Changing a city from gray back to green requires computer savvy, high-tech picutes, and local action.

BY COURTNEY LEATHERMAN
When Sheila Hogan wants to tell the story of the decline of trees in Washington, DC, she stops talking and starts showing old black and white photos. The glossies, taken in the 1930s, 40s, and 50s, show the city's main arteries like K Street and East Capitol Street lined with statuesque American elms; their vase-shaped, expansive canopies shading the streets.

Hogan, executive director of the Casey Trees Endowment Fund, doesn't need recent photos to illustrate the contrast today. Local residents and politicians know the images in those old photos are a far cry from the picture along those same city streets today, where 10-foot Japanese zelkovas and Shademaster honeylocust struggle for survival in planter boxes imbedded in brick sidewalks. Along some streets, there are no trees at all.

Photos can help make some people pay attention to a city's "tree deficit"; they can even inspire activism. But they don't do much for municipal planners who need more than nostalgia to prepare for the future.

While more and more policymakers and planners have come to understand the environmental and economic benefits trees provide in terms of stormwater management, air quality, and energy conservation-and as state and federal regulators develop tougher standards in all these areas-what planners need now are tools to map out the urban forest and to incorporate that "green infrastructure" into their thinking.

After all, it's easy for planners to figure out where sewer lines are laid, power lines are run, and manholes placed: The planners just check out a computer database that maps the location of those various components through technology called Geographic Information Systems (GIS). What's hard is figuring out where the trees are planted.

And that's where American Forests believes it can help cities. With support from the U.S. Forest Service and the use of new high-resolution satellite imagery, American Forests is working on high-tech mapping of individual trees. Its first project, which will be presented at the 2001 National Urban Forest Conference September 5-8, focuses on the Washington metropolitan region with the idea that it could serve as a model for cities and regions around the country.

An earlier study that detailed the District's declining tree cover helped prompt Betty Brown Casey's $50 million endowment to reforest the city. The Casey Trees Endowment Fund is helping to fund the current DC analysis.