Exploring the Early Anthropocene Burning Hypothesis and Climate-Fire Anomalies for the Eastern U.S.

Abstract

This review explores the long-term role of climate versus human activity on vegetation and fire dynamics in the eastern U.S. Early Holocene warming resulted in a conversion of Picea (boreal) to temperate Quercus and Pinus forests when indigenous populations were sparse but charcoal abundances were relatively high, underscoring the importance of climate. Pyrogenic trees also dominated during the middle Holocene Thermal Maximum period, associated with increasing indigenous populations and high charcoal abundance on most sites. During Neoglacial Cooling (3300 to 150 BP) charcoal levels and pyrogenic trees remained high in the central and southern regions apparently due to Native American and early European burning trumping colder climate. In northern regions, oak-pine and charcoal abundance were distributed on intermittent dry and/or Native American sites. High levels of charcoal and pyrogenic species during the early Holocene and Neoglacial Cooling represent important anomalies in the ecological history of the eastern U.S. While the importance of warmer and drier climate is evident throughout, the Early Anthropocene burning hypothesis is plausible for the eastern U.S. where extensive lightning fires are rare, outside of the southeast coastal plain. The cessation of Native American burning and other early European disturbances were transformative to the ecology of the eastern U.S.