PLANT MORE TREES

Every schoolchild knows there is no poem so lovely as a tree. But does everyone know just how green they can be? According to Deborah Gangloff, the executive director of American Forests, a nonprofit conservation group, “Three trees will sequester one ton of CO2 over a lifetime of 55 years.” She notes that a carbon calculator on her group’s Web site tells you how many trees you can have American Forests plant (for a $1 donation each) to make up for the miles you drive or the fuel you use to heat your home. “This is a feel-good thing,” Gangloff admits, “but we are really planting those trees.” American Forests programs have planted 25 million trees since 1990. Some trees do more good than others. When it comes to helping the environment, urban trees “can be 15 times more effective than a tree merely standing in the forest,” Gangloff says. Dan Burden, who founded Walkable Communities in 1996 in part to promote planting and maintaining trees in urban settings, claims in his booklet, “Urban Street Trees,” that “a single street tree returns over $90,000 of direct benefits (not including aesthetic, social and natural) in the lifetime of the tree.” Shade trees near residential and commercial buildings can reduce demand for air-conditioning; deciduous trees lose their leaves in winter, allowing the sun’s heat through. Researchers have developed models to guide property owners on how to preserve and plant trees strategically to realize the greatest energy savings. The Lawrence Berkeley National Laboratory in California, for example, determined the impact of planting shade trees and found that costs of cooling dropped 8 to 18 percent and the costs of heating declined 2 to 8 percent when a residential building was provided with a tree canopy roughly equal to two strategically placed trees.