A University of Vermont researcher says red spruce forests in the Northeast that were once damaged by acid rain are recovering, thanks to stronger pollution controls.
In the early days of acid rain research, red spruce trees on Camel’s Hump in Vermont were seen as the canaries in the coal mine. The conifers were dying from acid rain, caused by pollutants released mainly by Midwest fossil fuel power plants.
The late UVM scientist Hubert “Hub” Vogelmann documented the trees’ decline on Camel’s Hump. His research provided compelling evidence of the environmental impact of acid rain.
But 1990 amendments to the federal Clean Air Act limited nitrous oxide and sulfur dioxide emissions.
And now the trees are recovering.
Alexandra Kosiba, research project coordinator at UVM’s Forest Ecosystem Monitoring Cooperative and the Rubenstein School of Environment and Natural Resources, studied red spruce in 52 plots spanning five states.
Her paper, published with co-authors Paul Schaberg of the USDA Forest Service and UVM researchers Shelly Rayback and Gary Hawley, says that more than 75 percent of red spruce trees and 90 percent of the plots showed increasing growth since 2001.
“The Clean Air Act and the amendments that happened [in 1990] really did help," Kosiba said. "We see this ecosystem recovery, but it also took quite a long time."
And while Kosiba's findings reveal good news, there's also some bad news: Kosiba said one reason the trees are showing increased growth is due to a longer growing season related to climate change.
It’s also likely that the forest will suffer in the long run as the climate warms.