation cause many problems for wildlife and their
habitat.
These areas are attractive to pioneering species
that invade several hundred meters into the adjacent
forest fragment and alter the plant species
composition and relative abundance which in turn
affects the suitability of the habitat for various
wildlife species. Along forest edges, avian brood
parasites (cowbirds), nest predators (small
mammals, grackles, jays, and crows), and non-native
nest hole competitors (e.g., starlings) are usually
abundant. Cowbirds feed in open areas and lays their
eggs in other species' nests found along forest edges.
Many birds cannot distinguish this foreign egg from
their own and devote all of their energy to raising the
young cowbirds. The eggs of the host species are
either removed by the adult cowbird or are pushed
out of the nest by the more aggressive cowbird
nestling. The result is cowbird numbers increase at
the expense of the host species
(Figure 16).A field-forest edge also attracts a variety of
open-nesting birds, but such an edge functions as an
"ecological trap." Birds nesting near the edge
usually have smaller clutches and are more subject to
higher rates of predation and cowbird parasitism than
those nesting in either adjoining habitats
(Brittingham and Temple 1983). A general principle
Chapter 8: Enriching and Managing Urban Forests for Wildlife 9
Figure 16.
Along forest edges, avian brood parasites areusually abundant; here a cowbird has laid its eggs in a
thrushs nest.
is that the greater the contrast between adjacent
vegetation types, the greater the edge effect.
Noise associated with construction, operation,
and maintenance of developments can cause harmful
impacts on wildlife. Animals that rely on their
hearing for courtship and mating behavior, prey
location, predator detection, homing, etc., will be
more threatened by increased noise than will species
that use other sensory modalities. However, due to
the complex interrelationships that exist among all
the organisms in an ecosystem, direct interference
with one species will indirectly affect many others.
Any forest tract has a "core area" that is
relatively immune to deleterious edge effects and is
always far smaller than the total area of the forest
(Figure 17)
. Relatively round forest tracts with smalledge-to-interior ratios would thus be more secure,
whereas thin, elongated forests (such as those along
unbuffered riparian strips) may have very little or no
core area and would be highly vulnerable to negative
edge effects.
Figure 17.
Any forest fragment has a core area relativelyunaltered by deleterious edge effects.
Edge effects have been shown to negatively
impact wildlife species within at least 300 feet of
forest boundaries (Janzen 1986, Wilcove et al. 1986).
Studies of nature reserve boundaries have provided
data that support the need for buffer zones of
decreasing use outside reserve boundary (Adams and
Dove 1989)
(Figure 18). The core of these areasmust be protected from cats, dogs, human activities,
noise, predators, exotic competitors, parasitism and
other detrimental effects of development.
Figure 18.
The core area of a fragmented forest may beprotected by the use of buffer zones.
Connection of Wetlands and Uplands
Wetlands are ecosystems that are periodically
inundated with water. They perform many functions
including flood control, water quality enhancement,
water supply, nutrient cycling, and good habitat for
many species (
Figures 19 and 20). Most species ofbirds, mammals, reptiles and amphibians feed or
breed in wetlands but also need access to surrounding
uplands to fulfill all of their life-sustaining
requirements. For example, aquatic turtles spend
most of their time feeding on plants and animals in
the water. However, one day each year, the female
must travel out of the water and find relatively sandy
upland soil to dig holes and lay eggs. Some of these
animals that move back and forth between wetland
Chapter 8: Enriching and Managing Urban Forests for Wildlife 10
and upland areas become food for upland animals,
adding both energy and organic matter to the upland
community. Surface runoff then carries some of the
organic material back into the wetlands. The
preservation or restoration of linkages between
uplands and wetlands is essential for preserving and
enhancing the structure and function of both systems.
Figure 19.
Most species of birds, mammals, reptiles andamphibians feed or breed in wetlands but also need
access to surrounding uplands to fulfill all of their
life-sustaining requirements. This wetland, for instance,
has no upland connection.
Figure 20.
This wetland has good upland connections,essential to most species of birds, mammals, reptiles and
amphibians to fulfill all of their life-sustaining requirements.
Stocking Species
Wildlife are stocked or transplanted in a number
of situations. Recovery plans for some species in
danger of becoming extinct include captive breeding
programs that include releasing the offspring into
suitable habitat areas. Game farms raise quail,
pheasant and other animals and release or stock them
in areas for hunters. Sometimes, animals living on a
proposed construction site may be removed and
transplanted to an area not slated for development.
Other stocking situations involve live-trapping
animals that are causing damage or nuisances and
releasing them in areas far away from the site of
infraction. The condition of the receiving habitat is
an important consideration in all cases. If the habitat
is evaluated as suitable, then you must answer the
question, why is the species not already present in
sufficient quantities?
The consequences of stocking species are
extremely complex. Many wildlife species can carry
dozens of diseases. Unless they are tested and found
to be disease free, introducing individuals into a new
area might enhance the spread of diseases
(Figure21)
. Also, new animals in an area can raise numbersabove carrying capacity (the number of animals that
can be supported by the areas resources).
Figure 21.
The consequences of stocking are extremelycomplex. Many wildlife species, such as this gopher
tortoise, might spread diseases if introduced to a new
area. Photo by Larry Korhnak
Managing People and Pets
Some wildlife adapt to increased human
activities in urban environments, but others do not.
Human-caused sounds, such as lawnmowers,
leaf-blowers, cars and trucks, and radios, may
interfere with important wildlife communications.
Many species are not tolerant of and will not live in
areas with high noise levels.
Education is the preferred method to manage
people. The goal of these educational programs
should be to change the behavior of people within
different target audiences so their activities are more
compatible with the wildlife management plans.
People who use the site or affect the site by their
Chapter 8: Enriching and Managing Urban Forests for Wildlife 11
activities need to understand the consequences of
their existing behavior and what they need to do to
become less damaging members of their ecosystem.
Predation and harassment of wildlife by
free-ranging domestic cats and dogs are other
challenges in urban ecosystems
(Figure 22).Figure 22.
Predation and harassment of wildlife byfree-ranging domestic cats and dogs are a challenge in
urban ecosystems. Photo by Larry Korhnak
Cats can be especially devastating to ground
feeding and ground breeding species. Hunting is a
feline instinct, and predation rates are not related to
hunger. One study reported that a single cat, which
regularly consumed domestic food, killed over 1,600
mammals and 60 birds in Michigan during an
18-month period (Bradt 1949). Domestic cat
predation has extirpated and endangered several bird
and mammal species and populations (Humphrey
and Barbour 1981; Gore and Schaefer 1993).
Another study concluded that domestic cats were
killing about 39 million birds in Wisconsin each year
(Coleman and Temple 1996).
Management of people and pets may include
restricting use of some areas where sensitive species
may live and educational programs informing people
of the detrimental impacts of free-ranging pets.
Monitoring and Evaluating
Changes in wildlife use of the site should be
monitored at least annually during the growing and
breeding seasons. Use the same methods that you did
for the baseline surveys. Winter surveys of
migratory species using the site are also
recommended. Continue to compare these data to
lists of species that have been documented to occur
in the same ecosystems within the same geographic
range. A chart comparing the number of wildlife
species found on the site (y-axis) with time (x-axis)
will illustrate the success of your project
(Figure 23).Figure 23.
Comparing the number of wildlife speciesfound in an area during several years will help illustrate
progress toward restoring wildlife.
Revising the Plan
Annual meetings should be held to discuss the
results of the surveys and other pertinent
information. If progress toward achieving stated
goals is satisfactory, continue as planned. If results
are not acceptable, decisions should be made for
revising the methods. Project managers also need to
be able to adapt to unexpected events, such as
damaging storms that may alter original management
plans
(Figure 24).Figure 24.
Annual meetings should be held to discuss theresults of the surveys and other pertinent information.
Photo by Larry Korhnak
Chapter 8: Enriching and Managing Urban Forests for Wildlife 12
Suggested Readings
Allison, J. 1991. Water in the Garden. Little
Brown & Co., New York, NY 10020.
Butts, D., J. Hinton, C. Watson, K. Langeland,
D. Hall, and M. Kane. 1991. Aquascaping: Planting
and Maintenance. Cooperative Extension Service
Circular 912, IFAS, University of Florida,
Gainesville, FL 32611.
Cerulean, S., C. Botha, and D. Legare. 1986.
Planting a Refuge for Wildlife. Florida Fish and
Wildlife Conservation Commission, Tallahassee, FL
32399.
Dennis, J. V. 1985. The Wildlife Gardener.
Alfred. A. Knopf, New York, NY 10022.
Martin, A. C., H. S. Zim, and A. L. Nelson.
1951. American Wildlife & Plants: A Guide to
Wildlife Food Habits. Dover Publications, Inc., New
York, NY 10022.
National Audubon Society Field Guide Series.
Publisher: Chanticleer Press, Inc., New York, NY
10012. Includes: Birds (Eastern Region), Birds
(Western Region), Butterflies, Mammals, Reptiles
and Amphibians, Trees (Eastern Region), Trees
(Western Region), Wildflowers (Eastern Region),
and Wildflowers (Western Region).
Ortho Books. 1988. Garden Pools & Fountains.
Ortho Books, Sanfrancisco, CA 94104.
Schaefer, J. and G. Tanner. 1998. Landscaping
for Floridas Wildlife: Re-creating Native Ecosystems
in Your Yard. University Press of Florida,
Gainesville, FL 32611.
The Golden Field Guide Series. Publisher:
Golden Press, c/o Western Publishing Company,
Racine, WI 53404. Includes: Birds of North
America, Trees of North America, Amphibians of
North America, and Reptiles of North America.
The Golden Nature Guide Series. Publisher:
Golden Press, c/o Western Publishing Company,
Racine, WI 53404. Includes: Golden Guide to Pond
Life, Golden Guide to Butterflies and Moths, Golden
Guide to Birds, Golden Guide to Trees, Golden
Guide to Reptiles, and Golden Guide to Mammals.
The Peterson Field Guide Series. Publisher:
Houghton Mifflin Company, Boston, MA 02116.
Includes: A Field Guide to Birds, A Field Guide to
Butterflies, A Field Guide to Mammals, A Field
Guide to Animal Tracks, A Field Guide to Bird
Nests, and A Field Guide to Reptiles and
Amphibians.
Xerxes Society. 1990. Butterfly Gardening.
Sierra Club Books, San Francisco, CA 94104.
Cited Literature
Adams, L. W. and L. E. Dove. 1989. Wildlife
reserves and corridors in the urban environment: a
guide to ecological landscape planning and resource
conservation. National Institute for Urban Wildlife,
Columbia, 91.
Bradt, G. W. 1949. Farm cat as a predator.
Michigan Conservation 18:23-25.
Brittingham, M. C. and S. A. Temple. 1983.
Have cowbirds caused forest songbirds to decline?
Bio Science 33:31-35.
Coleman, J. S. and S. A. Temple. 1993. On the
prowl. Wisconsin Natural Resources 20:4-8.
Gore, J. A. and T. L. Schaefer. 1993. Cats,
condominiums and conservation of the Santa Rosa
beach mouse. Abstracts of papers presented. Annual
Meeting of the Society for Conservation, Tucson.
Humphrey, S. R. and D. B. Barbour. 1981.
Status and habitat of three subspecies of Peromyscus
polionotus in Florida. Journal of Mammalogy
62:840-844.
Janzen, D. H. 1986. The eternal external threat.
Pages 286-303 in M. E. Soul. (ed.), Conservation
Biology: the science of scarcity and diversity.
Sinauer Associates, Sunderland, 584.
Nowak, R.M., Paradiso, J.L. 1983. Walker's
Mammals of the World. The Johns Hopkins
University Press, Baltimore, 1065-1066.
Wilcove, D. S., C. H. McLellan, and A. P.
Dobson. 1986. Habitat fragmentation in the
temperate zone. Pages 237-56 in M. E. Soule (ed.),
Chapter 8: Enriching and Managing Urban Forests for Wildlife 13
Conservation Biology: the science of scarcity and
diversity. Sinauer Associates, Sunderland, 584.
Young, H. 1951. Territorial behavior of the
Eastern Robin. Proceedings of the Linnaean Society
of New York 58-62: 1-37.
Chapter 8: Enriching and Managing Urban Forests for Wildlife 14
Appendix 1.
Site Evaluation Checklist -- This checklist can be used to determine the ecological value and site suitability forcertain species at any urban site.
COMPONENTS POINTS
FOOD COMPONENTS Point Values
1. Butterfly plants (Choose one from both nectar and larvae categories)
1 species of nectar plants 2 pts
2-5 species of recommended nectar plants 4 pts
> 5 species of recommended nectar plants 5 pts
Recommended larvae plants for 1 species of butterfly 3 pts
Recommended larvae plants for 2-5 species of butterfly 4 pts
Recommended larvae plants for > 5 species of butterfly 5 pts
Total (of maximum possible 10 pts) __ pts
2. Hummingbird plants (Choose one)
1 species of recommended nectar plants 2 pts
2-5 species of recommended nectar plants 5 pts
> 5 species of recommended nectar plants 10 pts
Total (of maximum possible 10 pts) __ pts
3. Native plants (Choose one from each of the 2 following groups)
1 species of recommended native plants 1 pt
2-5 species of recommended native plants 3 pts
> 5 species of recommended native plants 5 pts
Recommended plants from 1 category (grasses, grasslikes, herbaceous, vines, small
shrubs, tall shrubs, small trees, large trees)
1 pt
Recommended plants from 2-3 categories (grasses, grasslikes, herbaceous, vines,
small shrubs, tall shrubs, small trees, large trees)
3 pts
Recommended plants from >4 categories (grasses, grasslikes, herbaceous, vines,
small shrubs, tall shrubs, small trees, large trees)
5 pts
Total (of maximum possible 10 pts) __ pts
4. Bird feeders (Choose one)
1 feeder without black oil sunflower seeds 2 pts
1 feeder with black oil sunflower seeds 5 pts
Chapter 8: Enriching and Managing Urban Forests for Wildlife 15
Appendix 1.
Site Evaluation Checklist -- This checklist can be used to determine the ecological value and site suitability forcertain species at any urban site.
COMPONENTS POINTS
>1 feeder without black oil sunflower seeds 3 pts
>1 feeder with black oil sunflower seeds 10 pts
Total (of maximum possible 10 pts) __ pts
COVER COMPONENTS
1. Bird houses (Choose one; numbers of houses are for each half acre or half of a soccer field)
1 house of recommended specifications for 1 species 1 pt
2-3 houses of recommended specifications for 1 species 3 pts
>3 houses of recommended specifications for 1 species 4 pts
2-3 houses of recommended specifications for 2-3 species 6 pts
>3 houses of recommended specifications for 2-3 species 7 pts
>3 houses of recommended specifications for >3 species 10 pts
Total (of maximum possible 10 pts) __ pts
2. Treefrog houses (Choose one; numbers of houses are for each half acre)
1 house in appropriate location 3 pts
2-5 houses in appropriate locations 7 pts
>5 houses in appropriate locations 10 pts
Total (of maximum possible 10 pts) __ pts
3. Bat houses (Choose one)
1 house of recommended specifications and placement per half acre 5 pts
>1 house of recommended specifications and placement per half acre 10 pts
Total (of maximum possible 10 pts) __ pts
4. Vertical dead trees (Choose one; at least 1 foot in diameter and 10 feet high)
1 per acre 5 pts
2 per acre 7 pts
3 per acre 10 pts
Total (of maximum possible 10 pts) __ pts
5. Burrows (Choose one from each of the 3 following groups)
4 inch diameter opening 3 pts
> 4 inch diameter opening 4 pts
Chapter 8: Enriching and Managing Urban Forests for Wildlife 16
Appendix 1.
Site Evaluation Checklist -- This checklist can be used to determine the ecological value and site suitability forcertain species at any urban site.
COMPONENTS POINTS
Depth of 1-3 feet 3 pts
Depth > 3 feet 4 pts
Vegetation at least 1 foot tall within 1 foot of entrance 2 pts
Total (of maximum possible 10 pts) __ pts
6. Brush piles (Choose one)
1 brush pile 5 pts
> 1 brush piles 10 pts
Total (of maximum possible 10 pts) __ pts
7. Rock piles (Choose one)
1 rock pile 5 pts
> 1 rock piles 10 pts
Total (of maximum possible 10 pts) __ pts
WATER COMPONENTS
(Choose one only if it contains water for at least 1 month)Above ground bird bath(s) 2 pts
On ground, < 3 inches deep bird bath(s) 3 pts
Installed pond with steep sides and no areas < 3 inches deep 3 pts
Installed pond with sloping sides and some areas < 3 inches deep 4 pts
Installed pond with marsh or swamp plants from recommended list 5 pts
Installed pond with marsh or swamp plants from recommended list and connected to a
restored or natural upland area 6 pts
Natural body of water (pond, lake, stream, or river) with native marsh or swamp plants 8 pts
Natural body of water with native marsh or swamp plants and connected to a restored or
natural upland area
10 pts
Total (of maximum possible 10 pts) __ pts
SPACE COMPONENTS
1. Size of Site (Choose one)
Less than 1 acre 1 pts
1 to 5 acres 2 pts
5 to 10 acres 3 pts
Chapter 8: Enriching and Managing Urban Forests for Wildlife 17
Appendix 1.
Site Evaluation Checklist -- This checklist can be used to determine the ecological value and site suitability forcertain species at any urban site.
COMPONENTS POINTS
10 to 20 acres 4 pts
20 to 50 acres 5 pts
50 to 100 acres 6 pts
100 to 500 acres 7 pts
500 to 1000 acres 8 pts
1000 to 5000 acres 9 pts
more than 5000 acres 10 pts
Total (of maximum possible 10 pts) __ pts
2. Connected to > 1 acre of good habitats on adjacent properties
Yes 10 pts
Total (of maximum possible 10 pts) __ pts
3. Natural succession area
Natural succession area set aside as recommended 10 pts
Total (of maximum possible 10 pts) __ pts
4. Annually mowed area
Annually mowed area set aside and maintained as recommended 10 pts
Total (of maximum possible 10 pts) __ pts
Grand Total (of maximum possible 160 pts) __ pts
Chapter 9: Invasive Plants and the Restoration of the
Urban Forest Ecosystem1
Hallie Dozier
21. This is Chapter 9 in SW-140, "Restoring the Urban Forest Ecosystem", a CD-ROM (M.L. Duryea, E. Kampf Binelli, and L.V. Korhnak, Eds.) produced by
the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of
Florida. Publication date: June 2000. Please visit the EDIS Web site at http://edis.ifas.ufl.edu
2. Hallie Dozier, Forest Ecologist, 13213 Briar Hollow, Baton Rouge, LA 70810.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.
For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean.
Abstract
Many ornamental species spread from gardens
to natural areas where we do not welcome them.
These plants out of place, or weeds, threaten the
integrity of our natural systems. As gardeners we
demand access to thousands of exotic species,
unaware of side effects some have on natural
systems. The tale of public expectation of gardening
choice and variety began centuries ago. Early
colonists worried mostly about food security, but
from 1700 to the early 1900s Americans witnessed
extensive plant exploration and introductions.
Technological advances facilitated the change, as did
growing public interest in gardening and growing
prosperity found in nursery trade. Early colonists
introduced invaders such as Scotch broom and
common privet. Later explorers brought in other
ornamentals-turned-invaders including China-berry
and Norway maple. Welcoming non-native species
into our landscapes for centuries has created a
multi-billion dollar ornamental plant industry and a
gardening public that takes this largesse for granted,
selecting primarily on basis of color, shape, and size.
Today's public is unaware of the origins of most
ornamental plants and of the danger some species
pose to natural areas.
Introduction
Today conservationists are concerned about the
impacts invasive non-native plants have on our
natural landscapes. In North America, thousands of
non-native plant species succeed outside the confines
of cultivation (Randall and Marinelli 1996), that is,
they have naturalized. Most naturalized species are
not thought to harm or disrupt the ecosystems where
they are found, however, in roughly 300 cases,
naturalized plant species have had a demonstrably
negative effect in urban and rural natural areas - they
have become invasive (Marinelli 1996). Invasive
plant species can have direct impacts on natural
areas, when they form monocultures, exclude native
plants or change ecosystem functions. These changes
may, in turn, cause indirect changes to ecosystem
processes (c.f. Center et al. 1991; D'Antonio and
Vitousek 1992; Mooney and Drake 1986). Of the
recognized plant invaders introduced in North
America, deliberately and accidentally, over the last
500 years, roughly half were brought in for
ornamental purposes (Marinelli 1996). Species that
have become invasive include every plant form and
they vary in site requirements. They differ in degree
of aggressiveness; some take over soon after
introduction while others slowly build their
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 2
populations to a critical mass after which they
quickly expand into a full-blown invasion (Usher
1988). Spread may be cosmopolitan, affecting
similar ecosystems throughout a latitudinal band, or
spread may be somewhat limited in range. In North
America most invaders are terrestrial herbaceous
species, though many are woody (Center et al.
1991), and still others thrive in waterways (Nelson
and Richards 1994). Urban forest managers should
be concerned about biological invasions for two
reasons: 1) urban parks and natural areas may be
especially vulnerable to invasion because of high
levels of use (disturbance) and close proximity to
ornamental plantings; and 2) urban areas, with heavy
concentrations of ornamental plantings and
potentially heavily infested natural areas may serve
as jumping off points for invasion into natural
areas.
