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<br />smaller, shallower roots that extend far
<br />
<br />beyond the drip line.
<br />
<br />Maintenance'after development. Once
<br />
<br />development is complete, the next step in the
<br />
<br />tree preservation proc.ess is continuing main-
<br />
<br />tenance, ensuring that trees protected by the
<br />
<br />local ordinance survive' and flourish. This may
<br />
<br />entail replacement of protected trees that die
<br />
<br />after construction is completed or requiring
<br />
<br />periodic fertilizing and pruning until their sur-
<br />
<br />vival is assured. Other ordinances require pro-
<br />
<br />tected and replacement trees to be main.
<br />
<br />tained in a healthy condition with proper
<br />
<br />fertilization, pruning, and irrigation as neces-
<br />
<br />sary for a prescribed period.
<br />
<br />While the number of ordinances that deal
<br />
<br />with the tail end of the development process is
<br />
<br />relatively small, more communities are recogniz-
<br />
<br />ing that modest measures at this point are
<br />
<br />important supplements. The ordinances that do
<br />
<br />address this issue are instructive. The require-
<br />
<br />ments of the tree protection ordinance in
<br />
<br />Columbia, Missouri, are fairly typical:
<br />
<br />If any of the trees required to be retaiQed or
<br />trees planted as part of the landscaping
<br />plan should die within a period of eighteen
<br />(18) months.after completion of the activi-
<br />ties associated with the land disturbance
<br />permit. the owner of the property shall
<br />replace the trees within six (6) months at a
<br />ratio of one-to-one with an approved tree
<br />having a minimum diameter of two (2)
<br />inches measured at a point one foot above
<br />natural grade. Shrubbery or other plantings
<br />which die within eighteen (18) months of
<br />completion of the activities shall be
<br />replaced in kind within six (6) months.
<br />
<br />Given the fact that it takes at least one
<br />growing season and typically three years or
<br />longer for a tree to show signs of stress and
<br />die after construction nearby, 18 months
<br />would be a minimum replacement period.
<br />
<br />EMERGING ISSUES
<br />Tree protection ordinances continue to mature
<br />and become more sophisticated as local gov-
<br />ernments gain experience with their regula.
<br />tions and face new issues and challenges.
<br />Existing single-family homes/lots. In the
<br />past, a majority of communities simply
<br />exempted development on existing residential
<br />lots from having to comply with tree protec-
<br />tion regulations. Thus, homeowners of exist-
<br />ing houses were not required to seek ~ermits
<br />to remove a tree. However, as communities
<br />come to recbgnize the value of trees in exist-
<br />ing neighborhoods, more are requiring owners
<br />of existing single.family houses to seek
<br />
<br />removal permits, especially for larger trees.
<br />For example, in its new development code,
<br />Franklin, Tennessee, a fast-growing suburb of
<br />Nashville, has included strong vegetation pro.
<br />tection regulations that make no exemptions
<br />for existing lots and houses.
<br />lnfill and redevelapment apportunities.
<br />Smart growth policies and limited land avail.
<br />ability have encouraged many communities to
<br />adopt policies to promote infill and redevelop-
<br />ment. This type of development frequently
<br />takes place on smaller, constrained lots where
<br />strict, inflexible. tree preservation regulations
<br />could stifle construction. Therefore, savvy
<br />communities like Clayton, Missouri, allow
<br />removal of trees if development would be
<br />unduly thwarted, but requ.ire inch.for-inch on-
<br />or off.site mitigation or the option of in-lieu
<br />payments into a local tree fund.
<br />Carbon budgets. In the face of federal
<br />inaction, an increasing number of local gov-
<br />ernments are taking an active approach to
<br />issues of global warming and climate change
<br />that involve trees. As trees grow they naturally
<br />remove carbon dioxide (C02) from the atmos-
<br />phere through a process called photosynthe-
<br />sis. CO2 is emitted into the atmosphere
<br />through activities such as driving, operating
<br />fossil.fuel power plants, heating or cooling a
<br />home, etc. While CO2 has the potential to
<br />remain in the atmosphere for years, tree
<br />leaves can remove some CO2 and store the
<br />carbon in their biomass. Given this, large-
<br />scale tree planting and protection efforts are
<br />seen as a legitimate tool for effectively
<br />addressing air quality.
<br />Some cities are adopting ambitious tree
<br />planting programs. Portland, Oregon, for exam-
<br />ple, has planted over 750,000 trees and shrubs
<br />since 1996. Seattle has committed to restoring
<br />2,500 acres of urban forests by the year 2024.
<br />Chicago has taken a slightly different approach
<br />by initiating the "Chicago Climate Exchange"-
<br />the world's first legally binding, multisectoral,
<br />rule-based, and integrated greenhouse gas emis.
<br />sion registry, carbon reduction, and trading sys-
<br />tem. This program holds companies responsible
<br />for the amount of carbon emissions they produce
<br />and allows these emissions to be offset by other
<br />carbon-mitigating projects. including reforesta-
<br />tion. For example, in May 2006, an Indiana farm
<br />enrolled as an offset provider in the Chicago
<br />Climate Exchange. One.third of this 604-acre
<br />family-owned farm is dedicated to hardwood
<br />trees, including black walnuts. Based on the
<br />farm's management practices, tree age. tree den-
<br />sity, and other factors. it is estimated that the
<br />
<br />farm will remove about 3,400 metric tons of car-
<br />bon from the atmosphere. This translates into
<br />carbon credits, which are currently traded on the
<br />exchange system. Those companies that have
<br />pledged to reduce their CO2 emissions, including
<br />Ford, American Electric Power, and .IBM, now
<br />have the ability to partner with this farm and pur.
<br />chase its carbon credits as a means of achieving
<br />their CO2 reduction goals.
<br />The next wave we can expectto see atthe
<br />local level regarding carbon budgets will draw
<br />.on precedents from European cities that require
<br />any additional carbon dioxide emissions associ-
<br />ated with a development project (e.g., from
<br />increased traffic) be offset by tree protection or
<br />tree planting both on. and off-site.
<br />
<br />CONCLUSION
<br />The growing concerns over global warming and
<br />climate change, coupled with the increasing evi.
<br />dence of the aesthetic and economic benefits of
<br />tree protection, promise to usher in a whole
<br />new era of community tree protection efforts.
<br />Drawing on practical experience from first- and
<br />second-generation ordinances from around the
<br />country and with careful attention to legal
<br />issues, local governments can craft tree protec-
<br />tion ordinances designed for the 21st century
<br />that will be effective and fair.
<br />
<br />.~~~~~[~~~~~~~~~:;/i':~~1:~~~~i~
<br />
<br />VOL. 23, NO.7
<br />Zoning Practice is a monthly publication of the
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