Central Appalachian paleofire reconstruction reveals fire-climate-vegetation dynamics across the last glacial-interglacial transition

Understanding fire-climate relationships in eastern North America is difficult due to human impacts on fire in the region. Predicting future wildfire activity in the region is further complicated by the changing climate-vegetation interactions that will accompany anthropogenic climate change. While the end-Pleistocene glacial-interglacial transition provides an informative climate analog to future warming and changing climatic conditions, there are very few paleofire records resolving this period in eastern North America. Here, we present the first paleofire record (charcoal and charcoal morphology) from central Appalachia to span the glacial-interglacial transition. We find that fire history of the last 27,000 years was characterized by three distinct periods: (1) the glacial (27-17.7 cal kyr BP) with low fire activity burning wood and needle fuels, (2) the deglaciation (17.7-11.1 cal kyr BP) with markedly increased fire activity but unchanged fuel types and vegetation compositions, and (3) the interglacial Holocene (11.1 cal kyr BP to present) with low fire activity, twig, deciduous leaf, rootlet, and herbaceous fuels, and vegetation-dependent fire activity. We further compare our paleofire data with variables (burned area fraction, precipitation, temperature) from the TraCE-21K-II transient simulation and discuss the feasibility of data-model comparisons in providing insights into fire-climate dynamics. Last, we explore the implications of our analyses from Twin Pond for the future of fire in the central Appalachia region of eastern North America. The clear link between fire and temperature evident in our analyses suggests that the region may experience increased fire activity in response to future warming. The roles of precipitation and vegetation on future fire, however, are less clear.