The greenery gap
Wednesday, October 11, 2006
A not-for-profit group says many American cities don't have enough trees.
Tree cover in Cape Girardeau depends on the neighborhood. Some neighborhoods, like the ones along Lorimier Street, have lush, leafy corridors. Other, newer subdivisions, like Arbor Heights, have barely a tree in sight.
Neighborhoods like the latter are what concern American Forests, a Washington, D.C.-based not-for-profit organization that tracks tree cover in urban areas.
In a recent study the organization recommended a minimum 40 percent tree coverage in city centers and suburbs east of the Mississippi. That, experts say, is the minimum needed to combat urban areas' rain runoff, pollution and overheating problems.
An American Forests representative said Cape Girardeau would likely require close to the 40 percent figure. That's about twice the city's current tree coverage.
The organization has determined that most cities don't measure up. For example, San Diego, a city of more than 1.2 million, has only 13 percent tree cover, according to analysis of satellite imagery. Tree coverage in all the urban areas American Forests studied has decreased by 30 percent over the past 20 years.
All in all, the organization determined the 448 largest urban areas in the United States lost 3.5 billion trees in the last 10 years.
Accurately determining the percentage of Cape Girardeau with tree cover is not simple. It relies heavily on image analysis of a computerized tree cover survey conducted in 1989. The survey was part of a $180,000 topographical mapping project and used aerial photography.
By looking at this survey and estimating the number of trees leveled in the past 17 years, the city's senior Geographic Information Systems technician, Rich Daume, estimated Cape Girardeau has between 20 and 25 percent tree coverage.
He says that's not bad. "I think Cape has a lot of trees. I mean, look out, you see shade most places you go."
Some, though, disagree. They say they've seen recent indications that trees are not a priority for Cape Girardeau, which has held the title of Tree City USA for seven years.
"You've got to understand that all the recent concerns about flooding are entirely a consequence of removing trees and grassland and turning it into tarmac and concrete," said Alan Journet, a biology professor at Southeast Missouri State University. "It's just a shame the planning and zoning folks don't understand that."
Journet pointed particularly to U.S. 61 leading to Jackson as lacking any sort of green space to slow down runoff. "I'm not against progress, but I think nobody in the community as a whole is talking about the costs of development," he said.
Gary Moll, vice president of American Forests' Ecosystem Center, says runoff control is a rarely considered consequence of deforestation in urban areas.
"When we added up the cost of keeping tree cover versus the cost of not having it and putting in the extra storm water mechanisms, we saw that it's not even close. Tree cover in urban areas is a very good investment," he said. "Adequate tree cover does as good a job or better than retention basins and all the other mechanisms."
Moll added that trees and grassland slow down runoff and help filter out potential contaminants before the runoff enters streams and other water sources.
American Forests found that 100 mature trees capture about 250,000 gallons of rainwater per year. San Antonio, Texas, for example, plans a movement to increase its city tree coverage from 27 percent to 35 percent. City officials hope this move will help them avoid spending $200 million on a new storm water facility.
Unlike many Missouri cities, including Columbia, Maryville and Springfield, Cape Girardeau has no green space requirement.
Skip Smallwood, chairman of the planning and zoning commission, says trees are not generally a top priority for commissioners. "The only time we look seriously at green space is if a buffer is considered," he said. "There can be concerns about possible encroachment and the vicinity of a development to neighboring properties and so we'll ask for trees, bushes or fences, but as far as enforcing green spaces, we don't do it."
Smallwood added that green space is something commissioners are interested in looking at when the city's comprehensive plan is revised in 2007.
Urban forester Rocky Hayes of the Missouri Department of Conservation called Cape Girardeau's tree coverage "hit and miss."
"Today with a lot of the new subdivision developers, if there's already trees on the site, there are very few when they get done," he said. "That seems to be the trend today, to level the site and get maximum amount of houses in there."
Hayes said he believes Cape Girardeau's tree coverage is fairly similar to other Missouri cities and the impetus is largely on homeowners to plant and maintain trees if they are desired.
Dan Muser is the director of the Cape Girardeau Tree Advisory Board. The board votes on when to take down trees on public property. Muser said his board tries to save trees whenever possible but must take into account the health of the tree, interference with sidewalks or foundations and city progress plans.
Even so, sometimes the board must make decisions that upset people. This was the case over the summer, when the city removed about 40 trees along Mount Auburn Road to allow a widening project to go forward.
"With that one we had no choice," Muser said. "We either decided not to do the project or remove the trees. ... It was a pretty simple decision, actually."
But even though most agree the project will be a big help, some miss the trees. "I was pretty disappointed when they were taken down," said Geraldine Bohnsack, who works as a receptionist at 23 Doctors' Park. "They were just starting to take off and grow and they made the parking lot more pleasant and prettier, but I guess that's progress."
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