Hotline, Spring 2001
At the GASP Annual Meeting on December 5, 2000, GASPers mingled with old friends and new, enjoying cider and cookies surrounded by a bevy of bright holiday poinsettias. As a bonus, GASP members found many new faces in the gathering. Landscape architects, students, hikers and regional planners were drawn to the evening’s presentation by their concern that there is indeed an Appalachian Tragedy and that eastern mountain forests in general are under duress from air pollution. The Appalachian range stretches from Alabama to Maine through Pennsylvania and holds some of our most precious parks, such as the Great Smokey Mountains National Park in Tennessee and North Carolina, and the Shenandoah National Park in Virginia.
Our speaker for the evening, Harvard Ayers, Ph.D. of Appalachian State University, Chair of the non-profit group Appalachian Voices and co-editor of An Appalachian Tragedy, showed a beautiful multi-media slide show and spoke to us about the degradation and decline occurring in this vast range of invaluable forest. For example, the Great Smokey Mountains National Park, in a nine year study (‘91-’99), recorded in 1998 the largest single-year cumulative ozone exposure of any National Park in the U.S. The park had over twice the number of ozone hours over 60 parts per billion (ppb) of even Atlanta, GA, the most ozone polluted city in the eastern U.S. While peak concentrations in Atlanta were higher and drop to near zero at night, in the mountains the levels remain high both day and night often for days at a time.
Many plant species are susceptible to ozone damage. Some of the more susceptible trees are Black Cherry and Red Oak. Research has shown that current ozone levels result in more than a 10% reduction in wood growth in Northeast forests and contribute to as much as $345 million in agricultural losses from soybeans alone in Illinois, Indiana and Ohio.1
Another primary stress in the forest is acid rain, as well as dry deposition of acid in the form of sulfate. In the higher locations over much of the East, precipitation can be 10 to 100 times more acidic than pure rainfall. The most acidic pH tends to be found in cloud water, which hangs on the mountaintops for many days of the year.
A Pennsylvania State University research institute newsletter2 recently reported that “the mean annual precipitation-weighted pH average at the fourteen-site Pennsylvania Atmospheric Deposition Monitoring Network was 4.26 statewide in 1998 with the lowest growing season pH (4.02) occurring at Crooked Creek in western PA.” This is less acidity than was seen in the 1980s and early 1990s but “at 13 sites, an increase in sulfate concentrations was evident in comparison to the previous three years. This reflects the gradual increase in sulfur dioxide emissions in the eastern U.S. since 1995. Wet deposition of sulfate and nitrate was highest in western Pennsylvania.”
To bring the problem closer to home, An Appalachian Tragedy reports, “The Allegheny National Forest has been afflicted by what its supervisor has called a ‘full forest decline,’ with sugar maple death the most dramatic manifestation. Here in some stands, maple mortality has reached 80% with the rate of regeneration down to zero.” Bill Sharpe, a forest hydrologist at Pennsylvania State University says, “for the past 20 years, Pennsylvania has received some of the most acidic rain in North America.”
In a process called soil acidification, acid rain releases plant nutrients magnesium and calcium from the soil but also releases the potentially toxic element, aluminum. Aluminum can damage root tips, limiting uptake of nutrients at the same time the acidity is diminishing the calcium and magnesium necessary for tree health.
Sharpe planted sugar maple seedlings in soils at declining sites. He fenced out the deer and weeded out the pervasive acid-loving Hay-Scented Ferns, but the seedlings still didn’t grow. He learned that sugar maple seedlings won’t grow in soils containing less than a certain ratio of calcium to aluminum. In selected plots where dolomite limestone was added (lowering the acidity and adding calcium), there was a dramatic increase in the health of the sugar maples even in the face of major droughts and insect infestation.
Perhaps the U.S. thought it had set itself on a path to solve the acid rain problem when Congress in 1990 passed measures in the Clean Air Act Amendments to cut sulfur dioxide emissions, targeting 110 utilities mostly in the Ohio River Valley. Implementation began in 1995. Nevertheless, recent observations show that though the acid rain has dropped 15% to 25%, in many places there has been such a build up of sulfate in the soil that it may take some time to wash away. Additionally, we have come to recognize the influence of nitrogen oxides in the acid rain problem. The nitrogen oxides turn to nitric acid and add to the acidification problem, not to mention nitrogen oxides’ considerable role in the formation of ground-level ozone.
Major sources of sulfur oxides (60%) and nitrogen oxides (23%) — not to mention mercury — are older coal-fired power plants. Pennsylvania ranks third in the amount of coal fired power plant emissions and Ohio is number one. With recent support by the Supreme Court in a decision that seems to endorse the more stringent, new health-based federal standards for particulates and ozone, we may be getting closer to alleviating the acidic and ozone burden on our forests. There has been a lot of damage; only time will tell if our proposed and active remedies will offer enough help. We must remain vigilant to any efforts to turn around these new standards and other helpful legislation. A spokesperson for the U.S. Chamber of Commerce has already put forth the idea that the Chamber may seek relief from the new standards by looking to Congress for what they did not get from the Supreme Court. The original appeal to the Supreme Court was led by the American Trucking Association and the U.S. Chamber of Commerce.
The other personal steps we can all take to reduce ozone and acid rain are to be energy-efficient and subscribe to cleaner energy generation such as solar, wind, hydroelectric and natural gas whenever possible. Transportation emissions also contribute to ground level ozone formation. Supporting healthier vehicles with fewer emissions and better mileage as well as increasing the availability and use of public transportation will all be part of the solution.
1. “Clear The Air, The National Campaign Against Dirty Power,” Nitrogen Oxides and the Environment Fact Sheet and Report, pg. 2
2. “Penn State Environmental Resources Research Institute Newsletter,” fall 1999, Vol. 29, No. 4
by Suzanne Seppi, GASP Executive Director