Allegheny National Forest health

Since 1985 72 percent of the forest land on the Allegheny National Forest has been subject to at least one moderate to severe defoliation from any of three native or three exotic agents. In addition, droughts affected the forest in 1972, 1988 and 1991. As a result, at least 20 percent of the forest shows tree mortality in from 10 to 80 percent of the overstory trees. Sugar maple is the most seriously affected species. The impacts of this mortality are compounded by the impacts of up to 70 years of overbrowsing by white-tailed deer. Long-term silvicultural research studies were reexamined and showed that most of the sugar maple mortality is occurring in sapling and pole-size stems, mortality is worse on dry than on wet sites, and even-age silvicultural treatments, especially thinning, are associated with reduced amounts of mortality and reduced rates of mortality.