Although existing infestations remain to be
dealt with and pose managers considerable
challenges, it would be of tremendous benefit if the
movers of plant materials (e.g., landscapers and
home gardeners) were more discerning in selecting
the plant materials they put into the landscape. Many
people, however, even environmentally sympathetic
people and experienced gardeners, have little
information that would allow discerning plant
selection, such as knowledge of a plant's range of
origin or potential to be invasive (Colton and Alpert
1998; Dozier 1999). Moreover, though interested in
the topic, people generally are unaware of and do not
understand the issue of biological invasions, either
plant or animal (Colton and Alpert 1998). Among
gardeners and landscapers, though, the public
traditionally has been better informed. History
reveals that our knowledge of landscaping plants has
changed since the time when botanical introductions
were a topic of intense public interest and discussion.
Today, the variety of plants we have seems a matter
of course (see
History Section) to many gardenerswhose interest has shifted from the full story of the
plant and how it came to our shores to a more
functional interest, that is, how a particular plant
performs in terms of color, shape, texture and growth
potential
(Figure 1).We have, as gardeners, become accustomed to
having a tremendous variety of species from all over
the world at our disposal, and restricting ourselves to
using only native ornamental species would
eliminate nine in ten of our most common landscape
species (Van de Water 1995), that is, most of our
manipulated landscapes are comprised of non-native
species. When one of these species becomes
invasive we must ask ourselves what are the
ecological results of biological invasions? How
should we manage invaded sites? How can we
prevent future invasions? This chapter discusses the
ecology of plant invasions, some general approaches
to managing these invasions, and offers suggestions
for approaching education efforts regarding
invasions. Further, it briefly describes the history of
ornamental plants with particular attention to species
that have subsequently become invasive.
Figure 1.1
Ecology of Invasions
Definitions
It is important to define commonly used terms
before discussing plant invasions. They are:
Weed
- a plant out of place.Exotic
- not native to place where found.Typically we consider exotics to be those plants that
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 3
Figure 1.2
Figure 1.3
Figure 1.4
Figure 1.
Classic non-native landscape choices such asthis camellia (1.1), hydrangea (1.2), impatiens (1.3) and
lantana (1.4) give gardeners reliable lasting color and
interesting textures and shapes.
came to North America with Europeans after 1500
(FLEPPC 1999).
Colonizer
- species that enter unoccupied orsparsely occupied habitats, perhaps following major
disturbance.
Naturalize
- to establish as if native, to escapecultivation and successfully recruit to the next
generation.
Invader
- invasiveness has many definitions butthe common themes are ecosystem dominance,
displacement of native species and disruption of
system functions. Invaders are:
• Species that proliferate out of control and
degrade our ecosystems, make us ill or devour
our crops (Devine 1998);
• Species that have a significant effect on native
plants and animal; species that modify habitats
extensively or those that alter ecosystem
structure or rearrange the biology of a system on
a large scale (Mooney and Drake 1986);
• Species that can establish in relatively intact
sites and come to dominate or replace the native
flora (Bazzaz 1986); and
• Species whose introduction does or is likely to
cause economic or environmental harm or harm
to human health (Office of the President 1999).
Site Invasibility
For the most part, disturbed sites are thought to
be the most vulnerable to invasion. Disrupting
natural processes in a site puts it at risk for
aggressive species to enter the system, become
established, and supplant native species (Hobbs and
Huenneke 1992). Disturbance does not only imply
vegetation clearing or soil disturbance - altered
drainage patterns, fire suppression, waste dumps, and
storm water runoff filled with fertilizers or pesticides
- are all examples of disturbances (see
Chapter 4 -Disturbances and Succession
). Undisturbed sitesare rare, however, particularly in urban settings
where many invasions tend to occur in disturbed but
intact (eg., closed canopy) settings or along the
edges of such sites.
Site degradation is not the only factor
contributing to invasion: an area must be a suitable
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 4
site for the invader to succeed and there must be a
source of propagules (e.g., seeds, stems, etc.) for the
site to be compromised. In heavily landscaped urban
areas, propagules abound. Birds may deposit seeds
eaten from an invasive shrub, vine or tree in
neighboring yards, or bits of a plant may wash down
the stream after a heavy rainfall. A plant lover may
even opt to toss an unwanted plant into the wooded
lot behind the house because he or she cannot bear to
throw it on the trash heap. Depending on the species,
though, even a plant thrown on the trash heap may be
the starting point for an invasion.
Species invasiveness
Not all species are equally invasive, but invaders
often share several characteristics that give them the
advantage in a native ecosystem. They may be fast
growers, have high reproductive allocation (e.g.,
heavy flowering and fruiting), have easily dispersed
seeds and high germination rates, they may tolerate a
variety of site conditions, and they may be hard to
eradicate (Baker 1965). In other words, they are
easy to start and grow, and they are difficult to kill -
good landscape plants for urban gardens (Dozier
1999; Koller 1992).
One example of an ideal invader is the common
privet (
Ligustrum vulgare L.), one of the earliest(1500s) European arrivals in North America. In
addition to its landscape value, this multi-purpose
shrub served for dyeing, tanning, fiber, ink, and it
had medicinal applications (Haughton 1978). Until
the early 1800s it was the only privet grown in
America, but by the early 1900s this deciduous shrub,
susceptible to twig blight, had been replaced in
landscaping largely by Japanese privet (
L. japonicaL.)
(Figure 2) and Chinese privet (L. sinense Lour.)(Wyman 1969).
Figure 2.1 Photo by Charles Fryling
Figure 2.2 Photo by Charles Fryling
Figure 2.3 Photo by Charles Fryling
Figure 2.
Common ligustrum (2.1) was one of the earliestintroductions, brought in for its multiple uses. Together
with Chinese ligustrum (2.2) and Japanese ligustrum (2.3),
this genus has become extremely invasive in forests and
open areas across the country.
These are but three introduced privets in modern
nursery trade - where there is confusing mislabeling
among dozens of privets (Bender 1998; Brown 1945;
Odenwald and Turner 1987). Together, these three
species have become nuisance plants in natural areas
across the country from New England to Texas
(Randall and Marinelli 1996). The characteristics
that make privets the most commonly planted shrubs
in North America today translate into characteristics
that contribute to their invasiveness (
Table 1).Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 5
Table 1.
Landscape characteristics and invasiveness ofprivets.
Landscape Worthy
Characteristics
Invasive Characteristics
Propagates easily from
seeds and cuttings
Sexual and asexual
reproduction strategies
Long flowering period,
abundant flowers
High reproductive
allocation
Abundant flowers High reproductive
allocation
Flowers attract bees High reproductive
allocation
Abundant and
conspicuous fruit
display
Appealing to dispersers
Late summer to winter
fruit display
Appealing to dispersers
Attracts wildlife and
provides habitat
Appealing to dispersers
Prunes well Tolerates above ground
damage
Evergreen (except L.
vulgare)
Continuous growth
Thrives in sun or shade Generalist habit
Grows easily in any soil Generalist habit
Tolerates difficult
conditions
Generalist habit
Moderate to fast growth
rate
Outgrows slower growing
species
Ecological Impacts of Invasion
Not all invasions are created equal, but the speed
with which ecosystem changes occur when invasive
non-native species establish populations in natural
areas is alarming (Usher 1988). In severe cases,
invaders may form monocultures and completely
exclude native species, such as has occurred with
purple loosestrife in northern wetlands (Blossy 1996;
Mal et al. 1992; Mercer 1990). In cases where rare
plants are endangered, loss (from direct competition
with invaders) is a serious impact. Loss of rare
species is not the only impact of non-native plant
invasions, however. Plant invasions may also cause
ecosystem structure to shift from herbaceous to
woody, as when Chinese tallow tree invades
southeastern coastal areas (Bruce et al. 1995). In
other cases forests may be reduced to herbaceous
systems when vines, such as kudzu (
Pueraria logbata(Willd.) Ohwi) and English ivy (
Hedera helix L.)(Figure 3),
cover hectares of canopy trees (Bennett1993; Reichard 1996a) and prevent the next
generation of trees from establishing (see
Chapter 4- Disturbances and Succession
).Figure 3.1
Figure 3.2
Figure 3.
Invasive vines can smother mature forests,preventing recruitment of seedlings to adulthood. Most
kudzu (3.1) was brought in for erosion control in the
southeast, though it has also been used as an ornamental
species. English ivy (3.2), introduced before 1750, invades
mature forests in the Pacific Northwest and is easy to
propagate as a house or garden plant from rooted cuttings.
Conversions in vegetation due to invasion, in
turn, drastically alter ecosystem functions when they
change hydrologic, fire or nutrient cycles (Neil 1983;
Vitousek and Walker 1989; Whisenant 1990).
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 6
Changes in plant assemblage have another effect:
Plants are the starting point for all food webs - shifts
in plant community composition affect food quality
or availability, leading to changes, beneficial and
detrimental, to the health of dependent animal
populations. Invasive plants may grow so thickly
that small mammals, for example, are effectively
screened from overhead predators, leading to a shift
in their population which, in turn, causes other
changes in the system. When changes occur over a
short period of time, it may be too rapid for other
organisms in the system to adjust.
In the southwestern United States salt cedars
(
Tamarix spp.) have invaded riparian areas andchanged the composition and function of those
systems. The story of salt cedar is unique in that
managers have been working to control it for almost
half a century. This small tree was brought into the
United States early in the 19th century and used for
decoration and erosion control (Kennay 1996)
(Figure 4)
.Figure 4.1
Figure 4.2 Photo by Charles Fryling
Figure 4.3 Photo by Cotton Randal
Figure 4.
Salt cedars have plagued land managers forover 50 years (4.1). Originally introduced for ornament and
erosion control, these small trees have naturalized across
the country (4.2). In the southwest they invade riparian
zones and stabilize riverbed formation, crowd out native
plants, and lower water tables (4.3).
In the Rio Grande Valley conditions that
facilitated salt cedar invasion came about from
human manipulation of the river, including flow
diversion and livestock grazing. These activities, and
the ensuing environmental degradation, set the stage
for salt cedar domination of riparian vegetation
(Taylor and McDaniel 1998). Salt cedars stabilize
river sand bars and prevent natural channel
movement. They also induce degradation by tapping
into the water table and altering natural hydrology
(Muzika and Swearingen 1997)
Natural system structures may change when
invaders such as Chinese tallow tree (
Sapiumsebiferum
(L.) Roxb.) arrive (Figure 5). Tallow tree,introduced in the late 1700s, was brought here for the
practical applications it afforded - it provides an
excellent source of oil used for candle and soap
making, and it can provide shade under harsh
conditions, like those in a farm's chicken yard (hence
a regional name "chicken tree"). During the
expansion of the petroleum industrial complexes
near Houston, Texas during WWII, landscape experts
recommended this fast-growing tree to give quick
shade and reliable fall color to the new subdivisions
that sprang up near refineries (J. Griffith, Louisiana
State University, 1999, personal communication).
These refinery towns are located in the Gulf Coastal
Prairie - the remnants of which today are seriously
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 7
threatened by Chinese tallow invasion (NWRC
1999). Chinese tallow tree's impact in this area and
elsewhere has been to convert grasslands to forest, a
structural change that also affects function. For
example, natural fire regimes change because tallow
tree burns less easily than native grasses, it shades
out natives, and rapid breakdown of its leaves is
believed to alter soil solution composition,
contributing to faster eutrophication of wet systems
where it grows (Cameron and Spencer 1989). Its
leaves also release tannins which have a negative
impact on some invertebrate populations (Cameron
and LaPoint 1978). This species is not restricted to
wet sites, though, it also invades upland sites (F.
Lorenzo, Southern University, 1999, personal
communication). After centuries of cultivation and
improvement in its native Asia, this species is
essentially pest-free (Jubinsky 1995). Worse yet, it
also sprouts vigorously after cutting and is a prolific
seeder with high germination success, making
management extremely challenging.
Figure 5.1
Figure 5.2
Figure 5.
Chinese tallow tree (5.1) invasions convertgrasslands to forests, changing landscape structure and
shading out natives (5.2). It continues to be a popular
landscape plant in the southeast, due to its reliable,
brilliant fall color.
Management: Technical
How do we handle current invasions and how
can we prevent future invasions from occurring?
Managing invasions can be prohibitively expensive
(MacDonald and Wissel 1989; Taylor and McDaniel
1998), therefore managers must carefully decide
which invasions to tackle, weighing cost, feasibility
and likelihood of success. Using volunteers may
make management and control more practical when
otherwise it would be too costly (Bradley 1988).
Using a mixed approach that employs chemical and
mechanical methods may be the best means of
insuring long-term success (Dozier et al. 1998), but
to do so, it is helpful to understand some critical
aspects of the invasive species' life history (e.g.,
ability to coppice, reproductive strategies, response
to herbicides, etc.). Several volumes have been
published that are instructive to managers seeking to
control a variety of invasive species, including those
introduced for ornamental purposes (see
SuggestedReadings and Other Information
).Chemical Control
The key to long-term chemical management of
perennial weeds is to deliver a lethal dose of the
appropriate chemical to the underground tissues.
Translocatable herbicides follow the movement of
photosynthates, that is, sugars manufactured during
photosynthesis. It is essential, therefore, to time
herbicide application to coincide with movement of
photosynthates to storage organs so the herbicide is
transmitted to a plant's underground tissues.
Technical parameters determining management
success of invasive species include type of herbicide
used, strength, and number of applications. While
source/sink movement is the main physiological
parameter affecting chemical management success,
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 8
others include leaf developmental stage and point of
delivery. Careful consideration of environmental
conditions and an understanding how these
conditions affect physiological parameters of the
invader are also important for successful control
(Dozier et al. 1998). For example, some species may
require multiple applications to inhibit regrowth
from hard-to-kill underground tissues.
Developmental stage of an invader may
influence herbicide efficacy (Lee 1986; Willard
1988), and herbicide absorption may vary with
location of contact (Townson and Butler 1990).
Physiological responses to changing environmental
conditions can affect delivery of herbicide to
underground tissue in perennial invaders and
therefore influence management success. Seasonal
changes, for example, may have an impact on
control. Periods of low rainfall, and thus low
available soil moisture, may allow for greater
concentration of herbicide in underground tissues.
Also, late summer to early fall applications, when
carbohydrates are being shunted to storage tissues,
may increase translocation to underground tissues.
Mechanical Control
In some cases mechanical methods (cutting,
mowing, uprooting, burning, etc.) are effective for
controlling an invader. Mature plants may be cut
down or whole seedlings removed. For persistent
perennial species, though, one round of treatment
usually does not suffice, and repeated physical
removal may be required to free a site of an invader.
Usually such intensive management is not practical
or affordable, though biomass reduction will result
(Gaffney 1996; Willard 1988), aiding in the
short-term recovery of the treated site.
Norway maple (
Acer platanoides L.) (Figure 6)was introduced in 1762 (Wyman 1965), and since
has naturalized across the eastern region of the
United States.
Figure 6.1
Figure 6.2
Figure 6.
Norway maple successfully competes withnative maples due to greater allocation of resources to
foliar display (6.1). It is the most planted street tree in the
country, which may explain, in part, its spread in natural
areas across the nation, especially in the northeast (6.2).
One of the most commonly planted street trees
across North America, there are over 20 varieties
available in retail nurseries. Its ability to displace
native maples in natural areas may be linked to its
resource allocation to a heavy foliar display which, in
turn, enhances its shade tolerance and ability to shade
out understory vegetation (Niinemets 1998; Randall
and Marinelli 1996). The Norway Maple Removal
Experiment in the Drew University Forest Preserve
near Madison, New Jersey employs only mechanical
methods. In an effort to restore native ecology in the
forest preserve, volunteer students and faculty, and
paid grounds crews from Drew University used
machetes and chain saws to remove and girdle the
trees in January 1998. Thus far they have been able
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 9
to avoid using chemical control and are hoping that
natural regeneration will eliminate the need for
replanting native species. Ongoing monitoring
suggests that planting will be necessary to restore
native species, though large herbivores (e.g., deer)
will make replanting a special challenge.
Mechanical control alone may work best in the
early stages of invasion such as in the case of English
holly (
Ilex aquafolia L.) (Figure 7). This belovedholly of songs and holiday festivities was introduced
in the eastern United States prior to 1750, and in the
Pacific Northwest, in the 1860s (Lang et al. 1997;
Wyman 1969). In climates somewhat similar to its
native Mediterranean range, this small tree has since
naturalized in forested areas of California, Hawaii
and Oregon (USDA and NRCS 1997).
Conservationists concerned about English holly
populations developing in rare old-growth forests in
the northwest have incorporated its removal into
restoration projects that target other invasive species.
The city of Arcata, California is taking advantage of
existing restoration work in forest remnants to
remove shade tolerant English holly before the
problem gets out of hand (G. Ammerman, City of
Arcata, 1999, personal communication). With a
no-use chemical policy, all removal efforts are
manual - volunteer workers concentrate on hand
pulling young plants during Invasion Removal days.
Larger trees are rare, but each is hand dug carefully
to prevent excessive disturbance to the site. Given
the concern about protecting old-growth forests
(Reichard 1996b), Arcata's early intervention
approach to English holly is sensible, particularly in
light of the expense and difficulty managers face
when invasions expand rapidly or are ignored during
initial stages (Hiebert and Stubbendieck 1993; Hobbs
and Humphries 1995; MacDonald and Wissel 1989).
Figure 7.1
Figure 7.2
Figure 7.
English holly (7.1) has begun to show up in oldgrowth coastal forests (7.2) where managers remove
whole seedlings and carefully excavate mature plants.
Integrated management
Reliance on a single means of control may be
prohibitively expensive or result in failure for
aggressive species. A practical approach may be to
use mechanical control followed by chemical
application. For example, a woody species that
sprouts after cutting may be cut and herbicide
immediately painted onto all cut surfaces. A species
that responds to cutting by sprouting along the length
of its surface roots may be treated with herbicide
before
cutting or treated and left standing. Invasivespecies also may be mechanically treated, allowed to
grow new photosynthetic tissues, and then treated
with herbicides. The benefit of this approach is that
chemicals are applied to plants which have been
weakened by drains on carbohydrate reserves (starch
allocated to new shoot growth). Additionally,
herbicide application to the flush of new plant tissues
may maximize absorption and result in greater
efficacy.
Integrated management also includes replanting
the site with suitable species, for if the space freed by
removal of the invader is not filled with another
plant, the invader may return. After suppression of
the invader, the establishment of desirable plant
species is essential for long-term control of the site
(Dozier et al. 1998; Taylor and McDaniel 1998). The
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 10
strategy should be to replace the invader, not
temporarily remove it.
An example of such integrated management is a
salt cedar removal project in New Mexico. A variety
of methods have been used over the last half century
to control salt cedar, and researchers continue to look
for the combination of techniques that yields the best
result while lowering costs. Recent restoration
research in the Bosque del Apache National Wildlife
Refuge suggests that traditional clearing (mechanical
and chemical) followed by planting native
cottonwood and black willow poles can give
excellent results (Taylor and McDaniel 1998). In
addition to the integration of traditional control
methods, that is, removal of the invader and
replanting native vegetation, a new component has
been tried in these sites: timed irrigation is used to
contribute to natural regeneration of native species
while reducing salt cedar to a minor community
component. It appears that reactivating or
mimicking
natural water flow may prove essential tolong-term management of this species in riparian
systems.
Management: Social
Tastemakers
Educating the public about the benefits and
pleasures of gardening was the task of the 19th and
20th century tastemakers (see
History Section). Ourchallenge today is to inform people about
environmentally wise gardening as a means to
reducing biological invasions. History identifies the
groups who in the past have influenced the public to
become gardeners. They are the same as those who
are instrumental in landscaping trends today - garden
writers for popular publications
(Figure 8). For themodern media of television and radio, this group also
includes broadcast writers, producers and hosts. It
would benefit conservationists to recruit the efforts
of garden editors of top selling journals such as
Sunset Magazine
, Ladies' Home Journal, BetterHomes and Gardens
, and Southern Living, for each ofthese popular magazines reach millions of readers
(Wissenfeld 1998) and regularly influence people's
choices of landscape plants. If the tastemakers feel
concern about this issue they will undoubtedly add
this focus to their work. Opening lines of
communication between garden writers and
biological conservationists can only improve the
quality of information reaching gardeners.
Figure 8.
Many popular magazines feature gardeningarticles, which may promote invasive species. This 1994
article from Southern Living touts Chinese tallow for its
superior, early, and reliable fall color - a quality missing in
many native southern trees.
Landscapers, Horticulturalists, and Nursery
Owners
Customers rely heavily on nursery and garden
center personnel for gardening advice (Safley et al.
1993), however, nursery personnel are unable to
identify the native range of most of the plants they
sell, the majority of which are not native (Dozier
1999). If ornamental horticulture and landscape
design courses touched more on this topic, students
who go on to work in the nursery or landscaping
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 11
trades would be better equipped to understand this
issue. This, in turn, would have a positive effect on
how they conduct their businesses and how they pass
on information to their customers. People also turn to
their local Cooperative Extension agents for advice.
They too, could benefit from exposure to the subject
during their training.
Community Groups
Direct observation is a powerful tool in teaching
the public about non-native invasions. In a survey of
retail nursery customers (Dozier 1999), those
familiar with invasions were most likely to know
about the invasions as a result of personal experience
with the species or personal observation. Putting
restoration work in the public eye can be a means to
teaching people about invasions.
Today several projects across the country are
tackling non-native plant invasions, and many of the
restoration projects are in high traffic, high profile
parks and preserves. Highly visible projects,
particularly those that deal with landscaping
favorites, should include interpretive materials that
clearly outline the problem in that particular site, the
breadth of the problem in general, and the
importance of restoration activities and prevention.
