WILDFIRE DAMAGE ASSESSMENT OF A YOUNG OAK FOREST IN PENNSYLVANIA

A large area of mature mixed-oak (Quercus spp.) forest was clearcut in the early 1990s on a dry mountain plateau in south-central Pennsylvania. The majority of the developing forest was burned from an intense wildfire in 2005. Our 2009 vegetation survey revealed that the unburned areas contained a high density (3579 stems per acre) of sapling and pole-sized trees dominated by mixed-oaks, red maple (Acer rubrum), sweet birch (Betula lenta), and black cherry (Prunus serotina). The burned areas had 43% lower tree density, including fewer oaks and black cherry, but a higher proportion of lower value trees (e.g., black locust; Robinia pseudoacacia). In the burned areas, 91% of surviving oaks had basal fire scars averaging 39” in length, were overwhelmingly multiple-stemmed after being top-killed by fire, and shorter in height and smaller in diameter than the oaks in the unburned units. The burned units had higher cover of shrub and herbaceous species. The results of this study suggest that intense wildfire can significantly damage young oak forests, and that the negative direct and indirect effects of this will persist long into the future.