UNIVERSITY PARK, Pa. -- In the past 20 years for which records are available, Pennsylvania received some of the most acidic rain in North America. As a result, our forests have changed profoundly, says a forest hydrologist in Penn State's College of Agricultural Sciences.
"Acid rain is a problem that is both severe and widespread in Pennsylvania," says William Sharpe, professor of forest hydrology. "Available long-term soils and fisheries data are evidence that the problem is a big concern."
Sharpe believes a recent decline in two economically important trees -- the northern red oak in Laurel Hill and the sugar maple in the Allegheny National Forest and Susquehannock State Forest -- is caused by soil acidification that results from acid rain.
"Pennsylvania's forest soils don't neutralize acid easily, so they're very sensitive to acid rain," Sharpe explains. "Soil acidification is one of the most controversial topics in the acid rain debate, but recent research presents clear evidence that our soils are more acidic now than 35 to 40 years ago.
"Also, pools of important plant nutrients in forest soils, such as calcium and magnesium, are smaller than they were a few decades ago," Sharpe says. "We have shown that acid rain leaches these nutrients from the soils."
Acid rain also may cause aluminum concentrations in soil to increase and damage tree roots. "In parts of Pennsylvania, the ridgetops contain high enough concentrations of aluminum to harm forest growth," Sharpe says. "In severe cases, aluminum is stressing the sugar maple and northern red oak," Sharpe says.
"Aluminum that has leached into streams from forest soils also has destroyed entire fish populations from some of the state's most pristine streams."
To address these concerns, Sharpe invited an international team of scientists to tour sites in Pennsylvania and view the problem first hand. The team's impressions and recommendations, as well as research by other scientists, appear in the 266-page, hard-bound book, "The Effects of Acidic Deposition on Pennsylvania's Forests," the first volume of the Proceedings of the 1998 Pennsylvania Acidic Deposition Conference. The book is available through Penn State's Environmental Resources Research Institute for $10 to cover shipping and handling.
A second volume, "The Effects of Acidic Deposition on Aquatic Ecosystems in Pennsylvania" -- a 68-page, soft-cover book with color cover -- is available for $5.
To purchase either book, contact Joy Drohan by e-mail at jrr131@psu.edu, by phone at 814-863-0037, or by writing the Environmental Resources Research Institute, 125 Land and Water Research Building, University Park, PA 16802.
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EDITORS: For more information, contact Bill Sharpe at 814-863-8564.
Contacts: Kim Dionis KDionis@psu.edu 814-863-2703 814-865-1068 fax