These messages, however, are not always easy to
convey, and project organizers must take public
sensitivity and attachment to favorite plants into
consideration. Organizers of a Chinese tallow tree
replacement campaign in Gainesville, Florida,
learned hard lessons about public reaction to tree
removal - any tree removal (Putz et al. 1999). This
well planned campaign was supported by a variety of
critical stakeholders, including local nurseries,
government officials and educators, and it provided
educational components and incentives for home
gardeners. Despite these excellent efforts, though,
press coverage of the removal of a rather large
specimen on Arbor Day (a local newspaper ran a
color photo of one of the project planners next to the
tree, chainsaw in hand) sparked critical backlash
from the public. Thoughtful planning and careful
implementation are crucial to success, but they may
not garner desired results if public sentiment is
underestimated.
A project that had better public reception was a
miconia (
Miconia calvescens DC.) eradicationproject in Hawaii (Loope 1996; Mesureur 1996)
which employed (with considerable effort and
expense) television broadcasts, extensive press
releases, articles in major daily and weekly
publications, and distribution of hundreds of "most
wanted" posters. The efforts were so successful, in
fact, that citizens reported previously unknown
populations to authorities allowing them to
implement early control measures. The cost was high
in terms of effort, but it resulted in a public more
attuned to the issue of non-native plant invasions and
more vigilant about personal gardening practices.
Another way to teach these lessons is through
involving community members directly in restoration
work (Bradley 1988; Devine 1998). When
volunteers or other members of the public help
remove exotics and revegetate with natives, it gives
them the opportunity to have a real impact on their
(public) natural areas. It also gives managers the
opportunity to teach participants about wiser plant
selection for their personal gardens. The physically
challenging task of grubbing out small trees and
shrubs makes a lasting impression that may influence
a person's future choices in landscape plants.
Non-native plant invasions are going to occupy
land managers for years to come. The contribution to
this problem from urban areas, in the form of
ornamental species, is considerable, and urban
managers should pay special attention to addressing
this issue. Ornamental gardening history gives us a
glimpse of how modern fashions in landscaping
developed, and suggests how best to reach the
gardening public to reshape those tastes. The
gardening public, as well as those who work in
nurseries and as landscapers, clearly can be
instrumental in stemming introduction of invasive
species; managers should concentrate on
demonstrating to these groups - directly and through
gardening tastemakers - the damage invasions cause.
There are many opportunities for teaching people
about the issue of non-native plant invasions:
popular articles (including radio and television) on
gardening, highly visible restoration projects, and
education of resource people such as nursery
personnel, landscapers and extension agents. Just as
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 12
taking advantage of these opportunities enamored
the country with ornamental gardening (See
HistorySection
), these paths will allow us to develop into acountry of environmentally conscientious gardeners.
Wise Gardening Choices
What is the best educational message to give
those who decorate the urban landscape with
ornamental plants? It will not work simply to pass
out lists that inform people which plants are "bad."
While extremely useful, lists of invasive plants may
be difficult to compile and maintain - the lists
necessarily changing as scientists recognize more
invasions. Moreover, such lists may not indicate
exactly where a particular species is problematic
(FLEPPC 1995; FLEPPC 1999) which reduces the
list's usefulness. Nor will it work to teach people
simply to "plant natives" - most popular landscape
species are not native, and some natives can be as
aggressive and weedy, or as finicky, as non-natives.
Not only that, people may not respond well to a
simplistic approach that dictates what to plant and
what not to plant. Guilt over selecting a non-native
plant should not be a side effect of education.
A more feasible and beneficial course of action
is to teach people to gather as much information as
they can about the species they select. Learning
about landscape species gives gardeners interesting
information about the plants they use, and it will give
them the opportunity to make environmentally sound
choices in their gardening. In addition to asking for
information that will help them pick the right plant
for their landscape needs, gardeners can ask the
following:
1. What is this plant's native range?
2. How does the plant reproduce?
3. Is this a plant that needs a lot of
maintenance to keep it in check?
4. Is it an aggressive grower?
5. Does it attract birds?
6. Is it known to be invasive anywhere?
7. Is it known to be invasive in areas similar
to where I want to plant it?
Answering these questions will allow gardeners
and landscapers to have a better idea how their
choices may impact (if at all) areas outside of the site
they intend to change. This, in turn, should lead to
wiser choices on the part of gardeners and
landscapers.
History
Ornamental Plant Introduction
Our gardens are crowded with an amazing
wealth of exquisite plants both ornamental
and economic; our lawns are studded with
superb trees and shrubs satisfying in form,
color, flower, and often, fragrance; our
orchards bear fruit in such variety as to
lengthen their seasons far beyond those of
only a short time ago. Our annual crops of
garden catalogues are filled with long,
awesome lists, incredible illustrations, and
Baron Munchausen descriptions. As a result,
our minds are confused by numbers and
beauty and wearied by the labor of making
choices. Surely our notion of "bigger and
better" has run riot in gardens, their
catalogues and their books. Do we even
wonder or speculate as to how this has come
about? Or do we lazily accept the largesse?
-Ann Dorrance, 1945, p.73
Age of Function: Early Colonial
Spices and medicines derived from plants were
commodities important enough to drive the vast
world explorations conducted by 15th century
explorers (Dorrance 1945). Men and women who
settled in North America had little time for gardening
except that which was necessary to insure an
adequate supply of food, flavorings, medicines and
fiber. Naturally, they brought with them plants from
home including fruit trees and medicinal herbs
(Leighton 1986; Manks 1968; Martin 1988; van
Ravenswaay 1977; Wyman 1968)
(Figure 9).Some of the plants they brought were not native
to Europe, but adopted from other areas already
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 13
Figure 9.1
Figure 9.2
Figure 9.
Early settlers brought important medicinal andculinary herbs and food plants with them when they arrived
in North America. Tansy (9.1) has naturalized in several
states and is considered invasive in the Pacific Northwest
and elsewhere. Figs (9.2) have escaped plantations in
California's central valley to invade riparian zones (Randall
and Marinelli 1996).
explored; peaches, native to Asia, were brought here
by Spaniards in the 16th century (Crosby 1986;
Manks 1968)
(Figure 10).Figure 10.1 Photo by Larry Korhnak
Figure 10.2 Photo by Charles Fryling
Figure 10.
Peaches have been in cultivation for thousandsof years (10.1 and 10.2). Native to Asia, they first came to
North America with early Spanish explorers. Adopted by
native tribes, later European settlers initially believed
peaches native to the New World.
Well into the 17th century colonials had so little
leftover from their harvests that they relied, for the
most part, on Europe for most of their goods,
including each year's seed supplies, thus regular
intercontinental transport of plant materials began
early.
Some of the plants deliberately introduced
during the 16th and 17th centuries have naturalized;
a few are considered problem species in our
landscapes today. They include Scotch broom
(
Cytisus scoparius L.) (Figure 11) and commonprivet (Wyman 1968; Wyman 1969).
Age of Exploration: Eighteenth &
Nineteenth Centuries
Though colonists settling into their new
environment continued to be interested primarily in
gardening for function, the 18th century was a time
of great feats of plant exploration, export and
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 14
Figure 11.
Scotch broom was brought into the U.S. forpractical and ornamental purposes. Here the shrub
colonizes areas leveled by the 1992 fires near Berkeley,
CA. Photo by Susan Gabbard
introductions (Hedrick 1950; Manks 1968).
Botanists John Bartram and André Michaux, among
others, actively exchanged plant materials between
the world's continents, particularly North America,
Asia and Europe. Bartram, who became the
American botanist to King George III,
enthusiastically sent native American plants to
England in exchange for European and other species
that had performed well in Europe. Michaux also
helped populate European gardens with native North
American plants; during a ten-year period he sent
more than 60,000 live plants back to Europe
(Hedrick 1950; Manks 1968). His contributions to
North America include the China-berry tree (
Meliaazedarach
L.) (Figure 12), which came from Asiavia France, several popular species of azalea
(
Rhododendron spp.), and crape-myrtle(
Lagerstroemia indica L.), which he introduced tothe Charleston, South Carolina area (Hedrick 1950).
The work of these two men and their contemporaries
formed the basis of our current knowledge of North
American species, and we regard them as great
visionaries for their spirited investigation and
dissemination of American natives.
Figure 12.
An early introduction brought from Asia toNorth America by French botanical explorer, André
Michaux, Chinaberry tree has been used extensively as a
farm tree. Though many across the southeastern states
consider it a weed tree, it is also is useful for quick shade
and fuel wood (Haughton 1978). Photo by Charles Fryling
Commercial plant trade tended to de-emphasize
the value of native plants while promoting
non-native species. Robert Prince, who established
the first commercial nursery in Flushing, New York
in 1737, mostly promoted European novelties
(Manks 1968). An early advertisement from Prince
Nursery included dozens of species of apples and
stone fruits as well as ornamental species such as
silk-tree (
Albizia julibrissin Durazz.) (Figure 13),European Snowball (
Viburnum opulus L.), and treeof heaven (
Ailanthus altissima (Mill.) Swingle)(Figure 14)
(Hedrick 1950; McGourty 1968b).Figure 13.
Gardeners enjoy the mimosa, or silk tree, for itsshape, texture and fragrant pink blossoms. Introduced in
1745, this species since has become naturalized from New
York to California (USDA and NRCS 1997).
Notable introductions of the 18th century which
are with us today and which are, in some areas,
invasive, include English holly, Norway maple, a
troublesome species in northeast and northwest that
came in 1762, and English ivy (
Hedera helix L.),introduced in 1736 and now a major invader in
natural areas along the northern Pacific coast Randall
and Marinelli 1996; Wyman 1965; Wyman 1968).
Age of Adornment
By 1837 when Victoria ascended the British
throne, several events had occurred in the United
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 15
Figure 14.
Another early introduction (1784), the tree ofHeaven is valued in colder regions of the country for its
tropical-looking foliage and its ability to withstand harsh
urban conditions (Wyman 1968). In the southwest, it is
appreciated for its medicinal properties (Cheatham et al.
1995). Photo by Charles Fryling
States and abroad making way for the whirlwind of
horticultural activity that continued into the 20th
century. During the short span of 100 years, global
exploration increased, international trade became less
burdensome, the number, quality and availability of
printed materials increased, and industrialism
stimulated a prosperity that allowed the widespread
novelty of leisure time. These elements combined to
create a climate where pleasure gardening became
fashionable, accessible, affordable, and profitable.
Transportation, domestic and international,
improved dramatically during the early part of the
century. The opening of new post roads, the Erie
Canal (1825), and the Long Island Railroad (1836)
not only increased people's mobility, it facilitated
movement of gardening stock, especially by mail
order (Manks 1968). The historically famous
M'Mahon Nursery was just one of many eastern
sellers offering seeds and bulbs through the mail.
Early in the century, most plants were brought in
by botanical explorers, who commonly were
sponsored by wealthy patrons and botanical clubs.
With improvements in oceanic transit, world travel
became more common, and commercial nursery
owners interested in obtaining new or rare plants by a
faster route appealed directly to travelers to carry
home starting stock (Manks 1968).
Improved transatlantic travel had another impact
on gardening in the United States as well: one
upmanship. With increasing numbers of Americans
traveling to Europe and Europeans traveling to the
United States, a competition grew up between the
two continents, especially in the highly visible areas
of economy, social politics, and horticulture.
Europeans wrote prolifically about inferior American
landscapes and Americans shared with each other
impressions of beautiful and extensive European
gardens. According to 19th century horticulture
historian, Tovah Martin (1988), the situation for
Americans was not unlike Adam and Eve discovering
their nakedness, "The shame...was infinitely
confounded by the realization that the rest of the
world was clothed" (p. 51).
Newfound prosperity from industrialism
allowed Americans the leisure time to indulge in
horticulture as a pastime. This was especially true for
girls and women who used botanical pursuits as a
socially acceptable way to express themselves
intellectually and artistically (Martin 1988). Leisure
time also allowed for pleasure reading, and by the
1830s gardening magazines were common, including
those that featured articles describing tropical regions
of the world, where plant hunters busied themselves
collecting ever new and interesting specimens for
return to the United States. Authors wrote articles
specifically to educate and entertain a public eager
for sophistication and to encourage the American
public to become enamored with pleasure gardening.
These articles also served as a way to bring the exotic
world into the homes of everyday Americans.
Throughout the century, gardening advocates
inundated the press, garden clubs and speech circuits
with encouragement for fledgling gardeners (Martin
1988). They were the "tastemakers of the times
[who] saw their tasks primarily as a battle against
widespread ignorance," and thus, from the 1830s
onward, "Americans were subjected to an onslaught
of consciousness raising publicity aimed at educating
the masses about the pleasures of ornamental
gardening." To ensure that citizens did not forsake
these new pleasures and return to their traditionally
puritan ways, they were "continually coached by
vigilant gardening advocates" (p. 52).
Nursery owners joined others in promoting
pleasure gardening to an increasingly interested
public. A growing number of gardening journals
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 16
provided readers with detailed instruction on how to
plant and care for the variety of plants becoming
available across the country. Many of the guides
were written, edited, and published by large nurseries
and seed houses. Nurseries and seed houses also
frequently financed gardening books. With the
sponsorship of nursery and seed house owners,
Edward Sayers published three editions of
TheAmerican Flower Garden Companion
(1838). Suchpublications also served commercial nursery owners
as advertisements - most consumers preferred getting
their gardening advice from experts. One publisher
unfortunately promoted his book with claims of
objectivity, for he had no connection to any nursery,
and made such a poor impression that his magazine
failed in its first year (Hedrick 1950).
Over the century, the popular press continued to
bring the thrills and excitement of plant exploration
into American homes. The ongoing adventures of
botanical explorer Robert Fortune in China were
published, in serial form, in the influential
horticultural journal,
The Horticulturist and Journalof Rural Art and Rural Taste
(1846-1852), edited bypremier landscape architect, A.J. Downing. Other
publications provided subscribers with colorful
accounts of jungle treks in many far away places,
sometimes including detailed illustrations of exotic
queens and kings to captivate the American reader
(Martin 1988).
Independent horticulture societies (the first was
established in New York in 1818) began appearing in
addition to those that had branched from larger, older
agricultural societies formed during the previous
century (Hedrick 1950). These clubs, which
frequently relied on the support of wealthy,
horticulturally inclinded community leaders, began
to encourage nursery owners to import and develop
more and more ornamental specimens (Manks 1968).
In 1827, President John Adams made an official
request to foreign consuls to send seeds and
specimens of rare plants back to Washington for later
circulation, beginning a long period of
government-sanctioned plant introductions that
continues today (Wyman 1968).
Mid-century found America's obsession with
non-native plants widespread and unstoppable (van
Ravenswaay 1977). Lawns which had been
dominated by lush green were now neatly trimmed
with newly developed lawn mowers. Gardens
featured a variety of color from easily available,
tender (e.g., cold sensitive), tropical plants brought
to North America in Wardian Cases
(Figure 15) andraised in larger, improved glass houses
(Figure 16).Figure 15.
English botanist Nathaniel Bagshaw Ward (b.1791 d. 1868) found a way to defeat lethal salt water and
sea spray that commonly decimated entire live cargoes
when, in 1832, he successfully shipped live seedlings from
England to Australia in closed, glazed glass cases -
changing forever the business of plant import (Dorrance
1945).
Figure 16.1 Photo by Charles Fryling
The trend of using tropicals as bedding plants,
which clearly allowed for the continuous
introduction and sale of new plant material,
continues today
(Figure 17).Writers in the 1860s continued urging
Americans to adorn their estates with color and
bloom. Those who actively promoted gardening
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 17
Figure 16.2 Photo by Charles Fryling
Figure 16.
By the 1840s, glass making had improvedgreatly and manufacturing techniques for cast iron made it
possible to construct large, stable glasshouses for
growing every variety of plant. Pictured here, the Palm
House at Kew Botanical Garden in London (16.1) and the
interior of the Golden Gate Park Conservatory in San
Francisco (16.2).
Figure 17.
Nineteenth century gardeners began usingcold tender tropical plants as houseplants and as warm
season annuals, practices that continue today.
believed that most Americans could benefit from
expert help in order to develop their skills as
landscape designers. To ease the transition from
novice to experienced gardener, F.J. Scott addressed
the gardening needs of average families who lived on
small (~ 1/2 acre) suburban lots. This work appealed
to a large audience and helped "induce every family"
to explore the satisfaction of gardening and raptures
of tropical plants (Martin 1988). Private homes were
not the sole domain of horticulture. For a period of
several years, A.J. Downing used his journal to
supply a steady stream of editorials in which he
implored Americans to convince their local
governments to establish and fund public parks for
pleasure and recreation (Hedrick 1950). Due to his
efforts, those who did not own their own property
where they could enjoy the physical, psychological,
and moral benefits of gardening were able to enjoy
the new urban park systems designed and developed
by men like Frederick Law Olmstead, designer of
New York City's Central Park and Boston's Emerald
Necklace (Eisner 1994), and Thomas Meehan who
spearheaded the acquisition of lands for
Philadelphia's city parks (McGourty 1968a).
Gardening for pleasure became not only vogue, it
was on its way to becoming common, and the effect
on the plant trade was enormous. Scott's continued
bombardment of the American public with articles
promoting the knowledge of gardening and the
enjoyment of using tender tropical plants as annuals
perpetuated plant introduction in two ways: nurseries
had to scramble to provide customers with a constant
source of new plants from foreign places, and they
had to continue to stimulate the demand for new
plants. Plant hunters continued outbound with the
goal of introducing new and rare specimens to the
gardening public.
Following the Civil War, which temporarily
slowed horticultural progress, the opening of the
Arnold Arboretum in Boston (1872) renewed the
stimulus for introducing non-native plants,
particularly Asian flowering shrubs (Wyman 1968).
In the late 1890s the federal government established
the Office of Plant Introductions, which facilitated a
steady stream of plants into the country (Fairchild
1928).
Hundreds of foreign plant species came into
North America during the 1800s. Some have
naturalized and persist in modern landscapes,
including porcelain berry (
Ampelopsisbrevipedunculata
(Maxim.) Trautv.), salt cedar,Japanese honeysuckle, coral ardisia (
Ardisia crenataChapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 18
Sims.) and Chinese wisteria (
Wisteria sinensis(Sims.) Sweet)
(Figure 18) (Wyman 1969)Figure 18.1
Figure 18.2
Figure 18.3
Figure 18.
Both Chinese wisteria (18.1) and Japanesehoneysuckle (18.2) have long been known as aggressive
vines that escape cultivation in the eastern portion of the
United States. Almost 200 years after introduction (1804)
nandina (18.3) is making the jump from garden to natural
areas in northern Florida. Nevertheless, such old-time
ornamental species appeal to gardeners for their
fragrance, color and nostalgia (Dozier et al. In preparation).
Though the river of new plants introduced from
abroad slowed to a comparative trickle by the early
1900s, our affection for landscaping and ornamental
gardening did not. A new generation of plant
explorers grew up and horticulturalists refined the art
of breeding new varieties of well-loved species.
Botanical explorer, David Fairchild, under patronage
of Lathrop Barbour, introduced many species during
the first half of the 20th century (Fairchild 1938).
For over forty years, during most of which time he
worked as chief of the Seed and Plant Introduction
Section of the USDA (1898-1940), he collected
thousands of seeds and live plant specimens and
brought them into the United States. While Dr.
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 19
Fairchild considered the majority of species he
introduced useful (Fairchild 1928,:3-11), he usually
managed to procure several purely ornamental
species during any collection expedition (Wait 1968).
In 1918, Plant Quarantine 37 became law after
several damaging insects and diseases arrived with
new plants (Wyman 1968). While making certain
that new plants were free of insects or diseases
lowered the chances that pests harmful to economic
crops would enter the country, in some cases the
practice effectively freed new plants from their
natural controls and contributed to their invasiveness
(Jubinsky 1996; Randall 1996).
Horticultural activity slowed for most
Americans during the 1930s due to the Great
Depression, dampening nursery sales, but post-World
War II economic recovery in the late 1940s allowed
tremendous regrowth in this area. In the period
following the war, the garden center movement
developed, which, in turn, revolutionized the retail
plant industry (Schneider 1990). Homeowners soon
were able to buy directly from nurseries without
having to wait for mail order, and perhaps more
importantly, they were able to buy all their supplies -
tools, seeds, soil, fertilizer and pesticides - and obtain
gardening advice, in one convenient location.
The Twenty-First Century: So Greatly Does
Custom Prevail
Today countless images from daily newspapers,
magazines, books, films and television continue to
fuel our love for gardening. Enthusiasts can peruse
pages of colorful photographic layouts and articles
listing the multiple advantages of different plants, or
they can wander about any of over 400 beautifully
tended botanical gardens (B. Boom, New York
Botanical Garden, 1997, personal communication)
filled with flowering specialties from around the
globe
(Figure 19).Figure 19.
Botanical gardens perform many services,including educating the public about the world of plants. A
future path for botanical gardens and arboreta may be to
take a lead role in educating people about biological
invasions and the importance of preserving biodiversity.
