March 2013 - Parks & Recreation - 55

nagey says. " It is good to have a detailed
understanding of your urban forest
through an actual inventory that does
go through tree by tree-that's really important from a management and maintenance perspective-but that cover benchmark is really important for planning
for the future and for communicating to
your public the value of trees. "
Money Does Grow on Trees
Although most people inherently understand the benefits that trees bring
to communities, i-Tree enables users to
quantify and maximize those benefits.
" Most cities are going toward the
canopy-cover approach to urban
tree management, " Carnagey says.
" Rather than just looking at just
the trees in your forest and tracking
those, you're looking at the overall
coverage, mainly because of the benefits that you can start to see from
looking at the canopy cover in aggregate. There are all sorts of environmental benefits that you get, but also
environmental services, like stormwater control and carbon sequestration. You can start to get a sense
of what sort of savings in services
you're getting from the canopy cover
once you know what the percentages
are for your city. "
Using the National Tree Benefits
Calculator (www.treebenefits.com),
an analysis indicated that Albany's
urban forest intercepts 465 million
gallons of stormwater every year, providing an essential service valued at
$12.9 million annually. Carnagey estimates that each one-percent increase
in tree-canopy coverage will require
planting 5,400 shade trees, which
would add $716,000 worth of annual
stormwater capacity. Even though the
trees will take decades to mature, the
eventual return on investment far outstrips the cost.

Back in arid Boise, Jorgenson notes
that their initial tree-canopy assessment was driven more by air-quality
issues than stormwater-management
concerns. The Treasure Valley area
of Idaho, where Boise is located,
is approaching its air-quality limits
for ozone, and particulate matter
is also high. In response, the Idaho Department of Environmental
Quality began to build a coalition
of organizations that would benefit
from more information on the area's
tree-canopy coverage. The Treasure
Valley tree-canopy assessment was
funded by a USDA grant in cooperation with the Idaho Department
of Lands, local communities, the
Idaho Department of Environmental Quality, Idaho Power, Boise
State University, and several other
partners.

An aerial view with GIS layer shows
the location of Albany's inventoried
trees.

" From having this information, we
know what the benefits of trees are,
and it needs to be considered as part
of the solution, " Jorgenson says. " Not
that planting trees is going to solve the
world's problems-we all know that's
not the case-it's just another piece in
the puzzle, another tool we can use to
help control our air quality. "
Growing Your Canopy
i-Tree also features a new design tool
that can help assess the benefits of
trees down to an individual parcel
of property. Using Google Maps, the
tool allows users to see how tree selection, size, and placement will affect
heating and cooling energy use as well

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Parks & Recreation

March 2013 - Parks & Recreation

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