Characterizing effects of prescribed fire on forest canopy cover in the George Washington and Jefferson National Forests

Abstract

On the George Washington and Jefferson National Forests, managers have used prescribed fire to create and maintain early-successional and open forest conditions across large areas. We used a landscape-scale and image-based approach to assess the extent that prescribed fires, including repeated fires, have created these forest conditions and put the results in context of the new George Washington National Forest management plan. At the landscape level, early-successional forest made up an average of 5 percent of burn unit area after one burn, 9 percent after two fires, 17 percent after three fires, and 14 percent after four fires. On average across all burn unit acreage, open forest made up 5 percent of the area after one burn, 7 percent after two burns, 9 percent after three, and 8 percent after four fires. The forest plan desired condition of 12 percent of the area in early-successional forest was met after three or four fires and was exceeded in some individual burn units. It is harder to achieve open-forest than early-successional conditions using prescribed fire alone. We also examined possible drivers of canopy gap creation in these forests. Vegetation type and heat load index, a topographic-based measure of solar radiation received by a site, were important predictors of where canopy gaps formed after prescribed fire.