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Research at Appalachian will help The Nature Conservancy manage and protect the Bluff Mountain Nature Preserve ecosystem

SaskiaVandeGevel_t.jpgBOONE—The American chestnut tree disappeared from southern forests by the mid-1950s as the result of a an airborne bark fungus growing on chestnut trees imported to New England from Asia. Ironically, the blight that destroyed the species helped clear the way for other trees to thrive.

Dr. Saskia van de Gevel is studying the forest stand dynamics on Bluff Mountain in Ashe County to determine how tree species’ composition and age structure have changed as a result of the chestnut blight. Van de Gevel teaches in Appalachian State University’s Department of Geography and Planning.

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Dr. Saskia van de Gevel, right, is studying forest stand dynamics in Ashe County’s Bluff Mountain Nature Preserve by examining tree-ring samples from chestnut tree logs on the property. Her research is supported by a grant from The Nature Conservancy. Van de Gevel teaches in Appalachian State University’s Department of Geography and Planning. Graduate student Philip White, left, is assisting her with the research. (Appalachian photo by University Photographer Marie Freeman)

Her work is supported by a grant from The Nature Conservancy, which owns and manages the Bluff  Mountain Nature Preserve. Van de Gevel also has received the Wachovia Environmental Research Award from Appalachian’s Graduate School and Office of Research and Sponsored Programs for her research on Bluff Mountain.

With its stands of Carolina hemlock, oak and hickory trees, wetlands and various plants, Bluff Mountain is one of the most ecologically significant natural heritage sites in the southeastern United States. Bluff Mountain was once heavily forested with American chestnut trees. When the chestnut trees died from blight, the forest canopy opened to allow sunlight and rain to reach other tree species.

“The fact we have a site where a lot of chestnut tree logs have remained intact over the last 70 years provides an incredible opportunity to look at forest change,” van de Gevel said. Working with graduate and undergraduate student assistants from Appalachian and colleagues from the Department of Geography at the University of Tennessee, van de Gevel has collected cross-sections from 20 chestnut tree logs at Bluff Mountain.

“The Nature Conservancy wanted someone to collect tree-ring samples from the chestnut logs before a prescribed burn on the property occurred,” van de Gevel said. “They didn’t want forest history and climate information contained in the logs to be lost.”

“This is important work for The Nature Conservancy,” said Megan Sutton, Mountains Stewardship Program Manager for the conservancy. “This research will help us manage this important ecosystem in the future. A more complete understanding of how the blight changed the forest will help us make better decisions about the future of the preserve and about forest restoration work that we are currently undertaking. This is especially important as we make management decisions around the issue of climate change, which is likely to bring significant changes to this and other Appalachian ecosystems.”

Van de Gevel will use a science known as dendrochronology, a method of matching growth patterns in annual rings from trees or logs, to analyze  cross-sections taken from the chestnut logs. She and her colleagues are also using thin core samples collected from living trees on Bluff Mountain and cores carefully extracted from the early 19th century structures at Rocky Mount Historic Site near Johnson City, Tenn. Core samples collected from live red and white oaks on the Bluff Mountain property indicate some of the trees are more than 250 years old.

While the outmost portions of many chestnut logs have decayed, some cross-sections reveal outermost rings that formed during the 1890s, van de Gevel said.  Many of the chestnut logs started growing as chestnut trees on Bluff Mountain in the mid-1600s.

By integrating the data from the logs and live trees at Bluff Mountain with the area’s land-use history, patterns of forest dynamics and potential relationships between local tree growth and climate, van de Gevel and her colleagues can better understand the ecological processes and human-caused changes occurring at the site and extend their knowledge to land managers and the general public.

“Tree rings are an important tool for understanding forest dynamics and climatic variability on multi-century scales,” van de Gevel said. “The annual nature of tree growth permits the tree to serve as a bio-recorder for the duration of its lifetime.  By studying these annual growth rings, we can determine how forests have changed over time and relate growth with climatic factors such as temperature, precipitation and drought.  As no prior dendroecological investigations have been conducted on Bluff Mountain, this research will fill an important gap in our understanding of the historical ecology of Bluff Mountain forest communities.”