People's Preferences for Greenway Landscapes:
Survey Ratings of Indianapolis Trails
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People's Preferences for Greenway Landscapes: Survey Ratings of Indianapolis Trails
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| 1. What is an Urban Forest?2. What Benefits Does an Urban Forest Offer?Reduction in Stormwater Runoff Increase in Recreational Opportunities Improvement in Health and Well-being 3. How is it Managed?4. How Do Greenways Fit In?What is an Urban Forest?
The urban forest exists within
many scales, locations, and owners.
Specifically, it can be defined as, “…the sum of all woody and
associated vegetation in and around dense human settlements…” (Miller,
1997). It
is the sum of park trees, street trees, residential trees, as well as riparian
vegetation. It
includes trees on unused property, trees in utility rights-of-way and
transportation corridors.
Trees within an urban forest contain a complex array of public, private,
and quasi-public owners: local government agencies, private landowners, public
institutions, etc.
According
to Miller (1997), three things dictate the configuration of the urban forest:
urban morphology, natural factors, and management.
Urban morphology is the structure of the city as dictated by land use,
and outlines the areas where trees can grow.
Natural factors, such as soil, water, and sunlight dictate the types of
vegetation that will grow, as well as the location.
Management influences the urban forests by dictating the “species and
ecosystems” (Miller, 1997) that people decide to incorporate in the
surrounding landscape. American Forests, a non-profit organization dedicated to planting trees for restoration and the practice of urban forestry, recommends these canopy levels according to land use (American Forests, 2001):
Although this may seem like a lofty goal, with an urban forestry program that is
effectively implemented and monitored as well as with the help of local
volunteer organizations, it is certainly an attainable goal. Several organizations across the U.S. provide information regarding urban forestry:
[Top] What Benefits Does an Urban Forest Offer? There
are many reasons why an urban forest is important to a community.
It provides many economic, aesthetic, environmental, community, and
health benefits. Table 1 identifies
the major direct and indirect benefits that an urban forest provides.
A description of these benefits follows, and when possible, monetary
quantifications of the benefits the urban forest provides are given.
[Top]
Increased Property Values
According to the University of Connecticut Cooperative Extension Forestry
service (UCCEF, 2001), a healthy, mature street tree has an average value of
$2064. Property
values are increased by 15-20% when homes are surrounded by large trees or are
located on well-shaded streets.
Furthermore, the value of trees and the urban forest appreciates over
time, which provides an important economic asset to a municipality. Decreased Energy Use
A mature tree transpires up
to 100 gallons of water a day, which is equivalent to five large air
conditioners operating 20 hours a day, resulting in temperature decreases of
5-12 degrees. Shade
trees can also reduce temperature on building surfaces by 16 degrees, which cuts
air conditioner costs.
Both of these factors are useful in mitigating the heat island effect
that afflicts urban areas.
Furthermore, windbreaks formed by trees can reduce heating costs in
winter by 20%-30% (UCCEF, 2001). [Top] Improvement in Air QualityAn urban forest is very effective at improving air quality. Consider these statistics from the University of Connecticut Cooperative Extension of Forestry (UCCEF, 2001):
Reduction in Stormwater Runoff
An urban forest reduces runoff by slowing stormwater down so it can infiltrate
into the soil and also by keeping the soil aerated to allow greater percolation
of water. A
reduction in runoff can be especially important in an urban area that has a
large amount of impervious space. Decrease in Soil Erosion
Trees decrease soil erosion in a couple of ways.
First, their roots serve to anchor the soil, which helps to mitigate the
erosive effects of wind and water.
The tree canopy also serves to intercept water during storms, so less
water is hitting the ground’s surface and with less force.
It has been estimated that over a 50-year lifetime, one tree controls
$31,250 worth of soil erosion (UCCEF, 2001). Improvement in Water Quality
An urban forest improves water quality in a variety of ways.
First, it reduces stormwater runoff that can carry numerous pollutants as
well as large amounts of sediment to water bodies.
It also reduces the amount of soil erosion and sedimentation that will be
carried in runoff.
It is estimated that over a 50-year lifetime, a tree recycles $37,500
worth of water (UCCEF, 2001). Creation of Wildlife Habitat
Urban areas usually do not
contain large areas suitable for natural habitats and furthermore, development
creates habitat fragmentation.
However, an urban forest can house many creatures such as birds and
squirrels that do not need large areas to survive.
Increase in Community Pride
Trees add beauty to
urban areas. Community
residents take pride in the fact that their city is an attractive place to live
as well as to visit. Increase in Recreational Opportunities
Large tracts of urban forest
such as parks can create ideal places for residents and visitors to relax and
spend some time outside.
The urban forest presents a myriad of recreational activities such as
bird watching, sports, and hiking. Improvement in Health and Well-being
Urban forests can
directly and indirectly improve the health and well-being of the community’s
residents. This
occurs indirectly through the improvement of air and water quality.
Furthermore, studies have shown that hospital patients recuperate better
if they can see trees from their recovery room windows (UCCEF, 2001).
Overall, the presence of trees can improve the quality of life for city
residents. Reduction of noise levels
According to some studies, tree
buffers can reduce unwanted noise by up to 50% (UCCEF, 2001).
Due to the increased density and mix of uses in a city, this can be very
important to improving the quality of life for residents. [Top] How is it Managed?
The USDA Forest Service (1990) describes management of the urban forest
as “…the planning for and management of a community’s forest resources to
enhance the quality of life. The
process integrates the economic, environmental, political, and social values of
the community to develop a comprehensive management plan for the urban
forest.” Due to the
integration of a variety of public and private entities’ economic, political,
and social values, management of the urban forest is a complex issue.
Many different public and private entities control the fate of the urban
forest. These range from federal,
state, and local governments to private landowners. Getting all of these entities to work together to improve the
urban forest is a large, complex issue for an urban forest program.
Appendix One contains a partial list of possible players within this
context.
Only
an average of 10% of the urban forest exists on public land (Moll & Kollin,
1993). The remainder exists on private land in the form of
residential lots, wood lots, industrial sites, corporate parks, etc.
Their management is in the hands of a commercial arborist, landscape
architect, contractor or other professionals, or these areas are not managed at
all. This is the dilemma facing an
urban forestry program: how can these individual, private areas be incorporated
within the management program and public framework?
[Top] How Do Greenways Fit In?Greenways are often utilized as part of an urban forestry program to conserve valuable natural habitats. They offer two main benefits:
Pressure from development is often the main culprit in habitat fragmentation and loss in an urban forest. The absolute loss of urban forest land is an imperative problem that needs to be addressed, but fragmentation also creates several negative environmental effects that need to be addressed. For instance (Smith & Cawood, 1993):
Due to their linear nature, greenways can provide the best tool to mitigate habitat fragmentation by connecting patches of existing urban forest areas together. [Top] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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People's Preferences for Greenway Landscapes: Survey Ratings of Indianapolis Trails http://www.trailsurvey.urbancenter.iupui.edu
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