A tree-ring record of historical fire activity in a piedmont longleaf pine (Pinus palustris Mill.) woodland in North Carolina, USA

Background: Longleaf pine (Pinus palustris Mill.) ecosystems were historically widespread in the North American Coastal Plain and in some southeastern piedmont and montane settings. The naval stores industry, deforestation, and other human activities resulted in an extensive loss (c. 97% loss) of the original woodlands and savannas. Longleaf pine ecosystems are maintained by frequent surface fire which promotes successful regeneration and maintains open canopy conditions and a largely herbaceous understory. Fire regimes (including the frequency and seasonality of fire) likely varied across the entire range of longleaf pine and through time; further research is needed to elucidate this variability. Results: We used fire scars in stumps and snags to reconstruct fire history in a piedmont longleaf pine ecosystem in North Carolina. For each tree sampled, we examined multiple cross sections to avoid omission of fire events recorded by smaller fire scars. Our samples revealed evidence of frequent fire (c. 3-4-year fire interval) beginning in the early eighteenth century and extending to the mid-nineteenth century. Fires occurred in the dormant and early earlywood positions of annual rings and were likely human ignited. Conclusions: To our knowledge, this is the first tree-ring-based fire history in longleaf pine of the piedmont. As such, it offers a rare glimpse into historical fire activity in a now scarce but important ecological setting. More research is needed to develop additional fire chronologies in the piedmont region, including for longer periods of time and for larger spatial areas.

Automated summary

Longleaf pine ecosystems, which were historically widespread in certain regions of North America, have suffered extensive loss due to human activities. This study used fire scars in stumps and snags to reconstruct the fire history in a longleaf pine ecosystem in the piedmont region of North Carolina. The results revealed evidence of frequent fires occurring from the early 18th century to the mid-19th century, offering a valuable insight into the historical fire activity in this important ecological setting. Further research is needed to expand the fire chronologies in the piedmont region for longer time periods and larger areas.