The Clean Air Act Amendments of 1990 were supposed to solve the acid rain problem of the 70’s and 80’s, but a new study by scientists at the Hubbard Brook Experimental Forest in New Hampshire finds that the Act hasn’t gone far enough.
The Hubbard Brook study, overseen by the U.S. Forest Service, found that despite some decreases in acid rain-causing chemicals such as sulfur dioxide, acid rain continues to remove plant food from the soil that is necessary for tree health.
Both red spruce and the economically valuable sugar maple have died in large numbers as a result. The Hubbard Brook study also found that acid and toxic aluminum in streams and lakes continue to kill fish and other life.
For about two decades, scientists in the central and southern Appalachians have been observing tree death in the higher mountains, from North Carolina to Pennsylvania. The Great Smoky Mountains National Park, Shenandoah National Park, and the Allegheny National Forest have been particularly hard hit.
Some industry-sponsored scientists blame the decline of forests in these areas on insects and disease, including the balsam woolly adelgid for fir, the spruce bud worm for the red spruce, the gypsy moth for the oaks, and the maple thrips for the sugar maple.
There’s even the theory by some Pennsylvania scientists that deer are killing the maples in the Allegheny National Forest by browsing their leaves, despite the fact that the dying maples are 10-20 times the height of the marauding deer.
Other scientists reach a different conclusion. They have noticed that many, if not most, of the tree species in the eastern mountains are declining and dying at alarming rates all at once. They point out that while bugs and diseases are involved in some cases, the only common factor for all these dying species is a high level of air pollution from the burning of coal and other fossil fuels.
According to North Carolina State University scientist Dr. Robert Bruck, every species of tree, just as with humans, has numerous diseases and pests that can cause health problems. But like humans, if the trees are healthy, they can fight off the normal challenges thrown at them by Mother Nature.
Bruck and other scientists like Dr. Orie Loucks of Ohio’s Miami University feel that air pollution is weakening the trees, giving them the equivalent of human AIDS. As the common cold can kill such a human, so a gypsy moth can easily take out a weak oak.
The Hubbard Brook study gives further credence to the theories of Bruck, Loucks and a growing body of scientists who are willing to point a finger at human pollution rather than the bugs so beloved by polluting industry and its scientists.
Hubbard Brook researchers found, for instance, that acid deposition takes the vital nutrient calcium directly from the needles of the red spruce, making the trees susceptible to freezing, and leading to over a 50% loss of large red spruce in areas of the Northeast.
In Pennsylvania, extensive mortality in the sugar maples in and around the Allegheny National Forest is now seen not as overbrowsing by deer, but as a lack of soil nutrients such as calcium and magnesium. Again, acid deposition is implicated, as Pennsylvania has some of the highest levels of acid rain in the country.
Research indicates that acid deposition is higher in many areas of the southern Appalachians than it is in the Allegheny National Forest. On Mount Rogers, Virginia’s highest peak, soils have acid levels 5,000 times that of unpolluted rain water.
Despite extensive research on the Northeastern forests resulting in studies like the recent Hubbard Brook report, Forest Service officials in Virginia say that while there seemed to be a problem with the forest they are supposed to protect, funds were not available to do such studies. The same is true in North Carolina and Tennessee forests.