Across the country, it is difficult to find a county
that does not have at least one plant nursery, there is
no postal route that does not carry seed and plant
catalogues into homes, and most bookstores feature a
whole class of gardening books. Most sizable towns
boast gardening/horticulture societies as well,
providing a venue for people to share their knowledge
and passion for plants. In the absence of nurseries,
large discount retail stores often have garden centers
attached, and in the absence of book retailers and
gardening clubs, gardeners can get information and
advice from the World Wide Web. In addition,
many television and radio stations broadcast
gardening shows. The efforts of book and journal
publishers, film, radio and television producers, and
garden patrons continue to provide huge rewards for
the nursery industry. The supply side of this well
developed supply/demand relationship represents a
minimum of $2.5 billion in annual wholesale trade
(potted flowering, foliage or house, and bedding
plants) (USDA 1996)
(Figure 20).Figure 20.1
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 20
Figure 20.2
Figure 20.
Landscape, house and annual plants are worthbillions of dollars in trade every year. Indian azaleas
(2031) and gardenias (20.2), both introduced species, are
well behaved in the landscape - staying exactly where the
gardener puts them.
Suggested Readings and Other
Information
Managers can find more information for
identifying and controlling specific weeds from a
variety of sources.
Books
Invasive Plants: Weeds of the Global Garden
-by John Randall (1996)
Identification and Biology of Non-native Plants
in Florida's Natural Areas
by Ken Langland andKathy Craddock Burks (1998)
The Southern Living Gardening Book
- by SteveBender (1994)
The Sunset National Garden Book
- by Lang etal. (1997)
Weed Handbook
available from the WyomingWeed and Pest Council
Private organizations and public agencies
California Exotic Pest Plant Council
(CalEPPC) at http://www.caleppc.org
Florida Exotic Pest Plant Council (FLEPPC) at
http://www.fleppc.org
Pacific Northwest Exotic Pest Plant Council
(PNW-EPPC) http://www.wnps.org/eppclet.html
Southeast Exotic Pest Plant Council (SE-EPPC)
at http://webriver.com/tn-eppc/
Tennessee Exotic Pest Plant Council
(TN-EPPC) at http://webriver.com/tn-eppc/
Bureau of Land Management - in western states
Cooperative Extension Services
USDA Animal and Plant Health Inspection
Service (APHIS) at
http://www.aphis.usda.gov/ppg/weeds/
weedhome.html
Weed Science Society of America (WSSA) at
http://www.wssa.net
Cited Literature
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origin of weeds. In
The genetics of colonizingspecies
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Bazzaz, F.A. 1986. Life history of colonizing
plants: some demographic, genetic, and physiological
features. In
Ecology of biological invasions of NorthAmerica and Hawaii
, edited by H. A. Mooney and J.A. Drake. Berlin, Germany: Springer-Verlag.
Bender, S., ed. 1998. The
Southern Livinggarden book
. Edited by F. Gilsenan. Birmingham,AL: Oxmoor House, Inc.
Bennett, H. 1993. Kudzu.
Georgia Forestry46:3-5.
Blossy, B. 1996.
Lythrum salicaria. In Invasiveplants: Weeds of the global garden
, edited by J.Randall and J. Marinelli. Brooklyn, NY: Brooklyn
Botanic Garden.
Chapter 9: Invasive Plants and the Restoration of the Urban Forest Ecosystem 21
Bradley, J. 1988. Bringing back the bush.
Sydney, Australia: Landsdowne Press.
Brown, C.A. 1945. Louisiana Trees and Shrubs.
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Louisiana Forestry Commission Bulletin No. 1.Baton Rouge, LA: Louisiana Forestry Commission.
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P.A. 1995. Initiation of a new woodland type on the
Texas coastal prairie by the Chinese tallow tree
(
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Effects of tannins on the decomposition of Chinese
tallow leaves by terrestrial and aquatic invertebrates.
Oecologia 32:349-366.
Cameron, G.N. and Spencer, S.R. 1989. Rapid
leaf decay and nutrient release in a Chinese tallow
forest.
Oecologia 80:222-228.Center, T.D., Doren, R.H., Hofstetter, R.L.,
Myers, R.L., and Whiteaker, L.D. 1991. Proceedings
of the symposium on exotic pest plants, Washington,
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Cheatham, S., Johnston, M.C., and Marshall, L.
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southern plains, and northern Mexico
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D'Antonio, C.M. and Vitousek, P.M. 1992.
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Brooklyn Botanic Garden.
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AN ORDINANCE OF THE CITY OF MANSFIELD
ESTABLISHING CRITERIA AND REGULATIONS FOR
THE PRESERVATION OF TREES; PROVIDING FOR
DEFINITIONS; PROVIDING FOR PERMIT
REQUIREMENTS; PROVIDING A REVIEW PROCESS;
PROVIDING FOR TREE PROTECTION AND
REPLACEMENT; PROVIDING FOR RESTRICTIONS ON
PRUNING AND PLANTING OF TREES; PROVIDING
ENFORCEMENT PROCEDURES; PROVIDING FOR THE
REPEAL OF ALL ORDINANCES IN CONFLICT;
PROVIDING A SEVERABILITY CLAUSE; PROVIDING
FOR PENALTY FOR VIOLATIONS HEREOF; AND
PROVIDING AN EFFECTIVE DATE.
WHEREAS,
the City of Mansfield, Texas, is a home rule City acting under its charteradopted by the electorate pursuant to Article XI, Section 5 of the Texas Constitution and Chapter
9 of the Local Government Code; and
WHEREAS,
trees are a valuable amenity to the urban environment and serve to creategreater human comfort by providing shade, cooling the air and otherwise tempering the effect of
summer heat, thereby reducing the requirements for air conditioning and the subsequent
depletion of scarce energy resources; and
WHEREAS,
trees purify the air by filtering pollutants and dust and release oxygen intothe air; and
WHEREAS
, trees provide natural habitat for many species of small animals; andWHEREAS,
trees protect land and structures by reducing run-off, binding soil andminimizing flood damage; and
WHEREAS,
trees are known to add dollar value to residential and commercial propertyand to increase income levels and tax revenues by attracting new business, industry and residents
through improving a city's image; and
WHEREAS,
the City of Mansfield desires to actively participate in the "Tree CityU.S.A." program and the "Keep Mansfield Beautiful", program; and
WHEREAS,
the City Council of the City of Mansfield has determined that treepreservation is necessary to adequately protect the public health, safety and welfare.
NOW, THEREFORE BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF
MANSFIELD, TEXAS:
That this ordinance shall be known as and may be referred to as the “Natural Resources
Management Ordinance.”
Ordinance No. ______
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D:\TREE PRESERVATION\PROPOSED ORDINANCE
NATURAL RESOURCES MANAGEMENT ORDINANCE
A. Purpose and Intent.
The purpose of this ordinance is to promote site planning which furthers the preservation of
mature trees and natural areas, to protect trees during construction; to facilitate site design
and construction which contribute to the long term viability of existing trees; and to control
the removal of trees when necessary. It is the further purpose of this ordinance to achieve the
following broader objectives:
·
Prohibit the indiscriminate clearing of property.·
Protect and increase the value of residential and commercial properties within the City.·
Maintain and enhance a positive image for the attraction of new business enterprises tothe City.
·
Protect healthy quality trees and promote the natural ecological environmental andaesthetic qualities of the City.
B. Definitions.
For the purpose of this ordinance, certain words or terms applicable hereto are defined as
hereinafter provided. Words and terms used in this ordinance, but not defined in this
ordinance shall have the meanings ascribed thereto in the Zoning Ordinance or other
ordinances of the City. Words and terms defined in two ordinances shall be read in harmony
unless there exists an irreconcilable conflict in which case the definition contained in this
ordinance shall control. Words used in the present tense shall include the future, words used
in the singular number shall include the plural number and words used in the plural shall
include the singular. The word "shall" is mandatory and the word "may" is permissive. The
word “City” means the City of Mansfield, Texas.
Agricultural Use
: The use of land to produce plant or animal products, such as the growingof crops, raising and pasturing of livestock, or farming. It does not include the processing of
plant or animal products after harvesting or the production of timber or forest products.
Buildable Area
: That portion of a building site exclusive of the required yard areas on whicha structure or building improvements may be erected and including the actual structure,
driveway, parking lot, pool and other construction as shown on a site plan.
Building Pad
: The actual foundation area of a building and the area within six feet (6’) of thefoundation that is used for construction and grade transition.
Clear-Cutting
: The removal of all of the trees or a significant majority of the trees within anarea.
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Critical Root Zone (CRZ)
: The area of undisturbed natural soil around a tree defined by aconcentric circle with a radius equal to the distance from the trunk to the outermost portion of
the dripline. (See Appendix A.)
Cut/Fill
: Areas where the natural ground level has been excavated (cut) or fill brought in.Drip Line
: A vertical line run through the outermost portion of the canopy of a tree andextending to the ground. (See Appendix A.)
Limits Of Construction
: A delineation on the graphic exhibit which shows the boundary ofthe area within which all construction activity will occur.
Municipal/Public Domain Property
: Examples of this would include City Hall, public parks,County property, Corps of Engineers property, State of Texas R.O.W., library, fire stations,
water tower sites or similar properties.
Protective Fencing
: Chain link fence, wire fence, orange vinyl construction fencing, snowfencing or other similar fencing with a four foot (4') approximate height.
Selective Thinning
: The removal of selected trees from within a densely forested area.Tree
: Any self-supporting woody perennial plant which will attain a trunk diameter of twoinches (2") or more when measured at a point four and one-half feet (4.5’) above ground
level and normally an overall height of at least fifteen feet (15’) at maturity, usually with one
(1) main stem or trunk and many branches. It may appear to have several stems or trunks as
in several varieties of oaks.
Tree Board
: There is hereby created and established a City Tree Board. This Board shall bethe Planning and Zoning Commission unless otherwise appointed by City Council.
Tree, Marginal
: A tree which the City has determined may or may not be worthy ofpreservation depending on the individual characteristics of the tree. (See Appendix C.)
Tree, Park
: Trees in public parks and all areas owned by the City to which the public has freeaccess to as a park.
Tree, Protected
: A quality tree that has a diameter of six inches (6”) or greater; an understorytree that has a diameter of two inches (2”) or greater; and a marginal tree that has a diameter
of six inches (6”) or greater that the Landscape Administrator has determined should be
saved due to individual characteristics and/or location of the tree. The diameter of a tree
shall be determined by measuring at four and one-half feet (4.5’) above ground. For a multitrunk
tree, the diameter shall be the total diameter of the largest trunk plus half (½) the
diameter of each additional trunk.
Tree, Quality
: A tree which the City has determined typically has significant positivecharacteristics worthy of preservation. (See Appendix C.)
Ordinance No. ______
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Tree, Street
: Trees on land lying between property lines on either side of all streets, alleys,avenues, lanes or ways within the City.
Tree Topping
: The severe cutting back of limbs to stubs larger than three inches in diameterwithin the tree’s crown to such a degree so as to remove the normal canopy and disfigure the
tree.
Tree, Understory
: A tree which the City has determined has significant positivecharacteristics worthy of preservation and that does not typically attain great size. (See
Appendix C.)
C. General Provisions.
1. Clear-cutting: The clear-cutting of land as defined in this ordinance is prohibited.
2. Selective Thinning: The removal of selected trees from within a densely forested area
when done in a professionally accepted manner shall be allowed as a single permit upon
approval by the Landscape Administrator. Approval will only be granted when the
Landscape Administrator determines that the selective thinning is being done in a manner
that would enhance the environment and likelihood of survival for the remaining trees.
3. Ground Level Cuts: Where protected tree removal is allowed through exemption or by
tree removal permit and the root system is intertwined with protected trees which are
intended to be saved, the tree shall be removed by flush cutting with the natural level of
the surrounding ground. Where stump removal is also desired, stump grinding shall be
allowed, or upon approval of the Landscape Administrator, a trench may be cut between
the two trees sufficient to cut the roots near the tree to be removed, thereby allowing
removal of the remaining stump without destruction of the root system of the saved tree.
D. Tree Removal Permit Required.
No person, directly or indirectly, shall cut down, destroy, remove or move, or effectively
destroy through damaging, any protected tree situated on property regulated by this
ordinance without first obtaining a tree removal permit unless otherwise specified in this
ordinance.
E. New Developments.
All developments which have not submitted final construction plans as of the effective date
of this ordinance shall be subject to the requirements for tree protection and replacement
specified herein.
1. Residential Developments: All area within street right-of-ways, utility or drainage
easements as shown on an approved final plat and area designated as cut/fill on the
master construction plan approved by the Landscape Administrator shall be exempt from
the tree protection and replacement requirements specified herein. The developer may
request the Landscape Administrator to allow trees within potential building pad areas be
Ordinance No. ______
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D:\TREE PRESERVATION\PROPOSED ORDINANCE
included in the exemption described herein. All other area shall be subject to these
requirements.
2. Non-residential Development: All area within street right-of-ways, utility or drainage
easements as shown on an approved final plat, area designated as cut/fill on the master
construction plan approved by the Landscape Administrator, plus fire lanes, parking areas
and building pad as shown on an approved site plan shall be exempt from the tree
protection and replacement requirements specified herein.
3. Permit Requirements: A tree-removal permit shall not be required for removal of a
protected tree within an area noted in Sections E.1 and E.2 above, however a permit must
be obtained prior to the removal of any other protected tree on the property.
4. Landscape Administrator Review:
a. Residential Development: A developer shall be required to furnish a transparency of
the proposed development showing all proposed improvements (e.g. right-of-ways,
easements, lot patterns, cut/fill, etc.) with the submittal of a site plan, development
plan, preliminary plat, or final plat, whichever occurs first. The transparency shall be
on a sheet drawn to the scale of one inch equal to one hundred feet (1”:100’) or on a
computer disk in the format of a commonly used Computer-Aided Design (CAD)
program. The Landscape Administrator is authorized to require a tree survey meeting
the requirements of Appendix D herein when determined to be needed to fully
evaluate the impact on trees.
b. Non-Residential Development: A developer shall be required to furnish a
transparency of the proposed development showing all proposed improvements (e.g.
right-of-ways, easements, lot patterns, cut/fill, fire lanes, parking areas and building
pads, etc.) with the submittal of a site plan, development plan, construction plan, plot
plan or building permit application, whichever occurs first. The transparency shall be
on a sheet drawn to a scale as required by the Landscape Administrator and in a
format depicted in Section E.4.a above. The Landscape Administrator is authorized
to require a tree survey meeting the requirements of Appendix D herein when
determined to be needed to fully evaluate the impact on trees.
c. It is highly recommended that the developer consult with the Landscape
Administrator and submit the required transparency or survey for review as early as
possible so as to minimize changes in preliminary or final plats and to determine that
there is adequate area for the proposed improvements after tree protection and
replacement have been taken into consideration.
d. The Landscape Administrator will evaluate the required transparency, survey or plan
to determine that the developer has made a best good-faith effort at saving as many
protected trees as possible. The Administrator will forward review comments to the
Planning and Zoning Commission for consideration regarding denial or approval of
the development. If the review involves a document that normally does not require
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the approval of the Planning & Zoning Commission, the Administrator will follow
the procedures in Section I herein.
5. Parking Area: When a non-residential development consists of extra parking spaces
beyond 110% of the minimum parking spaces required by the Zoning Ordinance, the
developer shall be required to replace a percentage of the trees removed or make a
payment into the Tree Restoration Fund. The replacement trees shall be calculated by
multiplying the total diameter of trees removed in all parking spaces by the percentage of
said extra parking spaces to the total number of parking spaces (i.e. total diameter of trees
removed
x extra parking spaces ÷ total parking spaces). The replacement trees shall beprovided in accordance with Section J herein.
F. Private Property.
1. Homestead: The owner of property which is used for an individual residence or
homestead shall be exempt from the tree protection and replacement requirements
specified herein.
2. Property Owned by Home Builder: All area within the building pad, driveway, sidewalks,
patios, septic tank and lateral lines, parking area, pool and associated deck area as shown
on a plot plan approved by the Landscape Administrator shall be exempt from the tree
protection and replacement requirements specified herein. All other area of the lot shall
be subject to these requirements.
a. Permit Requirements: A tree-removal permit shall not be required for removal of a
protected tree within an area noted above, however a permit must be obtained prior to
the removal of any other protected tree on the property.
b. Landscape Administrator Review: A transparency showing all proposed
improvements shall be required with the submittal of building permit application.
The transparency shall be on a sheet drawn to a scale as required by the Landscape
Administrator or on a computer disk in the format of a commonly used Computer-
Aided Design (CAD) program. The Landscape Administrator is authorized to require
a tree survey meeting the requirements of Appendix D herein when determined to be
needed to fully evaluate the impact on trees.
3. Agricultural Property: The owner of property being actively used for agricultural
purposes shall be permitted to remove up to seven (7) protected trees per calendar year
without obtaining a permit. Protected trees removed in excess of seven will require
permits. It is not the intent of this ordinance to prohibit the clearing of land for
legitimate, agricultural use. The property owner shall request the Landscape
Administrator to make an on-site inspection of the property to be cleared and provide the
Landscape Administrator the purpose and reason for the clearing. If the Landscape
Administrator determines the clearing of land to be for a legitimate, agricultural reason,
he will issue a tree removal permit.
G. Municipal/Public Domain Property, Right-of-ways and Easements.
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All construction and maintenance activities within municipal/public domain property, rightof-
ways or easements by the City, franchise utility companies or other entities shall be
subject to the requirements for tree protection and replacement specified herein.
1. A tree removal permit shall not be required for removal of a protected tree. However no
construction or maintenance activity that may cause the removal of a protected tree shall
begin until construction plans showing protected trees to be removed and the location of
replacement trees have been approved by the Landscape Administrator. Pruning
activities by a utility shall be governed by the provisions of Section M.
2. Tree Board Responsibilities: It shall be the responsibility of the Tree Board to study,
investigate, counsel and develop and/or update periodically, and administer a written plan
for the care, preservation, pruning, planting, replanting, removal or disposition of trees in
parks, along streets and in other public areas. Such plan shall be presented to the
Council, and when adopted, shall represent the comprehensive tree plan for the City.
3. Acceptable Trees: The Landscape Administrator shall maintain a list of trees acceptable
for planting along streets, within parks or other public areas. Trees other than those listed
as acceptable may only be planted upon approval of the Landscape Administrator.
4. Street Tree Spacing: The spacing of street trees shall be in accordance with
recommendations of the Landscape Administrator. Closer spacings or group plantings
may be approved by the Landscape Administrator in unique situations and when
recommended by a registered Landscape Architect.
5. Public Tree Care: The City shall have the right to plant, prune, and maintain street trees
and park trees within the lines of all streets, alleys, avenues, lanes, squares, and public
grounds, as may be necessary to insure public safety or to preserve or enhance the
symmetry and beauty of such public properties. The City may remove or cause or order
to be removed any tree or part thereof, which is in an unsafe condition, or which by
reason of its nature is injurious to sewers, electric power lines, gas lines, water lines or
other public improvements, or which is affected with any injurious fungus, insect or other
pest.
H. Exceptions
A tree removal permit and tree protection and replacement requirements shall not be required
under any of the following circumstances. The burden of proof as a qualified exemption is
upon the remover of a tree. It is highly recommended that qualification as an exemption be
determined with the Landscape Administrator prior to removal of any tree.
1. All construction activities for which final construction plans and building permit
applications have been submitted prior to the effective date of this ordinance shall be
exempt.
2. Diseased Trees: The tree is diseased, damaged beyond the point of recovery, or in danger
of falling as determined by the Landscape Administrator prior to the removal of the tree.
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The removal of a diseased tree by the City or an individual is required to reduce the
chance of spreading the disease to adjacent healthy trees.
3. Public Safety: The tree endangers the public health, welfare or safety and immediate
removal is required.
4. Utility Service Interruption: The tree has disrupted a public utility service due to a
tornado, storm, flood or other act of God. Removal shall be limited to the portion of the
tree reasonably necessary to reestablish and maintain reliable utility service.
5. Landscape Nursery: All licensed plant or tree nurseries shall be exempt from the
requirements of this ordinance as they pertain to those trees planted and growing on the
premises of said licensee that are so planted and growing for the sale or intended sale to
the general public in the ordinary course of said licensee's business.
I. Permit Review and Approval Process.
1. Authority for Review: The Landscape Administrator shall be responsible for the review
and approval of all requests for tree removal permits submitted in accordance with the
requirements specified herein.
a. Deferrals: The Landscape Administrator may defer the approval of a tree removal
permit to the Tree Board for any reason. All decisions made by the Tree Board shall
be final.
b. Appeals: Any decision made by the Landscape Administrator may be appealed to the
Tree Board. All decisions made by the Tree Board shall be final.
2. Submittal Requirements: The Landscape Administrator shall establish administrative
procedures necessary to facilitate the implementation and enforcement of this ordinance.
a. Tree Removal Permit: A request for a tree removal permit must be submitted and
approved prior to the removal of any protected tree in the City unless the tree is
exempt under a provision of this ordinance.
b. Fees: All tree removal permits shall be accompanied by a payment made to the City
in the amount specified by City Council.
c. Required Documents: Either a transparency or tree survey shall be required as
determined by the Landscape Administrator and must include the items referenced in
this ordinance and its appendices.
d. Permit Expiration: Permits for tree removal issued in connection with a building
permit or site plan shall be valid for the period of that building permit’s or site plan’s
validity. Permit(s) for tree removal not issued in connection with a building permit or
a site plan shall become void one hundred eighty (180) days after the issue date on the
permit.
