Mon, Aug 15, 2022: 5:00 PM-6:30 PM
ESA Exhibit Hall
Background/Question/MethodsAs climate change increases forest fires worldwide, the need to understand long-term natural and human influences on fire is becoming critical. The nature of fire regimes in New England is still debated. While most works focus on climate as the main driver of fire-related ecosystem processes in the region, historical observations and Indigenous place names indicate that Native peoples used fire to create mosaic landscapes with potential effects on local biodiversity and forest composition. The lack of knowledge on human vs. climate fire regimes due to post-contact, colonialist perspectives limits our ability to interpret past records to model future fire regime scenarios. This study uses fossil charcoal records to determine pre-contact fire size, frequency, and intensity, and understand the role of people vs. climate in Maine’s fires. We collected two sediment cores from central Maine: a small-hollow core from one of the oldest known inland Indigenous settlements and one from a nearby lake. Data on charcoal morphotype, size, and frequency in the sediment record were analyzed using CharAnalysis to determine the history of Northeastern fire regimes. This work will help us understand the role of human-ignited fires in shaping local ecosystem processes, community composition, and forest resilience under climate change.
Results/ConclusionsWe collected a 5 m core from Perch Pond (ME) which radiocarbon dates showed completely include the period of inhabitation of the nearby Hirundo settlement (~250-5000 BP). A small hollow core of 58 cm was taken from a bog near the archaeological site, with a basal date of 9870 BP. We reconstructed the fire history from both records by analyzing local ( >250 µm) and regional (125-250 µm) charcoal. Raw concentrations (particles/cm3) were converted to accumulation rates (particles/cm2/year) using our age-depth model. Statistically significant peaks were identified from a background influx of charcoal using CharAnalysis to reconstruct fire histories from both sites for comparison. Our results, which we present along with several unpublished records from the 1980’s, indicate that there was regular low-intensity fire in central and coastal Maine at least 500 years prior to European settlement. Our synthesis finds that fire use was highly localized and varied over as little as 10 km, indicating human ignition, as lightning-ignited fires are typically high-intensity and burn the forest canopy rather than understory. Our work demonstrates the utility of targeted, small-scale approaches in identifying the fingerprint of cultural fire use.
Results/ConclusionsWe collected a 5 m core from Perch Pond (ME) which radiocarbon dates showed completely include the period of inhabitation of the nearby Hirundo settlement (~250-5000 BP). A small hollow core of 58 cm was taken from a bog near the archaeological site, with a basal date of 9870 BP. We reconstructed the fire history from both records by analyzing local ( >250 µm) and regional (125-250 µm) charcoal. Raw concentrations (particles/cm3) were converted to accumulation rates (particles/cm2/year) using our age-depth model. Statistically significant peaks were identified from a background influx of charcoal using CharAnalysis to reconstruct fire histories from both sites for comparison. Our results, which we present along with several unpublished records from the 1980’s, indicate that there was regular low-intensity fire in central and coastal Maine at least 500 years prior to European settlement. Our synthesis finds that fire use was highly localized and varied over as little as 10 km, indicating human ignition, as lightning-ignited fires are typically high-intensity and burn the forest canopy rather than understory. Our work demonstrates the utility of targeted, small-scale approaches in identifying the fingerprint of cultural fire use.