Tree-Planting Drive Seeks To Bring a New Urban Cool

Although Bush administration officials say urban trees are a priority, spending on the federal Urban and Community Forestry Program has declined by about 25 percent in the past four years, from a high of $36 million annually to a proposed $27 million in the coming year.

"People have been fighting for crumbs for so long," said Mark Buscaino, who quit this summer after three years as director of the federal urban trees program. He is now executive director of the Casey Trees Endowment Fund, a private tree-planting group in Washington.

Tree-planting in U.S. cities has been championed as a way to beautify and civilize the hard edges of urban life. (Before air conditioning, it was also a primary strategy for keeping cities cool.) But a growing body of scientific research, most of it federally funded, shows that urban trees are also shrewd investments.

Sacramento's shade crusade easily pays for itself, with summertime energy savings about double what SMUD spends on trees each year. As they mature, trees already planted by the utility are expected to save enough electricity to power about 14,000 homes.

By planting 10 million trees and fabricating lighter-colored roofs and pavement, Los Angeles could reverse an urban "heat island" effect -- caused by concrete, asphalt and heat-retaining buildings -- that has been increasing for a hundred years, according to a simulation study by the Department of Energy's Lawrence Berkeley National Laboratory. It found that Los Angeles could lower its peak summertime temperature by five degrees, cut air-conditioning costs by 18 percent and reduce smog by 12 percent.

"In the West, where the air is dry, shade trees are more effective in reducing the urban heat island effect than any other measure," said Hashem Akbari, leader of the federally funded research group that studies warming cities at the laboratory. In more humid cities in the East, he said, shade trees -- which increase humidity -- lower air-conditioning bills and clean the air but do not lower the outside temperature.

By absorbing greenhouse gases, lowering urban temperatures and reducing demand for air conditioning, trees planted in cities are far more valuable in combating global warming than trees in rural areas, federal research has shown. Akbari said a well-placed shade tree in Los Angeles is worth three to five trees planted in a distant forest.

His message is finding an audience. This month, Los Angeles is starting a campaign to plant a million trees, part of a free-tree program following the Sacramento model. For every dollar it spends on trees, the city expects to realize a $2.80 return from energy savings, pollution reduction, storm-water management and increased property values, said Paula A. Daniels, a commissioner on the Board of Public Works.

Across much of the United States, though, research confirming the monetary value of trees has not triggered a rush to exploit shade.

Many major private utility companies remain skeptical. In the Washington area, in California and in most of the country, they have steered clear of programs to give shade trees to homeowners, saying it is not clear that it would help the companies' bottom lines.

Critics of big utilities say the companies have a deep institutional bias against urban trees, mostly because they spend vast amounts of money and time repairing tree-damaged power lines.

There are cultural reasons why the research findings have failed to sway the nation's utility managers, transportation engineers and municipal planners, according to Kathleen Wolf, a social science researcher at the University of Washington's College of Forest Resources.

"These people have not yet reconciled how a green living thing interacts with gray infrastructure," said Wolf, whose research is funded by the Forest Service. "There has not yet been a mind shift that says trees are technology. In most American cities and states, we are not having that discussion."

But it is not just engineers and road builders who balk. About one-third of Sacramento utility customers tell SMUD that they do not want to mess with more trees in their yards and will not accept free ones.

"Many people just don't like trees because they are dirty," said Buscaino, the former head of the federal urban forest program. "We have a lifestyle where the last thing on people's mind is trimming their trees."

Iowa is the only state with a long-term record of using state law to push private utilities to plant trees for energy conservation -- and to allow them to recover the cost of the program in electricity rates.

Over the past 15 years, the program has been a spectacular success, according to the private utilities there and Trees Forever, a nonprofit group that helps run the program. In addition to the quantifiable benefits -- half a million trees planted, reduced energy costs and savings on storm-water drainage construction -- utilities say the program has been a public relations bonanza.

"It is difficult to put a value on the community relationships we have built with the trees," said Karmen Wilhelm, a spokeswoman for Alliant Energy, a major utility in Iowa. "It has been wonderful for our reputation."