Acid Rain, Other Stressors, Wreaking Havoc In Mtns

Travel to the upper elevations of the Appalachian Mountains, and you’ll find forests that have suffered serious damage. Fraser firs and spruce stand like skeletons against the skyline. Northern hardwoods — beech, maple, birch — look as if winter has descended, even in the spring.

What has caused this widespread devastation? Some blame insects like the balsam woolly adelgid or the budworm or the Southern pine beetle. Others point to acid rain as the underlying culprit. Most scientists agree that a combination of forces is at work.

Dr. Harvard Ayers, chairman of Appalachian Voices and a professor of anthropology and sustainable development at Appalachian State University, has directed pioneering research on the decline of the hardwoods from the Allegheny National Forest in Pennsylvania through the Great Smoky Mountains of North Carolina and Tennessee.

Ayers flew over the mountains of Pennsylvania and eastern West Virginia last summer. “I saw thousands of acres of declining trees,” he says. “We can’t unequivocally state that they’re killed by air pollution because there are other causes, too, like drought and bugs and disease.

“But one thing is certain: Every tree species in the higher elevations and even some in the lower elevations are in trouble over much of their range. That includes about a dozen hardwood species plus conifers like spruce, fir and hemlock.”

While some species began to decline as early as the 1950s, the Southern Appalachians saw a dramatic change in the mid-1980s when a drought hit the region. The presence of the balsam woolly adelgid also caused problems for the Fraser fir.

The overarching problem, however, appears to be acid rain and ozone. Marty Bergoffen, campaign coordinator for the Southern Appalachian Biodiversity Project, calls the situation “horrible.”

“If you go up to Mount Mitchell, you see how bad the problem is,” he says. “Pretty much the entire spruce-fir forest on top of Mount Mitchell is dead at this point.”

Bergoffen notes that research by Dr. Robert Bruck of N.C. State University proves that acid rain and cloud deposition are the primary culprits in the loss of spruce and fir forests.

In 1984, Bruck selected 272 healthy red spruce and 213 healthy Fraser fir in 16 plots, Bergoffen says. By 1986, 9 percent of spruce and 16 percent of fir had died. By 1987, 41 percent of spruce and 49 percent of fir had died. Following a highly acid cloud event in June 1987, the spring flush of new needles showed significant necrosis.

Large amounts of ozone and acid rain surround trees in the form of clouds or fog or hoarfrost. Basically cloud formations have a pH in the range of 2.5-3.5, which is incredibly acidic, Ayers says.

Normal rainfall is slightly acidic at 5.6 on the pH scale. When you drop to 2.6, you’ve gone down three pH points or 1000 times the acid because it’s a logarithmic scale, Ayers says. Cloud water is 100 times more acidic than unpolluted rainwater.

Ozone and acid rain are worse in the higher elevations because more precipitation occurs there, and cloud water is more prevalent. Places like the Smokies can get 80-100 inches of rainfall a year, Ayers says. Mount Mitchell, the highest peak west of the Mississippi River, is surrounded by cloud water 60-80 days a year.

The fact that ozone levels don’t drop at night in the mountains adds to the problem. In the higher elevations, the ozone levels are constant, says Michael Shore, Southeast air quality manager for Environmental Defense. The trees are simply bathed in ozone for 24 hours a day.

Equivalent of AIDS


While acid rain and ozone don’t kill trees outright, they so compromise the tree’s root system that the trees are vulnerable to other stressors. The balsam woolly adelgid was around for 50 years before it became a problem for Fraser firs, Ayers says.

“The insect was present in the Mount Mitchell area in the 1930s, but we didn’t start seeing any significant death until the ‘80s,” he says. “That period also happened to coincide with the occurrence of higher levels of pollution.

“Spruce trees had a similar experience. This species managed to survive the budworm and droughts until the 1980s. But after pollution became an issue, they no longer were able to withstand the pests and drought.”

One of the things that acid does is reduce the root system, Ayers says. When you reduce the root system, especially the capillary roots, the tree is not prepared to deal with a drought. Acid rain and ozone are to trees what AIDS is to humans, Ayers says.

“Those trees have the equivalent of AIDS, which is basically brought on by air pollution. With a weakened system, any normal stressor — and certainly something as vile as the balsam woolly adelgid — can finish them off.”

Scientists and concerned citizens alike are working to pass laws that would reduce the levels of acid rain and ozone. Environmental laws governing auto exhaust have already greatly reduced pollution caused by automobiles. The new models are probably producing 10 percent of the pollution that a 60s model did, Ayers says. Another 10 percent reduction is scheduled for this decade.

But the old smokestack industries are still a problem. “In the 1970s, people thought those old coal burners would phase out over time,” Ayers says, “but because they are so cheap to run, they are continuing to spew more and more pollution — even more than in the 70s.”

A coalition of environmental, public health and citizen groups recently developed the North Carolina Clean Smokestacks Plan to document the health and environmental problems that coal-fired power plants and other sources generate. The plan sets forth a policy framework to clean up North Carolina’s air.

The document notes that power plants emit 82 percent of all sulfur dioxide air emissions, 45 percent of nitrogen oxides and 65 percent of mercury. Automobiles and other mobile sources emit 48 percent of the nitrogen oxides.

The plan calls for the N.C. General Assembly to pass a comprehensive bill requiring the state’s power plants to meet aggressive clean emission standards for sulfur dioxides and nitrogen oxides, as well as lower mercury emissions. “Controlling air emissions from power plants is the single most important action that North Carolina can take to clean its dirty air and thereby ensure the health of its citizens, environment and economy for future generations,” the document says.

The bill passed in the N.C. Senate by a vote of 43 to five, but has been stymied in the House of Representatives.

Proponents of the bill acknowledge that its passage would involve some cost. “The bottom line is it’s not cheap to improve our air quality,” Shore says, “but it’s even more expensive to leave our air quality as it is.” He says if the bill passes, it would add $2 per household per month to the electric bill.

“What needs to be done is all of us need to somehow get acid rain and the forestry issues on the front burner of policy makers,” Shore says, “so they can appreciate the problem and act on it.”

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