Urban Forests Help Environment, Report Says
Urban Trees Manage Stormwater, Remove Pollution
The urban forests along Colorado's Front Range act
like a regional stormwater management system, clean millions of
pounds of pollutants from the air and offer homeowners millions of
dollars in cooling costs savings each year, according to a new report.
The report by American Forests lists these benefits: the urban
trees in the seven largest northern Front Range communities combine
to act like a $44 million stormwater management system and remove
2.2 million pounds of pollutants annually -- including ozone, carbon
monoxide and fine sooty particles.
The cooling shade that trees cast also saves homeowners an
estimated $4.5 million in annual air conditioning costs, or about
$50 per household. This, in turn, prevents the emission of 1.6
million tons of carbon gases from power plants, the group
estimated.
But the study, based on a comparison of satellite photos taken
in 1986 and 1998 (pictured, left), also suggests that the growth of the region's
urban forests isn't keeping pace with galloping development of
impervious surfaces such as roofs, driveways and parking lots, and
newly planted subdivisions.
The report seeks to impress on city managers and decisionmakers
that trees are more than just something good to look at.
"Air filter, sponge, humidifier, heat shield, wind block, carbon
sink: trees are the ultimate urban multitaskers," said Gary Moll,
vice president of American Forests' Urban Forest Center.
"We want people to understand that trees are an important part
of the city infrastructure," he said. "There's a hard part, and
there's a green part, and we should be planning for both."
Local officials acknowledge that the ecosystem values cited in
the report are just estimates. The study was based on findings from
39 representative plots, which were then extrapolated.
Denver's urban forester thinks the report is right "on the money."
"Finally, we have a way to quantify the benefits that trees
provide," said Jude O'Connor. "We can give them a dollar value,
not just say that they're `nice' and they soften hard edges of the
urban landscape."
The report shows that in Denver, Westminster, Lakewood and
Aurora, the amount of land covered by impervious, or
water-shedding, surfaces grew from 125,500 acres to 166,000 acres,
a gain of 32 percent. By contrast, forested areas grew nearly 45
percent, from 18,000 acres to 26,000 acres.
But even with that jump, trees covered a mere 6 percent of the
four cities' total acreage, while 39 percent has been paved over.
O'Connor, who must care for 200,000 city trees with only 25
staffers and a budget of $2.5 million, said the report helps to
demonstrate that urban forest management has to be looked at as an
ongoing process.
"Many trees in our older neighborhoods are overmature and
declining," she said. "Eventually, they'll have to come out, but
the key piece is to get back in there and replant."
Additional Resources:
The report by American Forests lists these benefits: the urban
trees in the seven largest northern Front Range communities combine
to act like a $44 million stormwater management system and remove
2.2 million pounds of pollutants annually -- including ozone, carbon
monoxide and fine sooty particles.
The cooling shade that trees cast also saves homeowners an
estimated $4.5 million in annual air conditioning costs, or about
$50 per household. This, in turn, prevents the emission of 1.6
million tons of carbon gases from power plants, the group
estimated.
But the study, based on a comparison of satellite photos taken
in 1986 and 1998 (pictured, left), also suggests that the growth of the region's
urban forests isn't keeping pace with galloping development of
impervious surfaces such as roofs, driveways and parking lots, and
newly planted subdivisions.
The report seeks to impress on city managers and decisionmakers
that trees are more than just something good to look at.
"Air filter, sponge, humidifier, heat shield, wind block, carbon
sink: trees are the ultimate urban multitaskers," said Gary Moll,
vice president of American Forests' Urban Forest Center.
"We want people to understand that trees are an important part
of the city infrastructure," he said. "There's a hard part, and
there's a green part, and we should be planning for both."
Local officials acknowledge that the ecosystem values cited in
the report are just estimates. The study was based on findings from
39 representative plots, which were then extrapolated.
Denver's urban forester thinks the report is right "on the money."
"Finally, we have a way to quantify the benefits that trees
provide," said Jude O'Connor. "We can give them a dollar value,
not just say that they're `nice' and they soften hard edges of the
urban landscape."
The report shows that in Denver, Westminster, Lakewood and
Aurora, the amount of land covered by impervious, or
water-shedding, surfaces grew from 125,500 acres to 166,000 acres,
a gain of 32 percent. By contrast, forested areas grew nearly 45
percent, from 18,000 acres to 26,000 acres.
But even with that jump, trees covered a mere 6 percent of the
four cities' total acreage, while 39 percent has been paved over.
O'Connor, who must care for 200,000 city trees with only 25
staffers and a budget of $2.5 million, said the report helps to
demonstrate that urban forest management has to be looked at as an
ongoing process.
"Many trees in our older neighborhoods are overmature and
declining," she said. "Eventually, they'll have to come out, but
the key piece is to get back in there and replant."
Copyright 2002 by TheDenverChannel.com. The Associated Press contributed to this report. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