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3. Action on Permit Application: The Landscape Administrator or the Tree Board shall
grant a tree removal permit based on the following criteria:
a. Whether or not a reasonable accommodation or alternative solution can be made to
accomplish the desired activity without the removal of the tree;
b. The cost of preserving the tree;
c. Whether the tree is worthy of preservation. Trees listed as marginal trees in
Appendix C usually are not considered worthy of preservation depending on the
individual characteristics of the tree;
d. The effect of the removal on erosion, soil moisture, retention, flow of surface waters,
and drainage systems;
e. The need for buffering of residential areas from the noise, glare, and visual effects of
nonresidential uses;
f. Whether the tree interferes with a utility service;
g. Whether the proposed tree replacement pursuant to the Tree Replacement
Requirements hereof adequately mitigates the removal of the tree;
h. Whether the removal affects the public health, safety or welfare.
J. Tree Replacement Requirements.
1. Tree Replacement: In the event that it is necessary to remove a protected tree as specified
in Section E through G herein, the party (other than franchise utility companies)
removing the tree shall be required to replace the protected trees being removed with
quality trees as defined herein. A sufficient number of trees shall be planted to equal or
exceed the diameter (measured at 4.5’ above ground level) of each tree removed. This
mitigative measure is not meant to supplant good site planning. Tree replacement will be
considered only after all design alternatives which could save more existing trees have
been evaluated and reasonably rejected. Said replacement trees shall be a minimum of 3”
diameter (measured at l’ above ground) and seven feet (7’) in height when planted.
2. Replacement Procedures:At the time of review, the agent responsible for replacement, the
time of replacement and the location of the new trees will be determined by the
Landscape Administrator. The replacement trees shall be located on the subject site
whenever possible. However if this is not feasible, the Landscape Administrator has the
authority to allow the planting to take place on another property, including public
property. Franchise utility companies shall be exempt from this requirement. If the
Landscape Administrator approves the planting of replacement trees more than 30 days
after the removal of protected trees, the applicant shall provide the Landscape
Administrator with an affidavit that all replacement trees will be planted within six
months. Any replacement tree required by this ordinance must be covered by a one-year
warranty that is acceptable to the Landscape Administrator.
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3. Tree Reforestation Fund: In a densely forested area, the applicant, upon approval of the
Landscape Administrator, may make a payment into the Tree Reforestation Fund in lieu
of planting the replacement tree on the subject site. The funds shall be used only for
purchasing and planting trees on public property or acquiring wooded property which
shall remain in a naturalistic state in perpetuity. The amount of the payment required for
each replacement tree shall be calculated based on a schedule published annually by the
Landscape Administrator which sets forth the average cost of a quality tree added to the
average cost of planting a tree.
K. Additional Duties and Authorities of the Tree Board
The Tree Board shall have the responsibility to review and grant a tree removal permit for the
following land use:
1. Any public or recreational use that is deemed acceptable to the Tree Board.
2. Any private use that is deemed acceptable to the Tree Board that usually requires large
areas of open space.
3. In granting the tree removal permit, the Tree Board is authorized to impose whatever
conditions of approval that is deemed necessary by the Tree Board.
L. Tree Protection.
A major purpose of this ordinance is to protect all protected trees which are not required to
be removed to allow approved construction to occur. The following procedures are required:
1. Construction Plan Requirements: All construction plans shall include the requirements
noted in Appendix E.
2. Prohibited Activities: The following activities shall be prohibited within the limits of the
critical root zone of any protected tree subject to the requirements of this ordinance.
a. Material Storage: No materials intended for use in construction or waste materials
accumulated due to excavation or demolition shall be placed within the limits of the
critical root zone of any protected tree. However, this restriction shall not apply to
material storage in areas exempt from the tree protection and replacement
requirements (e.g. building pad, driveway, patios, parking lot, etc.)
b. Equipment Cleaning/Liquid Disposal: No equipment shall be cleaned or other liquids
deposited or allowed to flow overland within the limits of the critical root zone of a
protected tree. This includes, without limitation, paint, oil, solvents, asphalt,
concrete, mortar or similar materials.
c. Tree Attachments: No signs, wires or other attachments, other than those of a
protective nature shall be attached to any protected tree.
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d. Vehicular Traffic: No vehicular and/or construction equipment traffic or parking shall
take place within the limits of the critical root zone of any protected tree other than on
an existing street pavement. This restriction does not apply to single incident access
within the critical root zone for purposes of clearing underbrush, establishing the
building pad and associated lot grading, vehicular traffic necessary for routine utility
maintenance or emergency restoration of utility service or routine mowing operations.
e. Grade Changes: No grade changes shall be allowed within the limits of the critical
root zone of any protected tree unless adequate construction methods are approved by
the Landscape Administrator or if grading is as directed by the city’s drainage
inspector.
f. Impervious Paving: No paving with asphalt, concrete or other impervious materials in
a manner which may reasonably be expected to kill a tree shall be placed within the
limits of the critical root zone of a protected tree except as otherwise allowed in this
ordinance.
3. Preserved Tree: A protected tree shall be considered to be preserved only if a minimum
of 75% of the critical root zone is maintained at undisturbed natural grade and no more
than 25% of the canopy is removed due to building encroachment.
4. Prior to Construction: The following procedures shall be followed on all types of
construction projects (i.e. residential subdivisions, commercial, multi-family, industrial
developments, residential builders and municipal/public).
a. Tree Flagging or Marking: Trees that are approved by the Landscape Administrator
for removal shall be flagged with bright fluorescent orange vinyl tape wrapped
around the main trunk or marked with bright fluorescent orange paint at a height of 4'
or more such that it is very visible to workers operating construction equipment. This
shall not include the flagging or marking of all protected trees adjacent to right-ofway
within approved residential subdivisions during the construction of the roadway.
Trees that are not flagged or marked shall be saved and protected by fencing in
accordance with the requirements hereinafter.
b. Protective Fencing: In those situations where a protected tree is so close to the
construction area that construction equipment might infringe on the root system or is
within twenty feet (20’) of the construction area, a protective fencing shall be
required between the outer limits of the critical root zone of the tree and the
construction activity area. Four feet (4’) high protective fencing shall be supported at
a maximum of 10’ intervals by approved methods. All protective fencing shall be in
place prior to commencement of any site work and remain in place until all exterior
work has been completed.
c. Bark Protection: In situations where a protected tree remains in the immediate area of
intended construction, the tree shall be protected by enclosing the entire
circumference of the tree with 2" x 4" lumber encircled with wire or other means that
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do not damage the tree. The intent here is to protect the bark of the tree against
incidental contact by construction equipment.
5. Permanent Construction Methods
a. Boring: Where it is not possible to trench around the critical root zone of a protected
tree, boring of utilities under the protected tree shall be required. The length of the
bore shall at least be the width of the critical root zone and the depth of the bore shall
at least be twenty-four inches (24”).
b. Grade Change: In situations where the grade change within the critical root zone of a
protected tree exceeds the limits noted in Section L.2.e herein, the procedures noted
in the City standard detail sheet shall be required.
c. Trenching: All trenching shall be designed to avoid trenching across the critical root
zone of any protected tree. Although this section is not intended to prohibit the
placement of underground services such as electric, phone, gas, etc., the placement of
these utilities is encouraged to be located outside of the critical root zone of protected
trees. Irrigation system trenching shall be placed outside of the critical root zone with
only the minimum required single head supply line allowed within that area placed
radially to the tree trunk.
d. Root Pruning: All roots 2”or larger in diameter which are exposed as a result of
trenching or other excavation shall be cut off square with a sharp medium tooth saw
and covered with pruning compound within 2 hours of initial exposure.
M. Tree Pruning Restrictions.
1. General: No protected tree should be pruned in a manner which significantly disfigures
the tree without proper cause or in a manner which would reasonably lead to the death of
the tree.
2. Permit Requirements: All franchise utility companies shall be required to maintain at the
City a set of pruning specifications (updated annually) to be followed by all pruning
contractors working for the company within the City. Prior to beginning any pruning not
requested by the owner of the tree, the contractor for a non-franchise entity shall submit
to the City an application for a pruning permit for approval. Utility companies may prune
trees as necessary to maintain safe and reliable service or to re-establish disrupted electric
service without obtaining a permit.
3. Allowed Pruning: The Landscape Administrator may approve pruning of a protected tree
in cases where protected trees must be strategically pruned to allow construction or
demolition of a structure. When allowed, all pruning shall be in accordance with Section
L.3 above, approved Arboricultural techniques and the recommendations of Appendix F.
This section is not intended to require a tree permit for reasonable pruning performed or
contracted to be performed by the owner of the tree when unrelated to construction
activity.
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4. Required Pruning: The owners of all trees adjacent to public right-of-way shall be
required to maintain a minimum clearance of ten feet (10’) above the traveled pavement
or curb of a public street. Said owners shall also remove all dead, diseased or dangerous
trees, or broken or decayed limbs which constitute a menace to the safety of the public.
The City shall also have the right to prune trees overhanging within public right-of-way
which interfere with the proper spread of light along the street from a street light or
interfere with visibility of any traffic control device or sign or as necessary to preserve
the public safety.
5. Tree Topping: It shall be unlawful as a normal practice for any person, firm, or city
department to top any street tree, park tree or other tree on public property. Trees
severely damaged by storms or other causes, or certain trees under utility wires or other
obstructions where other pruning practices are impractical may be exempted from this
ordinance at the determination of the Landscape Administrator.
N. Tree Planting Restrictions.
1. Overhead Lines: Any required replacement trees shall not be planted within an area such
that the mature canopy of the tree will be within ten feet (10’) of overhead utility lines.
2. Proximity to Utilities: Any required replacement trees or street trees shall not be planted
within five feet (5’) of electrical facilities (underground or surface), public utility lines,
including water lines, sewer lines, transmission lines or other utilities. No trees shall be
planted within ten feet (10’) of a fire hydrant. Shrubs will be permitted outside of the
minimum clearance of surface electrical facilities established by the franchise electrical
company.
3. Street Corners: No street tree shall be planted closer than twenty-five feet (25’) of any
street corner, measured from the point of nearest intersecting curbs or curblines.
O. Enforcement.
1. Building Permit: No building permit shall be issued unless the applicant signs an
application or permit request which states that all construction activities shall meet the
requirements of this ordinance. The Building Official shall make available to the
applicant a copy of this ordinance or a condensed summary of the relevant aspects
pertaining to the type of permit requested.
2. Acceptance of Improvements: No acceptance of public improvements shall be authorized
until all fines for violations of this ordinance have been paid to the City or otherwise
disposed of through the Municipal Court. No acceptance of public improvements shall
be authorized until all replacement trees have been planted or appropriate payments have
been made to the Tree Reforestation Fund.
3. Certificate Of Occupancy: No Certificate of Occupancy shall be issued until all fines for
violations of this ordinance have been paid to the City or otherwise disposed of through
the Municipal Court. No Certificate of Occupancy shall be issued until all replacement
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trees have been planted or appropriate payments have been made to the Tree
Reforestation Fund.
4. Notwithstanding the above provisions, public improvements may be accepted and
Certificate of Occupancy may be issued before all trees have been replaced if a fiscal
security is posted in an amount equal to the prevailing rate for installed trees with a one
(1) year guarantee, plus fifteen percent (15%) to cover administrative costs.
P. Conflicting Ordinances
That all ordinances of the City in conflict with the provisions of this ordinance be, and the
same are hereby, repealed and all other ordinances of the City not in conflict with the
provisions of this ordinance shall remain in full force and effect
.Q. Severability
Should any paragraph, sentence, subdivision, clause, phrase or section of this ordinance be
adjudged or held to be unconstitutional, illegal or invalid, the same shall not affect the
validity of this ordinance as a whole or any part or provision thereof, other than the part so
declared to be invalid, illegal or unconstitutional, and shall not affect the validity of the
Comprehensive Zoning Ordinance as a whole.
R. Penalty
1. Any person, firm, corporation, agent, or employee thereof who violates the provisions of
Section D through H of this ordinance shall be guilty of a misdemeanor and upon
conviction hereof shall be fined not to exceed One Hundred Dollars ($100.00) per
diameter inch of the tree(s) removed or damaged.
2. Any person, firm, corporation, agent or employee thereof who violates any other
provisions of this ordinance shall be guilty of a misdemeanor and upon conviction hereof
shall be fined not to exceed Five Hundred Dollars ($500.00) for each incident. The
unlawful injury, destruction or removal of each protected tree shall be considered a
separate incident and each incident subjects the violator to the maximum penalty set forth
herein per tree.
3. Removal of Public Trees: It shall be deemed a violation of this ordinance for any person
or firm to engage in the business or occupation of pruning, treating, or removing street or
park trees within the City without first procuring approval from the Landscape
Administrator.
S. Appendices
It is anticipated that the following appendices will be changed periodically by the Landscape
Administrator in response to changes in the administration of this ordinance.
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T. Effective Date
This ordinance shall take effect immediately from and after its passage on third and final
reading and the publication of the caption, as the law and charter in such cases provide.
First reading approved on the 22nd day of June, 1998.
Second reading approved on the 13th day of July, 1998.
DULY PASSED on the third and final reading by the City Council of the City of Mansfield,
Texas, this 27th day of July, 1998.
David Harry,
MayorATTEST:
Judy Howard,
City SecretaryAPPROVED AS TO FORM AND LEGALITY
Allen Taylor,
City AttorneyOrdinance No. ______
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APPENDIX A
TREE EXHIBIT
Critical Root Zone (CRZ)
: The area of undisturbed natural soil around a tree defined by aconcentric circle with a radius equal to the distance from the trunk to the outermost portion of
the dripline.
Drip Line
: A vertical line run through the outermost portion of the canopy of a tree andextending to the ground.
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APPENDIX B
TREE DIAMETER MEASUREMENT
ON A SLOPE IRREGULAR SWELLING
(requires discretion by
Landscape Administrator)
MULTI-TRUNK TREE LEANING TREE
Source: COA
Diameter Measurement
: The diameter of a tree shall be measured as shown above. Thediameter of a multi-trunk tree shall be the total diameter of the largest trunk plus half the
diameter of each additional trunk.
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APPENDIX C
Quality Trees
Common Name Botanical Name Identification Notes
Pecan Carya illinoensis Pecan fruit, compound leaves
Cedar Elm Ulmus crassifolia Deciduous, 1"-2" dark green leaves
Shumard Red Oak Quercus shumardii Deep pointed lobes in leaves
Texas Red Oak Quercus texana Vertical multi-trunk shape
Live Oak Quercus virginiana 1 ½" dark green pointed leaves
Bur Oak Quercus macrocarpa Large acorn, leaf border at end
Post Oak Quercus stellata Deep lobes, rounded tip on leaf
Black Jack Oak Quercus marilandica Leathery 3"-7" leaf, no lobes
Lacebark Elm Ulmus parvifolia Small dark serrated green leaves
Chinese Pistache Pistacia chinensis 3" sickle leaflets, fall color
Sweetgum Liquidambar styraciflua Star shaped leaf
Austrian Pine Pinus nigra Two needles
Chinquapin Oak Quercus muhlenbergii Oblong 4"-6" serrated leaf
Southern Magnolia Magnolia grandiflora Large evergreen Leaf, white flower
Bald Cypress Taxodium distichum Feather-like foliage, fall color
Caddo Maple Acer barbatum 'Caddo' Five-lobed leaf
Texas Hickory Carya texana Five leaflets, 1"-2" nut
Western Soapberry Sapindus drummondii 18" compound leaf, ½" clear fruit
Red Cedar Juniperus virginiana Native, pyramidal shape
Marginal Trees
Common Name Botanical Name Identification Notes
Cottonwood Populus deltoides Deep fissures in bark, heart shape leaf
Mesquite Prosopis glandulosa Lacy open foliage, 10" bean fruit
American Elm Ulmus americana 'V' shaped main branching
Slash Pine Pinus elliotti Tall cylindrical shape
Honeylocust Gleditsia triacanthos Lacy foliage, thornless variety only
Japanese Black Pine Pinus thunbergii Twisted growth, dark green needles
Deodar Cedar Cedrus deodara Large pyramidal evergreen
Understory Trees
Common Name Botanical Name Identification Notes
Redbud Cercis canadensis Purple/white flower in spring
Mexican Plum Prunis mexicana White flower, exfoliating bark,thorns
Possumhaw Holly Ilex decidua Showy orange/red fruit, deciduous
Golden Raintree Koelrutaria paniculata Yellow flower, panicled fruit
Yaupon Holly Ilex vomitoria Evergreen, light bark, red fruit
Cherry Laurel Prunus caroliniana Glossy evergreen foliage, shrubby
River Birch Betula nigra White flaky bark
Eves Necklace Sophora affinis Dull green tear-dropped shape leaf
Persimmon Diospyros virgininana Thin, smooth, pale grey bark
Rusty Blackhaw Viburnum rufidulum Glossy, dark green leaved, white flowers
Wax Myrtle Myrica cerifera Light olive-green leaves, pale blue berries
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APPENDIX D
LIST OF ITEMS REQUIRED ON TREE SURVEY
1. Appropriate Title (i.e. Tree Removal Exhibit, or Tree Survey)
2. Title block which includes street address, lot and block, subdivision name, city and date of
preparation.
3. North arrow, graphic and written scale in close proximity
4. Scale at a size no larger than 1” = 100’ for residential development; scale to be determined by the
Landscape Administrator for non-residential and home building activities.
5. Name, address and phone of owner and person preparing the document
6. Location of all right-of-way lines and public easements
7. Location of all buildings, structures, pools, parking and other improvements which are existing or
intended on the lot
8. Areas of cut/fill with amount of each shown and flow lines shown
9. Existing and proposed spot elevations, grades and major contours, along with existing landscaping,
streams, ponds and major natural features.
10. Areas of no disturbance labeled as “No Disturbance Area”. This area must be clearly marked on the
plan and surrounded with protective fencing on the ground. A single incidence removal of
underbrush and vines is allowed.
111. All protected trees shown individually on the plan.
2 Canopy Trees 6" or greater in size andUnderstory Trees 2" or greater in size. Trees in close proximity that all have a caliper of less than
four inches (4") may be designated as a group of trees with quantity of quality, marginal and
understory trees shown. (see Appendix C)
12. The location of protected trees must be tied by horizontal control (i.e. dimensions from lot lines, or
placed through coordinates determined via survey.)
13. All protected trees shown with diameter (4.5' from the ground), common name and condition.
14. Any proposed replacement trees shown with caliper size, common name of tree and mature size.
15. Graphic representations distinguishing protected trees that will be saved versus those that will be
removed.
16. Phasing of tree survey along with phasing of the development is permitted.
Notes:
1
The Landscape Administrator shall have the authority to designate areas as “no disturbance” areas where a surveywould not be required due to no intended construction.
2
An area may be designated as a “No Disturbance Zone” on the plan when approved by the LandscapeAdministrator and trees within that zone are not required to be individually identified on the plan.
3
The Landscape Administrator shall have the authority to exempt any of the above items that he deems to be notapplicable.
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APPENDIX E
CONSTRUCTION PLAN REQUIREMENTS
The following shall be required as a part of all construction plans submitted to the City when tree removal
or tree protection is required during any phase of site work or construction.
1. A Tree Preservation Detail Sheet shall include the following at a minimum.
a. The requirements of Section L.2 to L.4 shall be noted.
b. A graphics legend to be used throughout the plans for the purposes of showing the following:
Trees to be flagged, protective fencing, trees requiring bark protection, boring, areas of cut and
fill impacting protected trees.
c. Graphic tree exhibit showing the features of a tree to include the critical root zone, trunk, canopy,
drip line and method of diameter measurement (per Appendices A & B).
d. Graphic exhibits showing methods of protection to include snow fences, boarded skirts, etc.
e. Graphic exhibits showing construction methods to include grade changes, boring, trenching etc.
f. Graphic exhibit showing appropriate pruning practices (per Appendix F).
2. All practices which will be employed in meeting the requirements of this ordinance shall be shown
graphically on all applicable sheets within the construction plans.
3. Documents as required in Appendix D herein.
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APPENDIX F
TREE PRUNING RECOMMENDATIONS
When removing a branch, always cut outside the
branch bark ridge and collar. Do not make a flush
cut.
Branches that do not have a distinct collar
should be cut at a right angle to the branch
outside the branch bark ridge.
Trees may have codominant stems, as shown on the
left. If a codominant stem must be removed, cut at
an angle outside of the bark ridge as shown in the
insert at right. Avoid leaving any stub.
When removing heavy limbs, first make an
undercut several inches outside of the collar.
Then remove limb by a second cut an inch or so
outside of the first cut. Remove stub with a
third cut just outside of the collar. (Feucht,
1985)
Managing
Space to Manage Growth
Daniel R. Mandelker*
Oregonians don’t like sprawl, but they don’t like high density either.
—John
A. Kitzhaber, Governor of Oregon
As growth management programs come of age, experience can tell us how they work and what can make them more effective. Strategies that manage space to manage growth are important elements in these programs. Space management directs development to one part of an urban area, but limits it elsewhere, to attain the policies that growth management adopts.
This article examines two longstanding growth management programs that rely on space management: the tiered growth program in San Diego, and the urban growth boundary program in Oregon, as carried out in Portland. The article first reviews the goals that growth management seeks to achieve. It then discusses the San Diego and Portland programs, focusing on the strategies adopted in these programs and the extent to which they were successful. Finally, this article concludes with recommendations for improving space management strategies.
Growth management
began in the 1960s to provide new techniques for managing rapid and uncontrolled
growth through urban sprawl. Though
there is no consensus on a definition of sprawl,
commentators usually characterize it as low-density development that expands
as leapfrog noncontiguous development from the core of metropolitan areas.[1]
Regulations for the Florida state land use planning program define urban
sprawl as premature and poorly planned conversion of rural land, and development
that does not relate to adjacent land uses and does not make maximum use of
existing public facilities.[2]
Critics of sprawl
would point to its many problems.[3]
These include higher capital and operating costs for private and public
facilities, higher transportation and travel costs, and the excessive
consumption of agricultural and sensitive lands.
