Air Pollution and Forests: An Update

Article excerpt

n the tranquil Vermont hills a few miles south of the Canadian border lies Dave Marvin's 800acre farm, where life has been getting tense. Marvin worries about the growing number of dying sugar maples he has seen in the last five years. He knows that U.S. Forest Service studies have been unable to link New England hardwood problems with acid rain or other air pollution.

"I'm not saying I can take you to a tree and tell you acid rain killed it," Marvin says, but he is sure he can't accept the Forest Service's no-link conclusions. "If the Forest Service and other scientists are wrong," he says, "I've lost everything. If I'm wrong, we've lost very little."

Marvin's feeling about his maples is very much like the feeling citizens all over America have about what seems to be an increasing number of dead trees and dying forests. And like Marvin, the public feels government has been too slow to act.

Both President Bush and William Reilly, the conservationist Bush has named head of the Environmental Protection Agency, have put air pollution list. Most scientists and government experts also feel it's important to start cleaning up now. Those who are most deeply immersed in the details of both forestry and budget struggles, however, are afraid headlines like "The Rain That Kills" and "Rain in Northeast Surprisingly Acid"' will lead to throwing money at the problem to appease public opinion while neglecting research and action in areas where results might be sure and important.

The effectiveness of our attack on air pollution may depend on whether the public and politicians have the patience to let the bandwagons roll by until they can absorb complex findings from chemical and biological research.

To learn what air pollution might be doing to forests, the Forest Service has joined forces with the Environmental Protection Agency. Their joint effort, the Forest Response Program (FRP), began in 1985 as part of the multi-agency National Acid Precipitation Assessment Program. FRP's research is done by four regional cooperatives, one national atmospheric research group, and the National Vegetation Survey.

With a budget of $17 to $18 million a year, the FRP is not the Manhattan Project of forestry, but program manager Gerard Hertel is getting the kind of scientific teamwork that won the war. While the effort may not produce any bombshells, after only three years its work has begun to reshape our understanding of how acid rain and air pollution in general affect trees and forests.

The results already surprise many, cheer some, and distress people who like simple answers.

THE NEWEST FINDINGS

EASTERN HARDWOODS: The Eastern Hardwoods Research Cooperative has produced the first study to document ozone concentrations in forested areas of north-central Pennsylvania and to determine the relationship between ozone dose and hardwood seedling growth in this region." Scientists found that ozone followed the sulfur-deposition pattern and exceeded EPA standards of 120 ppb (parts per billion) on some occasions at three different sites.

One of this group's most important findings was a direct correlation between the pattern of air pollution stretching from Minnesota to Ohio and sulfur levels on the forest floor. Scientists say this is the first concrete proof that soil sulfate levels are significantly raised by air pollution. Sulfur precipitation went as high as 31 pounds per acre per year in Ohio to less than 22 pounds per acre in northern Minnesota. The job now is to demonstrate what effects this extra sulfur may have on the health of forests.

Despite widespread reports to the contrary-including Dave Marvin's observations and definite sugar-maple decline in southern Quebec- preliminary surveys have shown no significant decline of sugar maples and other hardwoods in the Lake States or New England. A 1987 survey conducted by the Forest Service and the state of Vermont reported that -less than 0. …