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Beneficial urban trees are in decline

By John Balzar
Los Angeles Times

	KAREN TAPIA-ANDERSEN / LOS ANGELES TIMES "We're eliminating trees," says Eric Oldar, a pioneer in California's urban forestry program. "We're letting them become trivialized."
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Actually, crape myrtles aren't trees. They are shrubs that grow to look something like trees in miniature.

And that, in short, is the problem. Our grand city trees are disappearing.

The towering trees that provide us cooling shade and save on air conditioning; the trees that give roost to birds; the broad-shouldered trees that soak up the heavy rains before they gather into floodwaters; the trees that cleanse our air and muffle the roar of metropolitan life; the trees that soften the sharp corners of crowded living and connect us to the majesty of nature — the trees are going away.

In their place: pygmy stands of crape myrtles, or clumps of even smaller bushes. Or just beds of redwood chips scattered atop plastic sheeting to make sure that even weeds don't grow.

"We're eliminating trees," says Oldar with a deep sigh. "We're letting them become trivialized; without really paying attention, we're letting them disappear."

Oldar is a forester and a pioneer in California's tiny urban forestry program, which is tucked away with firefighters in the state Department of Forestry. He has devoted most of his 27-year career to promoting urban forests.

In our mind's eye, if not in reality, cities of the United States are made glorious by their trees, and always have been. In truth, though, our cities are turning from green into gray — at an alarming rate and with surprisingly costly consequences:

• According to American Forests, the nation's oldest citizen conservation organization and self-proclaimed "voice of the trees," the nation's urban areas as defined by the Census Bureau have lost 21 percent of their tree cover in the past decade. Viewed over longer time spans, the news is even worse. For instance, Washington, D.C., a city renowned for its blossoming cherry trees, has sacrificed 60 percent of its heavy tree canopy in the last generation.

• Even before the recent wildfires, San Diego and surrounding communities had lost 27 percent of their green canopy in less than 20 years. In an extensive study using satellite imagery, scientists at American Forests calculated that the trend, if unchecked, could cost taxpayers millions to manage storm-water runoff. Added pollution that trees would otherwise absorb could make it more difficult for the region to attain clean-air standards.

• A joint study by state and federal forestry agencies determined that California cities have about 177 million trees and 242 million empty planting sites. The potential savings are huge. Three good trees planted around your house can reduce air-conditioning costs 20 percent or more.

• In a project sponsored by the National Aeronautics and Space Administration, meteorologists determined that clearing trees had made temperatures in Atlanta 5 to 8 degrees hotter than in outlying areas. This has created an urban "heat island" that generates increasingly violent thunderstorms over the city and its suburbs, contributing to flooding.

• And the topper: Incalculable millions are spent to process valuable tons of trees as common garbage. According to studies by the U.S. Forest Service and the International Society of Arboriculture, more potentially usable wood fiber is produced in urban areas each year than is harvested from U.S. national forests — much of it sent into an already overburdened waste stream.

The numbers grow mind-numbing. Potential energy savings run into the billions of dollars if we would only shade ourselves under more trees — $3.6 billion annually in California alone, according to a study by the U.S. Department of Agriculture. The savings from needless flood control is even greater. And global warming? Trees sequester vast amounts of carbon, which has been blamed for making our atmosphere a heat-trapping greenhouse.

Some municipalities are stepping in. San Diego has undertaken a 20-year replanting program. In the past few years, the city of Los Angeles has begun planting more curbside trees than it cuts down, and just last month announced that a $1 million federal-state transportation grant would be used to plant 3,500 more trees — utilizing crape myrtles only when planting space demands it.

Elsewhere, though, trees tend to occupy far lower rungs of the municipal priority list, notwithstanding common sense or the law.

In Oldar's idealized vision of California's future, the challenge is not quite as simple as planting trees. But almost. It must be the right tree in the proper place — no single-species urban forest monocultures that are prone to attacks like Dutch elm disease or the insect assault that has killed 30,000 eucalyptus trees in Los Angeles in the past 19 months. Plantings need to be spaced out so that entire neighborhoods of trees don't reach maturity and begin to die off at once, as is happening now in post-World War II subdivisions.

Still, California remains headed down what Oldar calls "an insidious slope": Great shade trees are vanishing, leaving pygmy urban forests and gray-scapes.

Why?

Municipal governments manage trees but have no incentive or requirement to promote energy conservation, storm-water management or pollution abatement, Oldar complains. That's the chore of other agencies.

On the other hand, local governments are required by law to reduce the volume of waste they send to landfills. They are charged with repairing sidewalks and curbs damaged by tree roots. As a consequence, trees have become a costly nuisance, not an asset to local officials. Who can blame them for the current trend to plant smaller shrubs, like the crape myrtle?

As for the potential value of wasted lumber, cities consider this merely theoretical, if they consider it at all. The hidebound lumber distribution system in the United States is dominated by giant chain operations that have little interest in sundry lots of variety woods produced in urban forests.

Meanwhile, developers, trying to maximize densities, also are planting bushes instead of trees. Ditto homeowners with a mind to expand their houses to the property lines. Thus, the crape myrtle is now the most popular tree in urban California.

Standing outside his office, Oldar surveys the skinny row of 12-foot-tall myrtles. "See any signs of birds there? Any nests?" He pivots 180 degrees and looks heavenward to the top of a shapely sycamore, where a large nest is silhouetted against the sky. In the summer, these trees would tell another important story — that the crape myrtles generate hardly enough shade to cover the bonnet of a compact car, while one lone sycamore shelters the forestry department offices all afternoon.

Added up block by block, the consequences can be startling. In the various studies of tree cover in Atlanta, scientists measured the downtown air temperature at 86 degrees while comparative surface temperatures were 85 to 90 degrees in the shade of trees and 127 to 129 degrees in direct sun. In one seven-house development built by Atlanta's Habitat for Humanity, scientists determined that homeowners would save $951 in energy and $268 in storm drainage charges each year if adequate trees were planted and allowed to mature.

These days, even homeowners cannot be counted on to keep their neighborhoods green. In Los Angeles, the city government owns 1.5 million to 2 million trees, while businesses and homeowners are responsible for 10 million.

And while many citizens are happy to tell pollsters all the virtues of tree-lined streets, in practice a good many favor trees everywhere but on their own property, worried about storm damage or tree roots clogging their pipes or squirrels tangling with their house cats or the mess of leaves in autumn. More and more, they turn over yardwork to gardeners who are untrained in tree care.

In arid climates such as Southern California, the fresh water necessary for all types of vegetation is increasingly part of the civic conversation, or should be. In this, trees generally fare well — with many varieties requiring only about one-third the water of a lawn, and then, in turn, providing shade that conserves soil moisture for other plants.

It would take only reasonable effort to increase the shade-tree canopy to 25 percent or 30 percent of our residential landscape, Oldar maintains.

"That's realistic, and that's what I'd like to see," he says. "What I fear is the mind-set of doing nothing, that people won't appreciate trees generally."

In that case, trees may wind up like covered bridges, a quaint part of America's past. Within a generation, perhaps only 6 percent of our cities will be shaded by trees — with the corresponding reduction in the quality of our lives.

"That," Oldar says quietly, "is what I fear for my kids. They'll wake up in the future and wonder: Where did it all go?"

Copyright © 2004 The Seattle Times Company