They also include the deterioration in the quality of life, and social
impacts, such as suburban exclusion and a mismatch of jobs and housing.[4]
The criticism
that urban sprawl increases capital facility and service costs gained major
support in an early influential study. It
showed the cost of servicing scattered and low-density development is much
higher than the cost of servicing compact development at higher densities.[5]
Critics contested these findings,[6]
but most studies conclude that lower densities and urban sprawl do result in
higher capital facility costs.[7]
Studies have also found modest, but cumulatively significant,
reductions in operating costs for compact rather than sprawl development.[8]
These findings are important to the legal basis for growth management
programs that remedy this problem. Courts
have held, and are likely to continue to hold, that land use programs requiring
the orderly provision of services and facilities at optimal cost is a legitimate
governmental objective in growth management.[9]
A related timing
problem is that rapid development may overwhelm a community so that it cannot
provide facilities and services when new development needs them.
Local governments can handle this problem by providing necessary
facilities in advance before growth occurs, but few have the resources to do
so.[10]
Growth management can time development so that local governments
can budget and plan for needed services and facilities.
Policy makers who
became concerned with urban sprawl soon realized that zoning cannot handle the
sprawl problem. Originally a
static system that designated where development could occur, zoning gradually
became a more flexible process in which local governments could review development
proposals as they were presented for review.
Though this process could have controlled the rate, timing, and character
of growth, it did not do so because comprehensive plans, and thus land
development regulations, did not consider these issues.[11]
Because the
problems that drive growth management programs vary, it is difficult to define
what growth management does. The
conventional understanding is that growth management influences the rate,
amount, type, location and quality of growth.
One topology lists four types of controls: adequate public facilities
programs that prohibit development unless adequate public facilities are
available, phased growth programs that determine when to allow development,
urban growth boundary programs that set limits on urban growth, and
rate-of-growth programs that establish a defined growth rate.[12]
These strategies
reflect the various origins of the growth management movement.
Some focus on the provision of public facilities and try to time the
provision of these facilities with new development.
Other strategies manage space, and attempt to regulate the rate of growth
or determine where development should locate. Programs with spatial
dimensions, such as urban growth boundary programs,[13]
control the shape and form of development.
Space management is new to American land use planning, though it has long
been a key element of land use planning in other countries.
An example is the British Green Belt program, which limits the growth
of cities to preserve agricultural land and prevent urban sprawl.[14]
Space management
programs are especially critical because they dramatically affect the spatial
form of development in ways not typical in American tradition.
They are good faith efforts to modify development patterns to provide a
more desirable pattern for urban growth.
Urban growth boundaries, for example, establish a boundary line beyond
which new development cannot occur. These
programs have major effects on the land market because they prevent development
where it otherwise might occur and because they direct development to areas
where it might not otherwise occur. Space
management programs also have an implicit preference for higher-density, compact
urban development in areas where development can occur.[15]
This high-density preference is a corollary to the criticism of
low-density sprawl, which is considered wasteful and difficult to service.
Two major growth
management programs in western cities have made use of space management for over
a quarter of a century. They
deserve study as examples of how these programs work.
One is the tiered system of growth management in San Diego, California.
The other is the urban growth boundary in place in Portland, Oregon,
which the state planning program requires.
San Diego, though
it has cycled through boom and bust periods, is one of the fastest-growing
cities in the country. It is also
one of the most desirable. Growth
management became a major issue in the 1970s, when growth accelerated.
The city was large enough, and had enough undeveloped area, so that a
growth management strategy made sense within the city limits.
When growth became a major problem in the 1970s, the city called in a
national consultant who had prepared and successfully defended a phased growth
program in New York State.[17]
This consultant proposed a tiered growth management program for San
Diego.[18]
The introductory chapter of his report details the purpose and
strategy of the program:
The growth
strategy supports neither extreme of unrestrained expansion nor the complete
cessation of growth. Rather, it
conceives that urban growth will occur in logically defined increments phased
with and/or adjusted to the City’s capacity for accommodating such
increments.[19]
This statement shows that the principal objective of the
program was the provision of facilities needed to serve new development.[20]
Its principal concerns were the staging and timing of growth, the timely
provision of public facilities within areas where growth could occur, and a
requirement that new development should pay the capital costs it requires.[21]
The city also
faced several space management problems.
Downtown and inner city areas were not attracting enough new development,
while excessive development threatened the northern tier.
This type of growth pattern would ultimately have produced low-density
sprawl in outlying areas, while the inner city declined.
The city also has important wetlands, canyons and other natural resource
areas that residents value, which new development threatened.
As adopted, the
program has three growth tiers: an urbanized tier, a planned urbanizing
tier, and an urban reserve tier.[22]
The consultant’s proposal encouraged growth in the urbanized tier,
staged growth in the planned urbanizing tier,[23]
and deferred growth for fifteen to twenty years in the urban reserve.
It also included an environmental tier intended to protect the
area’s canyons, steep slopes and other natural resources, but the city did not
adopt it.[24]
The growth management program only applies to residential
development, because it assumed nonresidential development will carry its
fair share of needed improvement costs and does not affect the need for
schools, parks and libraries.[25]
The
consultant’s proposal included different policies and objectives for each
tier, most of them regulatory, though it proposed other measures, such as
redevelopment, where it was necessary in the urbanized tier.
There was no strategy for allocating growth to designated areas
within the tiers where the program allowed growth.
Neither was enough attention paid to the need for capital improvements in
the urbanized tier, though there was a brief discussion of a capital
improvements program.[26]
In the planned urbanizing tier the city adopted a special benefits
assessment, which the courts eventually upheld,[27]
that carried out the program’s proposal to shift the cost of new facilities
to developers. In the urban reserve
the principal control was large lot zoning at a minimum of ten acres for each
dwelling unit. This type of zoning
protects land from urban growth because the density it allows is too low to
allow development at an intensive scale.
The San Diego
plan creatively used several standard land use measures to manage the rate
and direction of growth, though the options then available limited its choice.
Today, for example, there is greater support for programs that protect
threatened environmental areas.[28]
An innovative development exaction shifted the cost of new public
facilities to developers in the planned urbanizing area.
Problems that arose later reflect, to some extent, the political climate
in which the program began. Its
growth restrictions were partly a response to an initiative proposal that
would have limited growth in the city. Yet
the decision to make large areas unavailable for development was both novel
and dangerous, as the development industry had never faced the obstacle that
large areas of a municipality were off limits.
To reduce opposition to this policy, the city made concessions.
It removed a substantial area from the future urbanizing to the
planned urbanizing tier and dropped the open space tier from the program.[29]
Neither did the city adopt legislation protecting natural resource
and sensitive areas until 1990.[30]
At first, the
program succeeded. Development increased
dramatically in the urbanized areas, and growth in the planned urbanizing
area declined. A major factor in
this shift in development preferences was the absence of a development
exaction in the urbanized areas.[31]
Problems arose
with the facilities benefits assessment in the planned urbanizing area.
Judicial approval of the assessment took seven years,[32] and the collection of
fees then lagged infrastructure needs.[33]
Problems also occurred in the urbanized area.
An obsolete zoning code allowed eight-plex apartment buildings in
single-family neighborhoods, front-yard parking, and other undesirable
design practices that provoked neighborhood objections.[34]
Alarmed residents put pressure on the city to adopt legislation to
protect inner area neighborhoods from multifamily development.[35]
Problems also
arose with the adequacy of public facilities in the urbanized area.
This area attracted development, as the city did not require impact fees
there, so only general budget revenues were available for improving new
facilities to adequate standards. These revenue sources became inadequate soon after the city
adopted the growth management program, when state constitutional initiatives
limited real property tax rates and spending growth. The constitutional limitations made it impossible for
the city to finance needed capital improvements in the urbanized area, so
services and facilities deteriorated or became obsolete. Another problem was that built-up neighborhoods began to
demand higher public facility standards. Planners
had assumed that existing infrastructure in these neighborhoods would be
sufficient.
Demands for more
development put pressure on the urban reserve, an area where the program planned
for development later. Citizens
became concerned when the city council began to shift too much urban reserve
land to the planned urbanizing area, where development could occur.[36]
In 1985, voters adopted an initiative that requires voter approval
for any shift from the urban reserve to the planned urbanizing area,[37]
but this victory was short-lived. Voters
have approved two projects under this initiative, and later initiatives
intended to limit growth failed.[38]
A new form of
low-density development that escapes the 1985 initiative has also become
popular. Developers took advantage
of a city policy that allows clustered developments on four-acre lots in the
urban reserve. This type of development
does not need voter approval under the 1985 initiative because it does not
require reclassification from the urban reserve to the planned urbanizing
area. It also has a ready market
among affluent homebuyers who seek an exclusive residential environment.
The city’s
response to these problems has been slow and inadequate.
It has delayed the implementation of ordinances that protect sensitive
lands and limit the introduction of multifamily development in residential
neighborhoods. The city hired its
original consultant late in 1989 to work with a growth management team on
improvements in the program, but the council rejected their proposals.[39]
The San Diego
history illustrates some common problems faced by spatial growth management
programs. First, events outside the
program had a major effect, especially on the fiscal side.
Judicial delay in the approval of the assessments for capital facilities
is one example. Fiscal measures must receive legal approval before a city
can use them safely, which means that innovation, though necessary, is risky.
Innovative regulatory controls may also face a legal challenge that
delays implementation.
The San Diego
experience also shows that space management can arouse damaging resistance if
it modifies market expectations in land development.
San Diego’s tier program conflicts with the American preference for
minimum development controls.[40]
The density curve is normally less pronounced than what the San Diego
program requires, as development is usually less intensive in the core and
more intensive in outlying areas. Cutting
against this preference meant, over time, that unexpected coalitions would
unite against the program. Developers
tried to undermine the urban reserve, while inner city residents protested the
development and infrastructure problems the program brought.
Political support weakened.[41]
In the urban
reserve, large lot zoning selected to carry out the program may have made it
vulnerable to new development.[42]
Because the program preserved this area by limiting growth, its open
character attracted low-density development, and the voter initiative did
not prohibit it. Although the 1985
initiative did slow development in the urban reserve by requiring voter
approval to shift land to the planned urbanizing area, voters ultimately
approved two projects.
The San Diego
example also shows that attention to implementation detail is essential.
One problem was that the program made development policy choices in each
tier, but did not have a strategy for allocating and phasing development
inside the tiers.[43]
There was no strategy, for example, for allocating development
within the inner urbanized area. This
omission created difficulties when the time came to make development
decisions in the tiers, and the city delayed the adoption of a development
strategy that could deal with these problems.
It finally adopted a plan for the urban reserve in the early 1990s that
made strategic choices in that area, and that called for the preparation of
subarea plans. The city has adopted
some of these plans.[44]
Oregon’s state
land use and urban growth boundary (UGB) programs are well‑known growth
management systems.[45]
A set of state planning goals adopted by the state Land Conservation
and Development Commission (LCDC) are its critical elements.[46]
LCDC reviews local plans and land use regulations and approves them if
they comply with the state goals. Local
land use regulations and decisions must be consistent with the approved
plan. A special tribunal, the Land
Use Board of Appeals (LUBA), hears appeals on land use decisions after
appellants exhaust all local appeals.[47]
The principal
state planning goal that mandates growth management is an urbanization goal
that requires incorporated municipalities to adopt urban growth boundaries.
Local governments must draw a clear line between areas that can urbanize
and areas that must remain non-urban. Local
governments must apply seven factors contained in the urbanization goal to
decide on the size of the urban growth boundary.[48]
Incorporated municipalities apply these factors to designate
enough growth within their UGB to provide an adequate land supply for twenty
years. A UGB can, and usually does,
extend beyond municipal boundaries. The
Portland regional planning agency administers this program in the Portland
metropolitan area and is responsible for making decisions about the
boundary.[49]
The state housing goal, supplemented by legislation,[50] requires local
governments to provide needed affordable housing within UGB boundaries.
A key purpose of
the state program is the preservation of the Willamette Valley in western
Oregon, which has most of the state’s valuable agricultural land and most
of its population. A complementary
agricultural goal requires the preservation of agricultural areas, and the
statutes authorize adoption of exclusive farm use zones to reinforce this
goal.[51]
The statutes also require a minimum eighty-acre lot size in exclusive
agricultural zones.[52]
Enforcement is the primary problem. Growth can occur outside UGBs in
agricultural areas known as “exception lands.”[53]
These are lands either committed to urbanization or needed for other
uses.[54]
Observers agree
that the preservation of agricultural and other natural resource areas were the
primary motivation behind the urbanization goal and the UGB policy.[55]
These priorities mean that the UGB, unlike San Diego tiers, is not primarily
a measure to shape urban growth. The
state planning goals also do not include a strategy for allocating development
within a UGB.
An important
measure of the program’s success is the extent to which growth has occurred
inside, rather than outside, UGBs. Unlike
San Diego, Portland provides public facilities and subsidies inside the
urban growth boundary to encourage development,[56]
although highway congestion is a problem.[57]
Studies of the UGBs, some limited to Portland, do find that a substantial
portion of new development has occurred within UGBs.[58]
A study of development inside the UGBs also showed a substantial
amount of development occurring in or next to the urban core, as intended.[59]
Density increases inside the Portland UGB are impressive,
[60] but densities are lower than the program
intended. Lower densities have occurred
even though zoning that discourages housing or makes it more costly is
prohibited by statute,[61]
and though LCDC requires six to ten units per acre for the Portland area on
undeveloped, residentially-designated lands.[62]
One of the
reasons why higher-density development has not occurred inside the UGBs is that
opposition to this type of development has become increasingly common.[63]
Developers became disillusioned when they could not build at the
expected densities promised by the program at its adoption.[64]
Development has
continued to occur at low densities in so-called exception areas[65]
outside UGBs, often as spurious farms.[66]
This development is substantial and undercuts the urban growth boundary
program, though it has slowed in recent years.[67]
The conversion of land contiguous to UGBs to low-density development
is especially troublesome because it makes the extension of UGBs difficult.
If low-density development occurs on land next to the UGB, it will not be
available for high-density development when the boundary expands.
The UGB must then expand further than it should have been, and
higher-density development must leapfrog over the low-density development that
is in the expansion area. This is
the very type of urban sprawl the urban growth boundary program tries to
prevent.
Oregon legislation
now allows local governments to designate “urban reserve areas” that are
next to UGBs.[68]
These areas provide for the long-term urban expansion and
cost-effective provision of public facilities and services when the UGB
expands.[69]
Local governments are to give priority to urban reserve areas when
expanding urban growth boundaries.[70]
Battle lines over
development are more clearly drawn in the Oregon UGBs than in San Diego because
the UGB marks the boundary between areas where urban development can and
cannot occur. In San Diego, large
lot zoning in the urban reserve area permits low density development.[71]
In Oregon the program does not allow urban development outside the growth
boundary, though low-density residential development in exception areas
undermines this objective. Even so,
there are significant price differences between land inside and outside the
urban growth boundary.[72]
The UGB is not responsible for all of the price increase that has occurred
inside the boundary,[73]
but price increases aggravate affordable housing problems.[74]
A significant
problem in the Oregon UGB program is deciding where development should occur
and at what densities. Development
at low densities inside the UGBs accelerates demands for boundary expansion,
which can damage the goal of preserving agricultural and forest lands.
Higher densities within the UGB reduce demand for boundary expansion but
create opposition from existing neighborhoods.
Housing at higher densities inside the UGB can be expensive and
push lower-income housing outward.[75]
Balancing these competing claims requires a carefully orchestrated
strategy, which is more difficult to secure.
The statutes now authorize density increases within a UGB to meet
housing needs as an alternative to a boundary expansion.[76]
To help resolve
these conflicting pressures, the Portland regional planning agency has adopted
an urban growth management plan as part of its Metro 2040 Growth Concept,
although opposition has slowed implementation.[77]
The plan requires local governments to increase housing densities
and meet housing capacity standards set by the plan.[78]
The Growth Concept, and the statute giving priority to urban reserve
areas in boundary expansions, are the bases for agency regulations for the
review of growth boundary expansions. These
regulations supplement the state planning goals.
The regulations
create a category of “first tier urban reserves” that have a priority in
boundary expansions because they are areas where urban services are most
effectively provided.[79]
A proposed boundary expansion amendment also requires an urban reserve
plan that provides for an average minimum residential density of ten dwelling
units to the acre and a diversity of housing stock.[80]
Plans must ensure the orderly, economic and efficient provision of urban
services through annexation to a city, a city and county agreement on
planning and zoning,[81]
or an urban services agreement.[82]
These regulations reinforce the UGB program by giving priority to
in-boundary expansions to adjacent lands and by requiring reasonable densities
with assurances that adequate services are available.
The Oregon
experience shows how expectations about development opportunities and
coalition shifts can affect program performance.
The development industry welcomed the UGB because it seemed to
provide a commitment to higher-density development inside UGBs.
When opposition arose within the UGB, the industry felt betrayed.
Outside the UGB the agricultural sector, though it usually supports the
conversion of farmland, joined environmentalists in a campaign to
preserve even marginal agricultural lands from development.
The UGB may have become a symbol that polarizes opposing interests and
prevents meaningful consensus on growth management strategies.
Problems in the
San Diego and Portland space management programs do not diminish their
importance as major innovations in land use controls.
Many problems are political. Opposition
arose when program costs not apparent up front became obvious.
Opposition hardened in Portland, for example, to expansion of the
growth boundary and more intensive development within it.[83]
Framing a program around environmental protection, as in Oregon, can
also encourage a rigid defense of environmental areas that prevents compromise.[84]
In San Diego, concessions were made at the beginning, political support
diminished, and the development community applied pressure to weaken the
program.[85]
Voters responded with initiatives that limited the city’s freedom
to make program changes, but later initiatives lost and the use of the ballot
box underscores the loss of political support.[86]
The local basis for the program may also make it more vulnerable.
In Oregon, growth management through growth boundaries is
state-mandated, popular support has continued, and statewide initiatives to
weaken the program have lost.
Improvements in
growth control techniques cannot eliminate political opposition, but they can
improve political acceptance by providing clearer and more effective
strategies for growth management. The
San Diego and Oregon experience shows that growth management programs need
improvement in their strategies for subordinate, second-level policies.
The San Diego tiers and the Oregon UGBs provide a framework for growth,
but subordinate strategies are not as well developed.
1.
Some Conceptual Problems
A perennial
problem for growth management programs is to develop strategies for limiting
development where the program does not want development to take place.
Traditional land use controls cannot accomplish this objective because
they are usually lenient. Local
governments do not use zoning and other controls to place limits on where
development can occur, impose boundaries that identify growth
opportunities, or forcefully direct development to core areas.
The San Diego and Oregon programs made major changes in this system.
They adopted boundaries that decide where development can and cannot
occur, and deliberately directed development to the inner core. Strategies of
this kind can create windfalls for wipeouts problems because they dramatically
affect development opportunities and land prices on each side of the boundary
line. These problems, in turn, can
create significant new legal difficulties for the development control system.[87]
Legal problems
are most difficult on the side of the boundary where development cannot occur.
Development restrictions raise the familiar cry that one group of landowners
must accept deep losses in property value to benefit the rest of the community.
This is a well-known takings problem.
It is significant
that there has not been a successful legal attack against growth restrictions in
either San Diego or Portland. One
reason may be the tradeoffs in development opportunities these programs
provide. They restrict development
in some areas but provide development opportunities elsewhere.
Another explanation may be that the programs provided enough opportunities
for development so that legal attacks on growth restrictions are not
necessary. Shifts of urban reserve
land in San Diego to allow their development, and development opportunities
on exception lands in Oregon, are examples.
The boundary may
also affect expectations in ways that diminish taking of property objections.
The urban growth boundary in Portland, for example, must allow enough
land for twenty years of growth. Since
the boundary is likely to expand when this land supply is no longer available,
adjacent land near the boundary has a good expectation of development in a
reasonable time after twenty years.[88]
The question is whether a restriction on development for this period is
a taking of property. If courts
will accept that a delay in the development of property of this length is not
a taking, then restrictions on development in growth management programs are
safe from a takings attack.
The Ramapo case upheld delays in development to carry out a growth
management program.[89]
There, a growth management program deferred growth for as long as
eighteen years and permitted development only when designated public facilities
and services were available. The New York Court of Appeals rejected a takings claim
because it held the delay was part of a reasonable program for controlling
growth.[90]
A court could apply this kind of reasoning to delays in development
that occur in areas near growth boundaries because those delays are also limited
in time. How much delay a court
will accept is another question.
Supreme Court
cases decided since Ramapo raise other
questions. It is now clear the
courts require compensation for a temporary taking for the period a regulation
was in effect before a court holds it violates the takings clause.[91]
In addition, the Court’s Lucas decision
held a land use regulation that does not allow an economically viable use is a
taking per se.[92]
That case found a per se taking when a beach setback in a coastal
management program deprived a landowner of all economically viable use
of his land.[93]
The Court would not consider the purpose statement in the act as a
basis for upholding the restriction.[94]
The Lucas per se takings rule,
and the requirement that compensation is payable for a temporary taking when
a land use regulation is unconstitutional, could invalidate temporary restrictions
on development in growth boundary programs.
