Over the past decade, countless visitors on southeastern Vermont’s Mount Ascutney have read the words on two interpretive panels describing ongoing research that began as a graduate student’s research project there. Through the years, the panels have faded and weathered, but now they are new again after U.S. Forest Service researchers installed updated replacements in the summer of 2016.
One panel, “Cleaner Air and Healthier Forests: A Science and Policy Success Story,” explains how acid rain is formed when precipitation mixes with nitrogen and sulfur pollutants from automobile exhaust and coal-fired power plants—and how the issue prompted Congressional action and launched efforts to study the impacts in order to develop appropriate policies. Researchers began working on Mount Ascutney in 1987 to understand the relationship between acid rain and damage to forests, in particular the high-elevation, acid-sensitive red spruce forests of the Northeast.
Johnny Boggs, a biological scientist with the Eastern Forest Environmental Threat Assessment Center, leads the project on Mount Ascutney today, which has been made possible through partnerships involving the Southern and Northern Research Stations; Vermont Department of Forests, Parks and Recreation; University of New Hampshire; and University of Vermont. He explains that, for 22 years, researchers annually fertilized a series of research plots with low and high levels of nitrogen to simulate acid rain. They visited the plots every four years to take measurements and assess forest health.
“Data indicated that plot-level red spruce mortality was widespread in both the low and high nitrogen addition plots. The nitrogen fertilization likely caused imbalances of other nutrients in leaves and soil that are critical to tree health and survival,” says Boggs.
Findings from the study have informed policy decisions, though there was initially resistance, the panel explains. A market-based system—part of the Clean Air Act—ultimately compelled power plants and vehicle manufacturers to limit pollution emissions. But researchers aren’t yet certain how changes in policy and air quality management implemented in the 1990s have contributed to the health of high-elevation red spruce forests.
In 2010, researchers stopped fertilizing the plots, beginning a new phase of the study. They will continue to measure trees and assess forest health for several more years to understand forest recovery following reductions in acid rain. “This work will further our understanding of how improved air quality benefits soil and foliage conditions,” says Boggs.
The graduate student who began the research project? He remains involved in the work. Steve McNulty went on to study forest responses to a variety of environmental stressors as an Eastern Threat Center research ecologist and now serves as the Director of the USDA Southeast Regional Climate Hub.
The second panel, “Climate Change and Forests,” describes observed and anticipated changes for the forests of Mount Ascutney. McNulty says the research project will expand to address interacting stressors. “Future studies here will examine how high-elevation red spruce forests react to elevated nitrogen levels and climate variability to determine if additional reductions in nitrogen emissions are needed to maintain the health and resiliency of high elevation forests,” says McNulty.
For more information, email Johnny Boggs at email@example.com.