Prescribed fire management impacts on forest succession trajectories in future southern Appalachian forests

Abstract

Prescribed fire use has increased throughout the Southeastern U.S. and Southern Appalachian Mountains as an effective tool for landscape-scale fuels reduction and ecosystem restoration, yet may become more difficult in extreme weather conditions. The objective of this study is to assess long-term (100 year) forest response to divergent scenarios of climate and prescribed burning initiatives. We modeled 48, 6.25 ha sites distributed throughout western North Carolina that were selected by combining historical geospatial prescribed fire data and input from regional fire managers. For eight functional groups of tree species, we simulated 21 scenarios combining seven different prescribed fire intervals and three climate scenarios. We found that climate, burn interval, and initial forest community composition affect total biomass and functional group composition, with the least biomass occurring under hotter drier conditions and the greatest number of fires. Changes in functional group composition were most influenced by the initial forest community, then number of fires, then climate. Forest demographics were also sensitive to prescribed fire; young cohorts (<30 years) increased only when sites were burned every 10 years or more frequently, while intermediate age cohorts (30–60 years) increased only when burned every 5 years, regardless of climate and initial forest community. Our simulations and scenario design help to discern the effect of varying climatic and weather conditions, fire management, and existing forest composition on future forests. This work can be used to support fire and natural resource management planning by exploring a range of uncertainty associated with different fire and climate conditions.