If the program does not allow any development on land outside the growth
boundary, a court could find a temporary taking for the period during which
this restriction was in effect.[95]
In areas further
from the boundary line, the delay in development may be substantial, so an
argument that the program requires only a temporary delay in development may not
apply. In these areas, however, the
economics of a taking claim may discourage a takings attack.
If the landowner believes the discounted development value of her land
at a future date is worth more than what she might recover as compensation in
a takings suit then she will not sue. Discounted
value may be higher because land values will rise as development occurs in
adjoining and surrounding areas.[96]
If a landowner
brings a takings claim, the critical question is whether the land use
restriction is a per se taking because it denies all economically viable use of
the property. What is a denial of
economically viable use is not clear. In
Lucas, the Court did not decide
whether there must be a developmental use of the property to avoid a claim
that a regulation does not allow an economically viable use.[97]
Some cases have held the key question is whether there is a competitive
and realistic market for the land that is subject to restriction.[98]
This means there must be a market of buyers who are willing to buy the
land for development, not for speculation.
It does not mean the land use regulation allows a developmental use of
the property. If this market
exists, there is no taking, but this view may not be a correct interpretation
of the Supreme Court’s Lucas decision.
2.
Control Techniques for Limiting Development
This discussion
of takings problems in growth restriction areas can provide guidance on the type
of controls that can limit development yet not create takings problems.[99]
Exclusive agricultural zoning, as in Oregon, is one option.
Agricultural protection is clearly a legitimate governmental objective,[100]
and the courts uphold agricultural zoning against takings claims when land is
presently used or suitable for agriculture.[101]
A Lucas per se taking does not
arise.
Controls that restrict
development in sensitive environmental areas are other possibilities.
These controls can present takings problems[102]
under the Lucas decision[103]
because they often prevent any developmental uses, but this problem has not
yet been serious. In the wetlands
cases, for example, courts have dismissed takings claims where the
property was not all wetlands, and the landowner could carry out an
economically viable use on that part of the land.[104]
Takings problems have arisen only when a permit denial or regulation
prohibits development on small single lots.[105]
This problem should not occur in undeveloped areas outside growth boundaries
where land holdings are likely to be extensive.
When agricultural zoning or environmental land use regulations are not an option, growth management programs may have to rely on large lot, single-family residential zoning, as in San Diego. Large lot zoning can be an effective restriction on development when it zones densities so low that they discourage development, but that kind of zoning can raise legitimacy and takings problems.
Courts may accept
large lot zoning at low densities when it implements a growth management
program contained in a comprehensive plan.[106]
An important pre-Lucas Maryland case upheld restrictive large lot zoning that
implemented a growth management program in Montgomery County, next to
Washington, D.C.[107]
The county downzoning required two acre zoning to protect watersheds and
a green belt in a fifty-square mile area around a satellite community
designated in a master plan.[108]
The master plan promoted the physical isolation of the community from
urban sprawl, and carried out a corridor plan adopted for the metropolitan
region.[109]
The court relied on the purpose of the master plan to hold that
downzoning was not a taking of property.[110]
Zoning of this
type is more problematic after Lucas
because a court can hold that it deprives a landowner of all economically
viable use of her land. This issue
remains open, though a post-Lucas Maryland case upheld
comprehensive five acre zoning adopted to implement a comprehensive plan.[111]
This zoning protected the Baltimore watershed from unsuitable development
and prevented urban sprawl.[112]
The court held the Lucas per se taking rule did not apply because the zoning restriction
did not leave the property economically idle.[113]
Densities at two
or five acres, which the Maryland cases approved, may prevent development
effectively in areas permanently restricted from growth in growth management
programs.[114]
Low residential densities may still be vulnerable to a takings attack,
though judicial tolerance for very low density zoning when used to implement a
growth management program may be higher than expected.[115]
Low-density zoning may also provide an escape hatch for affluent housing
in areas where growth is not supposed to occur.
Transfer of
development rights (TDR) programs are another strategy that can help avoid
Takings Clause claims in areas where a growth management program prohibits
development. TDR programs help
avoid these problems because they provide for the transfer of development
rights from restricted areas to areas where development can occur.[116]
Compensation paid by buyers of rights to sellers can fully or partially
mitigate a takings claim.[117]
The best example of a TDR program that supports growth management is the
Montgomery County, Maryland program that protects the county’s agricultural
area from development.[118]
Nevertheless, TDR programs in extensive agricultural or natural
resource areas are difficult to implement if the market will not generate the
trades necessary to provide adequate compensation to sellers of rights.
The volume of rights for sale in restricted areas must be in balance with
the growth allowed in growth areas to make a TDR program work.[119]
If this balance does not occur, additional public intervention through
development rights banks that can buy and hold development rights may be
necessary, but banks may be expensive to create and difficult to manage.[120]
Montgomery County may be unique because its location next to the
national capital creates a strong demand for office space.
This demand supports the market for development rights.
B.
Strategies to Intensify Development Where it is Needed
Space management
programs usually encourage higher density development in areas inside the
boundaries to offset restrictions on development outside the boundaries.
Higher density development often occurs as infill in existing
neighborhoods and usually requires upzonings.
Residents of these neighborhoods may object if they believe higher
densities will have a negative effect on their neighborhoods and may attack
upzoning for higher density development as spot zoning.
Courts strike down upzonings as spot zoning if they are incompatible
with the surrounding area and do not provide a public benefit.[121]
This problem has
two dimensions. One problem is at
the design and scale level. A
zoning ordinance may allow intensive development in existing neighborhoods with
poor design or out of scale with its environment.
Neighbors then resist and oppose proposals for new development.
Attention to design and scale in land development regulations can allow
more intensive development that does not destroy existing neighborhood character.
Even good design
is not enough if higher density development is the real objection, which is
often the case. A growth management
strategy for urbanized areas must provide a framework for new development that
existing residents can accept. Adequate
design review, density floors and ceilings in residentially designated areas,
periodic review of how the municipality has dealt with new residential uses,
and the funding of infrastructure “banks” the municipality can draw on
for capital facilities illustrate measures that local governments can consider.[122]
Local governments
may also have to face the impact fee issue in built-up areas, though levying
impact fees in these areas may make it more difficult to attract new
development. The basic issue is
fairness, and deciding when a municipality can shift the cost of new capital
facilities to the private sector. If
new development in established neighborhoods creates a demand for new or
improved facilities, the case for shifting costs to the private side is compelling.[123]
Municipalities
also need to adopt plans for the development of urbanized areas that
decide where new development will go and at what densities.
There are attempts to do just this in plans, such as urban village and
urban center plans, which allocate new development within cities.[124]
Courts will uphold upzonings that implement a comprehensive plan
against objections that they improperly favor an individual landowner at
the expense of his neighbors.[125]
Specifying the intensity of growth that must occur within growth
boundaries can also help. Model
legislation proposed by the American Planning Association requires urban
growth areas to contain land at “minimum densities and intensities.”[126]
They must accommodate a designated percentage of the growth
expected to occur within the region or county in which the urban growth area is
located.[127]
Programs to allow
new development in urbanizing areas are less difficult to manage.
Raw land converts to development in this process, and usually there are
no neighbors who can object that development is too intensive.
Techniques such as floating zones and planned unit development
regulations can authorize new development as it occurs, and require
compliance with the growth management program.
Assuring adequate
public facilities in urbanizing areas is a more difficult problem.
In San Diego and Portland, new development has overwhelmed public
facilities, especially highways, despite attempts to ensure adequate public
facilities as growth occurs. The courts finally upheld the facilities benefit assessment
in San Diego, but exactions on development are more difficult to defend
following Supreme Court decisions that place the burden on municipalities to
justify exactions.[128]
Some transportation facilities, such as highway interchanges and
mass transit, arguably are a public responsibility and not subject to
exaction.
Attempts to
resolve this problem by requiring adequate public facilities before a local
government approves new development do not always succeed. Defining adequate service levels is difficult, matching
incremental development to public facility planning is not easy, and service
deficiencies have encouraged sprawl by forcing development to outlying areas.[129]
A similar “concurrency” requirement that likewise attempts to require
adequate facilities when new development receives approval has also proved
difficult to manage.[130]
There is no magic
fix that can ensure the provision of necessary capital facilities and services
in growth management programs. There
must be adequate public facilities budgeting, firm fiscal support and developer
exactions that have an adequate legal basis.
Space management
strategies that dramatically shape the pattern of development are powerful
control measures in growth management programs. Their primary purpose is to designate areas where growth
cannot occur and where it is encouraged. Like
other land use programs with single-issue or limited objectives, they are
overlays on existing land development regulations. They may pay some attention to development densities in
areas where growth can occur and to development restrictions in areas where
growth cannot occur. They do not
pay enough attention to more detailed subordinate strategies that can manage
growth in growth-designated areas and prohibit growth where the program restricts
it.
This strategic failure makes it
difficult to strike a program balance that can link the decision on how much
area to commit to growth with the decision on how much area to restrict.
Finding the correct balance between growth and growth restriction is the
key that will determine the success or failure of a space management strategy.
The imperative of managing change is
another important lesson from San Diego and Oregon.
Planning for growth management before the fact, in a political
environment that may be uncertain at best, is clearly not the easiest task.
Governments must adopt the most effective strategies available when they
create these programs, but they must also monitor and respond to change.
The alternative, as the Governor of Oregon warns, is the impossible.
* Stamper Professor of Law, Washington University in St. Louis. The author would like to thank Nico Calavita, Bob Einsweiler, Frances Foster, Bob Freilich, Wendie Kellington, Stuart Meck, Doug Porter, and Ed Sullivan for their valuable comments on an earlier draft of this article. Of course, the author’s analysis and opinions are his own.
[1]
The text adopts the definition of sprawl used throughout Transit
Cooperative Research Program, Rep. 39, The Costs of Sprawl—Revisited
(1998).
See also Robert W. Burchell
& Naveed A. Shad, The Evolution of
the Sprawl Debate in the United States, 5 Hastings
West-Northwest J. Envtl. L. & Pol’y 137, 140-42 (1999)
(defining sprawl as “low-density residential and nonresidential intrusions
into rural and undeveloped areas, and with less certainty as leapfrog,
segregated, and land-consuming in
its typical form”).
[2] “Urban sprawl” means urban development or uses which are located in predominantly rural areas, or rural areas interspersed with generally low-intensity or low-density urban uses, and which are characterized by one or more of the following conditions: (a) The premature or poorly planned conversion of rural land to other uses; (b) The creation of areas of urban development or uses which are not functionally related to land uses which predominate the adjacent area; or (c) The creation of areas of urban development or uses which fail to maximize the use of existing public facilities or the use of areas within which public services are currently provided. Urban sprawl is typically manifested in one or more of the following land use or development patterns: leapfrog or scattered development; ribbon or strip commercial or other development; or large expanses of predominantly low-intensity, low-density, or single-use development. See Fla. Admin. Code Ann. § 9J-5.003(134) (1999).
[3]
Although
the anti-sprawl position has considerable appeal, defenders of sprawl
dispute the arguments that sprawl threatens natural resources and creates
higher government costs, and deny that it is a serious social problem. See, e.g.,
Samuel R. Staley, The Sprawling of America: In Defense of the Dynamic City
14-15 (1999) (claiming that the “sprawl index” is declining, that
urban development does not threaten agriculture, that the effect of
suburbanization on local government costs is exaggerated, and that air
quality deteriorates at higher densities). See generally, e.g.,
Peter Gordon & Harry W. Richardson,
Are Compact Cities a Desirable Planning Goal?, 63 J. Am. Plan. Ass’n 95 (1997) (explaining benefits of
urban sprawl, including opportunities for infill development).
See also Ivonne Audriac et
al., Ideal Urban Form and the Dilemma
of the Good Life: Florida’s Growth Management Dilemma, 56 J. Am.
Plan. Ass’n 470 passim
(1990) (noting that sprawl is a response to market preferences, and that
attempts to
control it will
likely drive up land and housing values); Gregg Easterbrook, Suburban Myth, New Republic,
Mar. 15, 1999, at 18 (arguing that sprawl is not entirely negative because
besides the fact that the alternatives and proposals to remedy sprawl are
unrealistic to implement, people actually enjoy some of the effects of
sprawl).
[4] See Reid Ewing, Is Los Angeles-Style Sprawl Desirable?, 63 J. Am. Plan. Ass’n 107, 117-18 (1997). See generally Transit Cooperative Research Program, supra note 1 ; Symposium, Urban Sprawl, 29 Urb. Law. 157, 158-251 (1997) (citing specific examples of increased costs and pollution caused by sprawl).
[5] See generally Real Estate Research Corp., The Costs of Sprawl (1974).
[6] See, e.g., Alan A. Altshuler, Book Review, 43 J. Am. Plan. Ass’n 207, 208 (1977) (asserting that the study underestimated demand for services from higher-density development and mixed density and unit size effects). See generally, e.g., Duane Windsor, A Critique of The Costs of Sprawl, 45 J. Am. Plan. Ass’n 279 (1979) (book review) (commenting on the failure to disentangle density from other factors and a failure to credit sprawl as a response to market preferences).
[7] See Transit Cooperative Research Program, supra note 1 , at 46-49. See also Robert W. Burchell & David Listokin, Land, Infrastructure, Housing Costs and Fiscal Impacts Associated with Growth: The Literature on the Impacts of Sprawl v. Managed Growth 10 (1995) (claiming that planned development and growth can result in reduced costs to communities); Jerry Weitz & Terry Moore, Development Inside Urban Growth Boundaries: Oregon's Empirical Evidence of Contiguous Urban Form, 64 J. Am. Plan. Ass’n 424, 430-34 (1998) (asserting that sprawl and scattered development costs more than contiguous and planned development because it is an inefficient use of land and resources). See, e.g., The Sierra Club, The Dark Side of the American Dream: The Costs and Consequences of Suburban Sprawl (visited Nov. 14, 1998) <http://www.sierraclub.org/sprawl/report98/costs.html#who> (“Providing services to new development has grown so costly in Prince William County, Virginia, near Washington, D.C., that even though the county has the highest property-tax rate in the Commonwealth, every new house brings a $1,688 shortfall.”).
[8] See Transit Cooperative Research Program, supra note 1 , at 50-52.
[9] See Golden v. Ramapo Planning Bd., 285 N.E.2d 291, 301-03 (N.Y. 1972), appeal dismissed, 409 U.S. 1003 (1972).
[10] See Eric Damian Kelly, Community Growth: Policies, Techniques, and Impacts 20 (1993).
[11] See Edward J. Kaiser & David R. Godschalk, Twentieth Century Land Use Planning, 61 J. Am. Plan. Ass’n 365, 365-66 (1995).
[12] See Eric Damian Kelly, Planning, Growth, and Public Facilities: A Primer for Local Officials 16 (1993).
[13] For further discussions of urban growth boundary programs see Tom Daniels, When City and Country Collide 187-209 (1999), V. Gail Easley, Staying Inside the Lines: Urban Growth Boundaries, 16-27 (1992), Douglas R. Porter, Managing Growth in America’s Communities 61-69 (1997), and Ned Farquhar, Zoning Fallout: The Implications of Urban Growth Boundary Designations, Zoning News, Mar. 1999, at 1.
[14] For an early account of this program see generally Daniel R. Mandelker, Green Belts and Urban Growth (1962).
[15] See generally Dowell Myers & Alicia Kitsuse, The Debate Over Future Density of Development: An Interpretive Review (1999) (discussing the density issue and conflicting reports on the impact of sprawl on urban development in California) (on file with author).
[16] For more in-depth commentary on the San Diego program see generally Robert H. Freilich, Battle Against Sprawl: Smart Growth Systems Using the Ramapo Approach (1999); Douglas R. Porter et al., Profiles in Growth Management 81-87 (1996); Nico Calavita, Growth Machines and Ballot Box Planning, 14 J. Urb. Aff. 1 (1992) [hereinafter Calavita, Ballot Box]; Douglas R. Porter, San Diego’s Brand of Growth Management: A for Effort, C for Accomplishment, 48 Urb. Land, at 21 (1989) [hereinafter Porter, Effort]. See also Nico Calavita, Vale of Tiers, Planning, Mar. 1997, at 18 (criticizing San Diego’s growth management program as well-intentioned but ineffective against development interests).
[17] Professor Robert H. Freilich prepared the program as consultant to the city of San Diego. Professor Freilich was renowned for recently having won a major case, Golden v. Ramapo Planning Bd., 285 N.E.2d 291, appeal dismissed, 409 U.S. 1003 (N.Y. 1972), in the New York Court of Appeals, thereby sustaining a growth management program he had developed for the Town of Ramapo (a suburb of New York City). The Ramapo program allowed new development only when adequate public facilities and services were available.
[18] See Robert H. Freilich, A Growth Management Program for San Diego (1976) (on file with author).
[19] Id. at 2-5.
[20] See John W. Witt & Janis Samartino-Gardner, Growth Management v. Vested Rights, One City’s Experience: A Case Study of San Diego, 20 Urb. Law. 647, 650 (1988).
[21] Professor Freilich stated that another purpose of the program was to organize growth in the planned urbanizing tier through a transportation corridor approach. See generally Freilich, supra note 16 .
[22] See Freilich, supra note 18 , at 4-1, 5-1, 6-1.
[23] See id. at 5-2 (“The objective in identifying . . . [planned urbanizing] areas is to channel new growth into them in an orderly, logical sequence that enables the City to expand facilities and services commensurate with growth.”).
[24] Professor Freilich did not propose a transfer of development rights program for the environmental tier, probably because development rights transfer was then a new and untried idea. For two discussions of transfer of development rights and other techniques the city could have used in the environmental tier, see generally Rick Pruetz, Saved By Development (1997) and Jerold S. Kayden, Market-Based Regulatory Approaches: A Comparative Discussion of Environmental and Land Use Techniques in the United States, 19 B.C. Envtl. Aff. L. Rev. 565 (1992).
[25] See Witt & Samartino-Gardner, supra note 20 , at 651.
[26] See Freilich, supra note 18 , at 6-19,
[27] For an analysis of the legal issues suggesting statutory authority and constitutional problems in the program see generally John M. Winters, An Independent Legal Analysis of a Growth Management Program for San Diego (1978) (on file with author).
[28] See, e.g., Ann Louise Strong, Transfer of Development Rights to Protect Water Resources, Land Use L. & Zoning Dig., Sept. 1998, at 3 (discussing TDRs generally, and specifically considering the use of TDRs in four water resource protection programs in the United States). See generally, e.g., Jeanne S. White, Beating Plowshares into Townhomes: The Loss of Farmland and Strategies for Slowing Its Conversion to Nonagricultural Uses, 28 Envtl. L. 113 (1998) (discussing the importance of farming to communities and the tools being used to preserve farmlands in several areas).
[29] See Calavita, Ballot Box, supra note 16 , at 7-8.
[30] See id. at 16. See also Interview with Kenneth E. Sulzer, Executive Director, San Diego Association of Governments (Jan. 25, 1999) (noting that habitat protection areas adopted under the Endangered Species Act, 16 U.S.C. §§ 1531-1544 (1994 & Supp. IV 1998), also restrict growth). See generally Craig Manson, Natural Communities Conservation Planning: California's New Ecosystem Approach to Biodiversity, 24 Envtl. L. 603 (1994) (discussing California’s implementation of the Natural Community Conservation Planning program and the possibility of a balance between endangered species and economic concerns in communities).
[31] See Letter from Nico Calivita, Professor, San Diego State University (Mar. 31, 1999) [hereinafter Calavita Letter] (on file with author).
[32]
See J.W. Jones Co. v. City of San Diego, 203 Cal. Rptr. 580 (Cal.
Ct. App. 1984).
[33] See Calavita, Ballot Box, supra note 16 , at 11 (noting that the considerable time lag before facilities were actually built was a result of the lead-time needed to plan, design, engineer, and actually construct public improvements).
[34] See Porter, Effort, supra note 16 , at 25.
[35] See Calavita, Ballot Box, supra note 16 , at 16.
[36] See Roger W. Caves, Land Use Planning: The Ballot Box Revolution 140-53 (1992).
[37] The hardening of public opposition to development in areas reserved for development occurred in both San Diego and Portland. Without careful examination of growth trends and land availability, however, it is difficult to determine whether public opposition was justified. In Oregon, moreover, popular initiative could not change the program because it was mandated by state law. See id. at 152-53.
[38] See Telephone Interview with Nico Calavita, Professor, San Diego State University (Jan. 20, 1999) [hereinafter Calavita Interview]. In November 1998 voters turned down an initiative that would have established an urban growth boundary for the county. See id.; Caves, supra note 36 , at 153-62.
[39] See Calavita, Ballot Box, supra note 16 , at 17. The proposals included citywide impact fees, level of service (LOS) standards and a capital facilities plan to meet LOS standards, and phasing of new development if it exceeded the demand for transportation facilities beyond what could by accommodated on the basis of the capital facilities plan. In 1987, the city had also adopted an interim development ordinance that set limits on residential construction for eighteen months. See id. at 12.
[40] See Dan Eggen, Local Controls Fail to Restrict Growth, Wash. Post, Aug. 9, 1998, at B1.
[41] See Porter, Effort, supra note 16 , at 22-24. The need to seek voter approval of initiatives to limit the city council’s control over the program indicates the extent to which interest groups perceived a lack of political support. See generally Christopher Leo et al., Is Urban Sprawl Back on the Political Agenda? Local Growth Control, Regional Growth Management, and Politics, 34 Urb. Aff. Rev. 179 (1998) (arguing that attempts to control sprawl have failed, in large part, because regional growth management initiatives have not successfully been distinguished from unpopular growth controls).
