Blue skies are fine, but urban forester Jay Banks looks forward to the day that the skies of Leesburg, VA, look a lot greener.

In November, Leesburg became the first town in Virginia and the seventh in the Bay watershed to become an official partner in reaching the Chesapeake Bay Program urban tree canopy goal.

“My personal hope is that trees start to be considered as an asset to the community, instead of a liability,” Banks said. “Once that happens, we’ve turned a corner.”

The state-federal Bay Program announced the tree canopy goal in a 2003, as part of a directive that focused mainly on restoring forested areas along streams and rivers. But the directive also emphasized increased tree canopy in developed areas—calling for specific canopy goals to be set for 15 cities—where few opportunities exist for restoring streamside buffers to the recommended width.

“Some locations for trees matter more than others—like along streams, where trees provide the most benefits,” said Sally Claggett, the U.S. Forest Service liaison to the Bay Program. “But in an urban area, they all matter. Every tree is a well-placed tree because it’s near a roof top or sidewalk, where it catches the runoff from those impervious surfaces.”

Tree canopy is the layer of leaves and branches that cover the ground when viewed from above.

In urban and developing communities, trees are often viewed as little more than problems to be maintained or removed. Fallen limbs and trees can damage property and obstruct roads. Leaves need to be raked and entire trees must be felled to make room for new buildings.

But advocates for urban trees, and trees in general, say that the benefits outweigh the perceived problems.

The canopy intercepts and absorbs rainwater, reducing the amount that careens through streets and gutters as stormwater runoff, and their roots filter pollutants such as nutrients, while stabilizing sediment. The trees store carbon, reducing the amount in the atmosphere that would otherwise contribute to global warming. They also support wildlife habitat as well as provide shelter for birds and cooler streams for fish.

Urban trees do a lot for human habitat, too. “The State of Chesapeake Forests,” a report recently produced by the Forest Service and The Conservation Fund, noted that urban tree canopy in 2000 absorbed more than 500 metric tons of air pollution in Baltimore and nearly 400 metric tons in Washington, D.C.

Properly placed trees also save energy by cooling buildings in the summer and keeping them warm in winter, the report said. Homes with shade often have energy costs that are 20 to 25 percent lower than those without.

“There is money in trees, literally,” Claggett said. “There are cost reductions in heating and cooling, evidence that people shop more on tree-lined streets, and houses can be worth up to 30 percent more if they have mature vegetation.”

An analysis by the conservation group American Forests estimated that Leesburg—located in a rapidly developed section of Northern Virginia—lost 71 percent of its urban tree canopy between 1992 and 2001. With it, the city lost stormwater management and air pollution reduction services valued at nearly $9 million.

“Ironically, right on the heels of that report, the city approved a budget of almost $8 million for stormwater projects to control flooding,” Banks said. “So people are beginning to realize that trees need to be a part of the big picture.”

The 2003 directive commits Maryland, Pennsylvania and Virginia to each partner with at least five communities that want to set and pursue a specific goal for increased tree canopy in developed areas. The partner communities set the goals, and the numbers vary with the setting.

In Pennsylvania, the inaugural partner is the town of Columbia, located along the Susquehanna River. In Maryland, the roster includes the cities of Annapolis, Baltimore, Cumberland, Hyattsville and Rockville, and Baltimore County.

“The mayor and/or the council of each community has signed a letter of commitment to participate in the process,” said Mike Galvin, urban and community forester for the Maryland Department of Natural Resources and member of the Bay Program Forestry Workgroup. “The local officials have been very supportive. They want to help their communities and help the Bay.”

Four of the communities adopted specific goals this year—and aimed high. American Forests recommends that towns and cities cover 40 percent of their area with tree canopy. Baltimore, the first to adopt a specific goal, has aggressive plans to meet the recommendation by doubling its canopy coverage from 20 percent to 40 percent by 2036. Leesburg, beginning with approximately 8 percent coverage, has also set a 40 percent goal.

Two others aim to surpass that mark. Annapolis, at 41 percent coverage, and Columbia, with 37 percent coverage in the town core, both hope to reach 50 percent by 2036.

Cumberland, Hyattsville, Rockville and Baltimore County are assessing existing canopy cover and will set goals in the near future.

Assessments include aerial photography and satellite images, mixed with computerized mapping and some ground surveys. Much of the process was developed and refined in Baltimore, through work by the Forest Service and University of Vermont.

“We looked at a high-resolution satellite image of a jurisdiction, then assessed how much vegetation is within the boundaries and how much of that vegetation is tree canopy,” Galvin said. “It’s like looking at a cookie cutter and asking how much of it is filled with trees and how much isn’t.”

The technology allows local officials to extract a range of detailed information, including potential locations for more trees. Galvin said this prevents goals from being arbitrary numbers and provides a reality check.

“The Forest Service tools showed us that most of the existing trees and opportunities for trees are on private land,” Galvin said. “If the city covered public land completely in trees, you probably still wouldn’t achieve the goal.”

As a result, communities will not only keep urban trees on the planning table, but also explore incentives for businesses, institutions and residential landowners to plant and maintain trees.

To boost planting trees on private land and reduce runoff, Baltimore County last spring—in partnership with nurseries—distributed coupons that gave homeowners $10 off the price of a tree.

“I’ve talked with urban foresters from L.A. to Baton Rouge and Cincinnati,” Banks said. “We all have similar problems, but the difference is in the level of community interest and involvement. Those places with it are the most successful.”

Officials say that watershed groups and other civic organizations will also be needed to convey the importance of urban trees and help get more in the ground.

The Alliance for the Chesapeake Bay, a regional environmental organization, is the liaison for the tree canopy goal in Pennsylvania. The Alliance worked closely with Columbia to develop its goal and find ways to support it, including the establishment of a grow-out station on local farmland. Tree plantings at private residences were free to the landowners, with half of the costs covered by a grant and the other half through the Columbia shade tree commission.

“Communities that are raising their hands and signing on are getting a lot of help,” Claggett said. “They’re receiving technical resources for the assessments and help finding locations with planting potential. We’re even helping them to look at specific tax parcels and the best ways to communicate with their owners.”

State and federal funds have supported the effort. The Chesapeake Bay Trust, a private environmental grantmaker, has given an extra boost to tree canopy projects in Maryland.

The Trust has awarded grants to Annapolis, Baltimore, Cumberland, Hyattsville, and the Herring Run Watershed Association. Along with funding, each recipient receives three training sessions and 16 hours of technical assistance from the Center for Watershed Protection.

Rockville began seeking funds for an assessment, but discovered that much of the needed imagery already exists at the University of Maryland and the Maryland Department of Natural Resources.

“In some cases, you don’t know what resources are out there until you ask the question,” Galvin said.

He hopes that the tree canopy goal will raise awareness about the importance of urban trees and spur more local-level action, whether the community partners with the Bay Program or not.

“Our towns and cities have to remain livable,” Galvin said. “They can’t just be concentrated with emissions and waste products. We need trees to help clean the water, clean the air, and to keep these places environmentally viable.”