Tree-Planting Drive Seeks To Bring a New Urban Cool
Monday, September 4, 2006
SACRAMENTO -- This city believes an answer for global warming is growing on trees.
About 375,000 shade trees have been given away to city residents in the past 16 years, and there are plans to plant at least 4 million more. To receive up to 10 free trees, residents simply call the Sacramento Municipal Utility District, a publicly owned power company.
"A week later, they are here to tell you where the trees should be planted and how to take care of them," said Arlene Willard, a retired welfare case worker who with her husband, John, has planted four SMUD trees in the back yard of their east Sacramento house.
Perhaps the most arresting feature of Sacramento's shade crusade is its rarity, despite federal research showing that carefully planted trees can lower summertime temperatures in cities, significantly reduce air-conditioning bills and trap greenhouse gases responsible for global warming.
Most American cities have shrinking tree canopies in relation to their growth. That's because of inadequate budgets to maintain older trees and a failure to plant shade trees in new residential and commercial developments, according to federal experts, tree-planting organizations and scholars of urban ecology.
A number of major cities have launched sizable tree-planting programs -- including Washington, Baltimore, Minneapolis, Chicago, Denver and Los Angeles. Still, the decline in tree cover has been accelerating since the 1970s, especially on private property and new development, according to American Forests, an environmental group in Washington that uses satellite imagery to document tree cover across the country.
"This is like a creeping cancer," said Deborah Gangloff, the group's executive director. "In the two dozen cities we have studied, we have noticed about a 25 percent decline in tree canopy cover over the past 30 years. This is a dramatic trend that is costing cities billions of dollars."
And the trend continues even as cities heat up. Along with much of California, Sacramento set a record for heat this summer, with 11 straight days above 100 degrees. Federal scientists say that the first six months of this year were the warmest on record in the United States and that the five warmest years over the past century have occurred since 1998. The average nighttime temperature in Los Angeles is seven degrees warmer than it was a century ago.
Many major utility companies are declining to act on the connection between urban trees and energy savings, according to Agriculture Undersecretary Mark Rey, who oversees the Forest Service.
"It is one of our new focuses to give them information and incentives to do this," Rey said, adding that the Bush administration is planning a meeting with utilities to convince them of the financial logic of urban trees.
Three shade trees strategically planted around a house can reduce home air-conditioning bills by about 30 percent in hot, dry cities such as Sacramento, and a nationwide shade program similar to the one here could reduce air-conditioning use by at least 10 percent, according to Energy Department research.
Washington is among the cities with the largest reduction in dense tree cover, with a 64 percent decline from 1973 to 1997, according to American Forests. Althouh there has since been considerable effort and expense to plant more trees in Washington, experts disagree about whether the tree canopy has been stabilized. They do agree that rapid canopy decline continues in Washington's outlying suburbs.