[42] Large lot zoning is a problematic zoning technique, and courts have found it unconstitutional when used for exclusionary purposes. See National Land & Inv. Co. v. Kohn, 215 A.2d 597, 612-13 (Pa. 1965). This problem does not seem to have arisen in San Diego.
[43] Developing this kind of strategy was not part of the work program for the growth management plan. See Freilich, supra note 18 , at 1-5.
[44] See Calavita Letter, supra note 31 .
[45] For surveys of the Oregon program, see generally American Planning Ass’n, Legislative Guidebook Phases I & II, Interim Edition 6-43 (1998); Gerrit Knaap & Arthur C. Nelson, The Regulated Landscape: Lessons on State Land Use Planning from Oregon (1992); Carl Abbott, The Portland Region: Where City and Suburbs Talk to Each Other—and Often Agree, 8 Hous. Pol’y Debate 11 (1997); Robert L. Liberty, Oregon’s Comprehensive Growth Management Program: An Implementation Review and Lessons for Other States, 22 Envtl. L. Rep. (Envtl. L. Inst.) 10,367 (1992); and Edward J. Sullivan, Marking the Twenty-Fifth Anniversary of SB 100, Or. L. Rev. (forthcoming). For a critique of state land use systems, see generally Jerry Weitz, Evolution of State Sponsored Land Use Planning (forthcoming 1999).
[46] These goals were legislatively mandated upon creation of the UGB. See Or. Rev. Stat. §§ 197.225-.245 (1991).
[47] The term “land use decision” is defined in id. § 197.015(10), and a rich and varied case law that tends to lead the Land Use Board of Appeals to review most local actions affecting land use in case of doubt.
[48]
The seven factors are:
(1) the
demonstrated need to accommodate long‑range urban population growth
requirements consistent with LCDC goals;
(2)
the need for housing, employment opportunities, and livability;
(3) the
orderly and economic provision for public facilities and services;
(4) the
maximum efficiency of land uses within and on the fringe of the existing
urban area;
(5)
the environmental, energy, economic, and social consequences;
(6) the
retention of agricultural land as defined, with Class I the highest priority
for retention and Class VI the lowest priority; and
(7) the
compatibility of the proposed urban uses with nearby agricultural activities.
Department of Land Conservation & Dev., Oregon’s Statewide Planning Goals and Guidelines (1995). The first two factors are called the “need” factors.
[49] See Or. Rev. Stat. §§ 197.301-.302.
[50] The housing requirements are at id. §§ 197.303-.314. Section 197.307(3)(a) provides an example of one such requirement:
When a need has been shown for housing within an urban growth boundary at particular price ranges and rent levels, needed housing, including housing for seasonal and year-round farmworkers, shall be permitted in one or more zoning districts or in zones described by some comprehensive plans as overlay zones with sufficient buildable land to satisfy that need.
[51] See id. § 215.203.
[52] See Or. Rev. Stat. § 215.780 (Supp. 1998). Smaller lot sizes are allowed as exceptions under strict conditions. See id. §§ 215.780(2)(a)-(b). The statute also requires an 80-acre lot size minimum for forest zones, and a 160-acre minimum for the rangeland agricultural area. See id. §§ 215.780(1)(b)-(c).
[53]
See §§ 197.732(1)(a)-(c). See
also 1000 Friends of Oregon v. Land Conservation and Development
Commission, 724 P.2d 268, 279 (Or. 1986) (explaining the three types of
exceptions local governments can use under sections 197.732(1)(a)-(c)).
[54] See Or. Rev. Stat. §§ 197.732(1)(a)-(c) (1991 & Supp. 1998).
[55] See Wendie L. Kellington, Oregon’s Land Use Program Comes of Age: The Next 25 Years, Land Use L. & Zoning Dig., Oct. 1998, at 3-4; Weitz & Moore, supra note 7 , at 431. But see Easley, supra note 13 , at 5 (quoting purposes of the UGB for Salem, which also include the efficient and economic provision of services, and the matching of services with population growth).
[56] See Calavita Interview, supra note 38 .
[57] See Kellington, supra note 55 , at 4.
[58] See, e.g., id. (indicating that the Portland UGB is essentially full); Weitz & Moore, supra note 7 , at 424 (“[M]ore than 90 percent of Oregon’s new residents between 1980 and 1989 located inside UGBs.”).
[59] See Weitz & Moore, supra note 7 , at 429 tbl.3.
[60]
See Rachel L. Schowalter, Reuse,
Restore, Recycle: Historic Preservation as an Alternative to Sprawl, 29 Envtl.
L. Rep. (Envtl. L. Inst.) 10,418, 10,421 (1999) (“Since Portland,
Oregon, adopted its urban growth boundary in 1975, Portland’s population
has grown by almost 50 percent, but it has used only 2 percent more
land.”).
[61] See Or. Rev. Stat. § 197.307(6) (1998). The statute provides that local governments must also have “approval standards” and “special conditions” which are “clear and objective and shall not have the effect, either in themselves or cumulatively, of discouraging needed housing through unreasonable cost or delay.” Id. See also Rogue Valley Ass’n of Realtors v. City of Ashland, LUBA No. 97-260 (Or. Land Use Bd. App. Sept. 24, 1998) (invalidating approval standards in a steep slope ordinance).
[62] See Or. Admin. R. 660-007-035 (1998).
[63]
See Editorial, Growth Land-Use
Plans Must Be Enforced, Atlanta J.,
Nov. 12, 1998, at A26.
[64] See Interview with Duane Desiderio and Grant Madsen, Representatives of the National Association of Homebuilders, Dallas, Tex. (Jan. 13, 1999).
[65] Or. Rev. Stat. §§ 197.73(1)(a)-(c) (1991 & Supp. 1998). These are areas that are already developed for rural residential homesites or for commercial or industrial uses, or are areas “committed” to development because of parcelization or installation of services or because surrounding development makes farming and forestry impracticable. See Liberty, supra note 45 , at 10,387. See also 1000 Friends of Oregon v. Land Conservation & Dev. Comm’n, 724 P.2d 268, 277-79 (Or. 1986) (explaining genesis, application, and mechanics of exception areas).
[66]
See Nyran Rasche, Protecting
Agricultural Lands in Oregon: An Assessment of the Exclusive Farm Use Zone
System, 77 Or. L. Rev. 993,
997 (1998).
[67] See Interview with Edward J. Sullivan, Attorney, Portland, Or. (Jan. 31, 1999).
[68] See Or. Rev. Stat. § 195.145 (Supp. 1998). The statute does not specify the techniques that local governments must use to carry out this purpose, but states instead that the Land Conservation and Development Commission “shall provide to local governments a list of options, rather than prescribing a single planning technique, to assure the efficient transition from rural to urban use in urban reserve areas.” Id. Designation of urban reserve areas is voluntary, but the LCDC may require a designation in major metropolitan areas. Prohibiting the subdivision of land is one technique that can keep urban reserve land clear for future development.
[69] See id. § 195.145(4).
[70] See id. § 197.298(1)(a).
[71]
See generally Freilich,
supra note 18
.
[72] See Gerrit J. Knaap, The Price Effects of Urban Growth Boundaries in Metropolitan Portland, Oregon, 61 Land Econ. 26, 32-33 (1985); Arthur C. Nelson, Using Land Markets to Evaluate Urban Containment Programs, 52 J. Am. Plan. Ass’n 156, 160 (1986).
[73]
See Knaap, supra
note 72
, at 31; Nelson, supra note
72
, at 162.
[74] Housing affordability is problematic because of the prevailing, fairly low, average income in the area. The rise in housing prices is also due, in part, to the emergence of a fairly high-income segment of the labor force that wants large homes, even on small lots. See Letter from Douglas R. Porter, President, Growth Management Institute (Feb. 22, 1999) (on file with author).
[75] See id.
[76] See Or. Rev. Stat. § 197.296(4)(b) (Supp. 1998). Model legislation proposed by the American Planning Association requires monitoring of an urban growth boundary to ensure that land supply remains adequate. See American Planning Ass’n, supra note 45 , § 6.201.1(9).
[77] See Robin Franzen & Brent Hunsberger, Have We Outgrown Our Approach to Growth?, Oregonian, Dec. 13, 1998, at A1.
[78] See Metropolitan Regional Service District, Urban Growth Management Functional Plan (last modified Feb. 2, 1999) <http://www.multnomah.lib.or.us/metro/growth/tfplan/ funcplan.html>.
[79] See Portland, Or. Metropolitan Code § 3.01.010(e) (1993) available at <http://www.multnomah.lib.or.us/metro/glance/metcode/metcode1.html>.
[80] See id. §§ 3.01.012(e)(4)-(5).
[81] See id. § 3.01.012(e)(1).
[82]
See id. § 3.01.012(e)(2). In
addition, the expansion must assist in compliance with the Growth
Concept or other statutory or regulatory requirements for land within an
urban growth boundary. See
id.
[83]
Opposition
to high-density development near transit stations is an example.
See Douglas R. Porter, Transit-Focused
Development: A Progress Report, 64
J. Am. Plan. Ass’n 475, 485 (1998) (noting that transit-focused
development has encountered neighborhood resistance and little
governmental leadership in four regions).
Porter notes that some transit-oriented development has occurred in
the Portland area. See
id.
In San Diego, transit-oriented development has been limited by the location of transit lines, limited land availability, market problems, and concerns about residential development that was perceived as not paying its own way. See Marlon G. Boarnet & Nicholas S. Compin, Transit-Oriented Development in San Diego County: The Incremental Implementation of a Planning Idea, 65 J. Am. Plan. Ass’n 80, 90-92 (1999).
[84] See Daniel R. Mandelker, Environmental Policy: The Next Generation, 64 Town Plan. Rev. 107, 108-09 (1993).
[85]
See id.
[86]
See id.
[87]
It is
not clear, of course, that urban growth boundaries and development tiers
are entirely responsible for the price effects that occur where these
controls are used. An answer to
the cause-and-effect question is not important, however, to landowners
inside and outside the boundary. Inside
the growth boundaries, higher land prices create pressure for intense
development, and can create equity problems if higher prices mean that
lower income households cannot find adequate housing.
It should also be pointed out that dramatic price differences on
either side of the boundary are only different in degree from the price
differentials that always occur in developing areas.
In the absence of a growth boundary, however, the price curve will
slope gradually. There will not
be the dramatic fall-off that occurs at the boundary line.
See Tom
Daniels, When City and Country Collide: Managing Growth in the Metropolitan
Fringe 190 (1999); Keith W. Dearborn & Ann M. Gygi, Planner’s
Panacea or Pandora’s Box: A Realistic Assessment of the Role of Urban
Growth Areas in Achieving Growth Management Goals, 16 U.
Puget Sound L. Rev. 975, 977-78 (1993).
[88] In Portland, the metropolitan district has defined the “urban reserve” as “land likely to be needed . . . for a 30 to 50 year period.” Portland, Or. Metropolitan Code § 3.01.010 (1998), available at <http://www.multnomah.lib.or.us/metro/glance/metcode/ metcode1.html>. However, under the rules that apply to the program, land closest to the urban growth boundary are likely to be considered first in any urban growth boundary amendment.
[89] See Golden v. Ramapo Planning Bd., 285 N.E.2d 291 (N.Y. 1972), appeal dismissed, 409 U.S. 1003 (1972).
[90]
See id. at 304-05.
[91] See First English Evangelical Lutheran Church v. Los Angeles County, 482 U.S. 304, 318-19 (1987). Language in First English suggests that a temporary moratorium on development might not be a taking. See id. at 321 (noting that the Court did not have before it a “case of normal delays” in obtaining building permits, zoning changes, and the like).
[92] See Lucas v. South Carolina Coastal Council, 505 U.S. 1003, 1014-19 (1992).
[93]
See id.
[94] See id. at 1031 (“We emphasize that to win its case South Carolina must do more than proffer the legislature’s declaration that the uses Lucas desires are inconsistent with the public interest . . . .”).
[95]
Similar
issues arise when communities impose moratoria, either to provide an
opportunity to revise comprehensive plans and land use regulations, or to
prohibit development until public facilities are adequate to serve the new
development. If the moratorium
is a taking because it prohibits all development during the moratorium
period, a court could award compensation for the time the moratorium was
in effect. See Daniel
R. Mandelker, Land Use Law § 6.11 (4th ed. 1997).
[96]
If a landowner delays in bringing a takings claim, the delay may work
against her because a court may hold that a self-imposed delay means a
landowner does not have investment-backed expectations that were frustrated
by the development restriction. See Dodd v. Hood River County, 136 F.3d 1219, 1230 (9th Cir.);
Tahoe-Sierra Preservation Council, Inc. v. Tahoe Reg’l Planning Agency, 34
F. Supp.2d 1226, 1240-41 (D. Nev. 1999) (appeal pending).
Courts consider investment-backed expectations when they apply the Penn
Central balancing test to takings claims.
See Penn Cent. Transp. Co. v. New York City, 438 U.S. 104, 123-35
(1978) (providing three relevant factors to consider when examining a
takings claim: (1) the economic impact of the regulation on the landowner,
(2) the extent to which the regulation interferes with investment-backed
expectations, and (3) the character of the governmental action).
An exception to the Lucas per se taking rule may also bar landowners who bought land after the UGB was adopted from making takings claims. Lucas held that property was subject to “background principles” of state law. See Lucas at 1029. Although the Court did not explain what this term means, some courts have held that a landowner who buys land takes title subject to legislation adopted before she acquired title. See, e.g., Gazza v. New York Dep’t of Envtl. Conservation, 679 N.E.2d 1035, 1040-42 (N.Y. 1997) (refusing to find a taking where a homeowner was denied a setback variance for wetland regulations known by him to be in existence prior to his purchase of the property); Hunziker v. State, 519 N.W.2d 367, 371 (Iowa 1994) (“[T]he ‘bundle of rights’ the plaintiffs acquired by their fee simple title did not include the right to use the land contrary to the provision of those three Iowa Code sections. . . . These sections and their resulting prohibitions concerning the use of land ran—so to speak—with the land.”).
[97] See Lucas at 1019 n.8.
[98] See, e.g., Del Monte Dunes v. City of Monterey, 95 F.3d 1422, 1433 (9th Cir. 1996) (finding that since a sufficient number of people would buy the property for the restricted use it is “commercially marketable”), aff’d on other grounds, 119 S. Ct. 1624 (1999); Florida Rock Indus. v. United States, 18 F.3d 1560 (Fed. Cir. 1994) (finding that when determining fair market value a detailed inquiry into motivation and sophistication of buyers is not necessary).
[99]
Controls explicitly adopted to defer development on a temporary basis are
another possibility. The
well-known Ramapo case upheld a
growth management program that delayed development for up to eighteen
years, and authorized the approval of new development only when served by
adequate public facilities and services.
See Golden v. Ramapo Planning Bd., 285 N.E.2d 291, 302 (N.Y. 1972), appeal
dismissed, 409 U.S. 1003 (1972). The
town based its growth management plan on a comprehensive plan, and the New
York court relied on the plan in upholding these restrictions on development.
See id.
Moratoria and other controls that delay development temporarily are
now vulnerable under the Supreme Court’s recent takings cases as invalid
temporary takings. Some courts
since First English
have held that interim planning moratoria are not takings.
See, e.g., First English
Evangelical Church v. County of Los Angeles, 258 Cal. Rptr. 893 (Cal. Ct.
App. 1989) (holding that an interim ordinance was not a taking); Williams v.
City of Central, 907 P.2d 701 (Colo. Ct. App. 1995) (holding that a gaming
moratorium was not a taking absent extraordinary delay); Woodbury Place
Partners v. City of Woodbury, 492 N.W.2d 258 (Minn. Ct. App. 1992) (holding
that there was no taking in an adoption of a two-year moratorium).
However, although a delay in developing land outside a UGB may be temporary, the restriction on land that prevents development is not adopted as a temporary restriction. This fact may lead a court to hold, as it did in Tahoe-Sierra Preservation Council, 34 F. Supp. 2d at 1248-51, that the restriction is not the equivalent of a moratorium, and that a taking has occurred.
[100] See Boundary Drive Assocs. v. Shrewsbury Township Bd. of Supervisors, 491 A.2d 86, 90 (Pa. 1985). See also Agins v. City of Tiburon, 447 U.S. 255, 261 (1980) (refusing to find a compensable taking in California’s open-space plans).
[101] See Mandelker, supra note 95 , § 12.10. See, e.g., Still v. Board of County Comm’rs, 600 P.2d 433 (Or. Ct. App. 1979) (upholding rejection of non-farm development that violates agricultural preservation policy in exclusive agricultural zone even if economically unfeasible to farm land and no interference with farming in surrounding area).
[102] For examples of excellent treatises on the law of takings, see generally R. Meltz et al., The Takings Issue (1999) and Stephen J. Eagle, Regulatory Takings (1996).
[103] The Court in Lucas clearly indicated that regulations denying a property owner all “‘economically viable use of his land’” are per se takings. See Lucas v. South Carolina Coastal Council, 505 U.S. 1003, 1016-19 (1992) (quoting Agins, 447 U.S. at 260).
[104] See, e.g., K & K Constr., Inc. v. Department of Natural Resources, 575 N.W.2d 531, 535-38 (Mich. 1998) (holding that for a permit application where there was a single comprehensive development comprised of several tracts in common ownership, the parcel under consideration included those tracts).
[105] See, e.g., Bowles v. United States, 31 Fed. Cl. 37 (1994) (upholding a takings claim for denial of a permit for development of wetlands under the Clean Water Act, 33 U.S.C. §§ 1251-1387 (1994)).
[106] Support can be found for this position in Justice Brennan’s opinion in Penn Central, although it was not fully developed. See generally Penn Cent. Transp. Co. v. New York City, 438 U.S. 104 (1978). See also Daniel R. Mandelker, Waiving the Taking Clause: Conflicting Signals from the Supreme Court, in 1994 Proceedings of the Institute on Planning, Zoning, and Eminent Domain 57 (Southwestern Legal Foundation ed., 1995) (noting the convoluted nature of takings jurisprudence).
[107] See Norbeck Village Joint Venture v. Montgomery County Council, 254 A.2d 700 (Md. 1969). It should be noted that in this author’s opinion the Maryland courts are more receptive than most to local government land use regulations.
[108]
See id. at 703.
[109]
See id. at 703-04.
[110] The court held that the landowner “did not, by an Olney plan country mile, meet their heavy burden of showing that the rezoning they dispute confiscates their property.” Id. at 706.
[111] See Security Management Corp. v. Baltimore County, 655 A.2d 1326, 1328 (Md. Ct. App.). The court also rejected equal protection and due process claims. See id. at 1330-33.
[112]
See id. at 1329.
[113] See id. at 1330. The county council had rejected a rezoning to 16 dwelling units to the acre in what the developer called an “environmentally sensitive” community.
[114] One commentator has suggested clustering techniques for developments in large lots that can leave room for future infill development when a UGB expands. See Easley, supra note 13 , at 14. How effective this technique can be is problematic.
[115] The courts have upheld zoning for up to five-acre lots when necessary because of environmental conditions. See Mandelker, supra note 95 , § 5.26.
[116] See Julian Conrad Juergensmeyer et al., Transfer of Development Rights After Suitum, 30 Urb. Law. 44l, 444-48 (1998).
[117]
See id. at 444-46.
[118] See Pruetz, supra note 24 , at 210-14.
[119] See Barry C. Field & Jon M. Conrad, Economic Issues in Programs of Transferable Development Right, 51 Land Econ. 331, 338 (1975).
[120] See Sarah J. Stevenson, Note, Banking on TDRs: The Government’s Role as Banker of Transferable Development Rights, 73 N.Y.U. L. Rev. 1329, 1371 (1998).
[121] See Mandelker, supra note 95 , §§ 6.27-6.30.
[122] I am indebted to Ed Sullivan for these suggestions.
[123] There may be legal problems in levying impact fees in established neighborhoods if the municipality does not have the authority to levy these fees in connection with the issuance of a building permit or other development approval, such as a conditional use. See, e.g., Bringle v. Board of Supervisors, 351 P.2d 765 (Cal. 1960) (holding that a zoning board had implied power to attach condition requiring dedication of land). The opportunity to levy fees as part of subdivision approval does not usually exist because inner city areas are built-up.
[124] The plan for King County in Seattle, Washington is an example. See Douglas R. Porter, Profiles in Growth Management 230-55 (1996).
[125] See Mandelker, supra note 95 , §§ 6.32-6.34.
[126]
Id.
[127] See id. § 201.1(6)(a).
[128] See, e.g., Dolan v. City of Tigard, 512 U.S. 374 (1994) (requiring that government’s permit condition does not impose more than a proportionate degree of burden on the landowner).
[129] See Porter, supra note 13, at 122-133.
[130]
See S. Meck, Model Statutes on
Uniform Development Standards, Concurrency and Smart Growth Technical
Assistance (Apr. 19, 1999) (draft on file with author);
Porter, supra note 13, at 131. See
e.g., Fla. Dept. of Transp., Report of Transportation and Land Use Study
Committee 19-32 (1999) (on file with author). The concurrency requirement, as stated in Florida
legislation, is intended to provide “that public facilities and services
needed to support development shall be available concurrent with the
impacts of such development.” Fla. Stat. Ann. § 163.3177(10)(h) (West 1999).
In Florida, the concurrency requirement has tended to force new
development to the urban fringe, where service levels are higher.
See
Fla. Dept. of Transp., supra.