Unearthing insights for a Sustainable Future in a
Rural South Carolina Forest
Dan Richter’s Team Investigates Environmental Effects of Wood Energy p.3
by Tim Lucas
“Wood energy re-circulates carbon that’s already in the biosphere, instead of adding new carbon to it.” His research will estimate wood energy’s full-carbon budget, including emissions associated with the harvesting, processing and transportation of wood products.
Burning wood gives off little mercury and sulfur, and emissions of carbon monoxide and other pollutants can be minimized before they are discharged in the plant’s exhaust. Technological advances in wood combustion systems mean that pollutant-laden flue gases are re-directed back into the plant’s burners, “so air pollution is minimized,” he says. “The wood is burned to near completion.”
“The chief challenge remaining, in terms of air pollution, appears to be fine particulates,” Richter says. “Medical researchers are increasingly interested in whether respiratory problems are associated with fine particulates from the combustion of many fuels, including wood.”
That question, along with fears about the overexploitation of forest resources, has led some environmentalists and paper companies to resist wood energy’s entry into the green energy mix in the United States. Rural schools, hospitals, prisons and industrial plants in heavily forested northeastern states like Vermont and Maine have begun burning wood instead of fossil fuels, he says. And a few urban areas, like Akron, Ohio, also are experimenting with it. But for the most part, wood energy remains the red-headed stepchild of U.S. renewable energy.
Richter—who was one of three scientists invited to speak at the National Academy of Sciences this summer in conjunction with the opening of a new Smithsonian Institution exhibit on soil—is working to address these concerns. His search for answers leads back to the clear-cut plots and forested buffer zones of the Calhoun Experimental Forest.
Over the years, his teams’ research at the site has focused on four core issues: carbon cycling, nutrient cycling, soil-ecosystem acidification, and forest recovery. Their findings, along with results from studies at research plots they maintain at Duke Forest, have resulted in more than 50 peer-reviewed papers in Nature and other scientific journals, a textbook, and dozens of posters, presentations and book chapters.
“One of the main questions we’re trying to answer is how much wood can be removed from a forest that is growing on highly disturbed land,” Richter explains. “As forest nutrition is depleted by harvests, how does that compare with the regenerative effects of forest development?”
Researchers from around the world are eagerly anticipating Richter’s team’s findings.
“With fossil fuel supplies becoming more scarce and expensive, and with the need to replace carbon-intensive fuels with fuels that are closer to carbon neutral, wood energy is an option for the future. However, it is essential that the full environmental impacts of wood fuel and other forms of bioenergy be fully assessed,” says Pete Smith, Royal Society Wolfson Professor of Soils and Global Change at the University of Aberdeen in Scotland.
photo captions: Richter at the Calhoun Forest; panorama of the Calhoun Forest; Richter, Jason Jackson, Meg Mobley and Jian Wei Li surveying the Calhoun site.