March 2013 - Parks & Recreation - 54

Operations
images from Google Maps.
" We've had the idea for more than
10 years since I've been here and, honestly, I think the technology is finally
catching up to our desires on this, "
Jorgenson says. " We can get down to
where we can look at an entire city
and determine what your percentage
of tree canopy coverage is and even
identify down to specific planting sites
where you have room for more trees. "
Boise, situated in a desert, has only
about 15 percent tree-canopy coverage, but that overall figure is somewhat misleading, according to Jorgenson.
" Boise has undergone a huge
growth explosion in the last 20 or 30
years, " Jorgenson explains. " In the
older parts-Boise's north end-we're
looking at 30 to 40 percent tree canopy down there, but the city as a whole
drops it down to 15 percent. So if you
leave those old neighborhoods out,
where are you at? Probably only 6 to
10 percent for the rest of the city. So
that will help us determine where we
want to see additional growth in the
tree canopy. "

i-Tree
Ecosystem Analysis
City of Albany

Urban Forest Effects and Values
June 2012

Last summer, a report revealed that
Albany's trees provided $12.9 million
worth of stormwater capacity.

Often a tree-canopy analysis is performed on several neighboring communities at the same time. In the Willamette Valley in Oregon, an American
Forests tree-canopy analysis in 2001
of the entire valley, including Albany, Corvallis, Salem, and Portland,

revealed that the valley's tree canopy
declined from 42 percent to 24 percent
from 1972 to 2000. American Forests
recommends a tree-canopy cover of
40 percent for urban areas in the Willamette Valley and lower Columbia
River, but Albany's current canopy
cover falls well short of that level, so
the city needed to set a more realistic
goal.
" The goal is 25 percent canopy
cover-right now, we have 18 percent, " says Craig Carnagey, parks
and facilities manager for the City
of Albany. " Twenty-five percent
seems to be a reasonable amount of
cover based on historic coverage....
Plus, when you calculate in the environmental services, it seemed like
you would really be maxing out your
benefits from the canopy cover if it
were around 25 percent. "
In 2005, the city hired a contractor
to enter tree inventory data points
into ArborPro, a GIS software program. Bringing in a contractor enabled the detailed tree inventory to
be completed in just one summer
month, rather than relying on volunteers and interns over a longer period.
Now Carnagey can pull up any tree
in the inventory database and see its
species, size, condition, maintenance
history, and even its photo in many
cases. And, following up on the 2001
satellite canopy analysis, last summer
a graduate student performed a more
detailed i-Tree canopy analysis by
recording tree cover at 190 random
sampling sites in Albany. Carnagey
notes that the tree inventory and canopy analysis are both useful tools.
" I think the i-Tree set of software is a
really good tool to start out with, " CarAlbany's tree inventory system
includes data such as species,
age, condition, structure, and a
maintenance log.

Parks & Recreation

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March 2013 - Parks & Recreation

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