24-16 A c. 13,000-year Record of Wildfire Activity from Ossipee Lake, New Hampshire

Session: Lake Sedimentary Records of Past Climate and Environment (Posters)

Poster Booth No.: 44

Presenting Author:

Lucy Whitelam

Authors:

Whitelam, Lucy¹, Balascio, Nick², Cook, Timothy³, Tsalickis, Alexandra⁴, Vachula, Richard⁵, Karmalkar, Ambarish⁶, Snyder, Noah⁷

(1) Earth and Climate Sciences, Bates College, Lewiston, , (2) Earth and Climate Sciences, Bates College, Lewiston, , (3) Department of Earth, Geographic, and Climate Sciences, University of Massachusetts Amherst, Amherst, , (4) Department of Geosciences, Auburn University, Auburn, , (5) Department of Geosciences, Auburn University, Auburn, , (6) Department of Geosciences, University of Rhode Island, Kingston, , (7) Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, ,

Abstract:

Examining fire activity in response to natural climate changes of the past is key to better understanding future fire dynamics. Sedimentary charcoal records can be used to pinpoint past fire events within a watershed and document long term regional trends in fire activity. In this study, we present a c. 13,000-year paleofire record from Ossipee Lake in central New Hampshire. Charcoal particles (>125 µm) were counted and charcoal morphologies were quantified by using image analysis software integrated with a transmitted light microscope. Trends in the morphometry of the particles including: aspect ratio, area:perimeter ratio, roundness, and circumference were analyzed to infer changes in the source of charcoal. Additionally, select charcoal samples were imaged using a scanning electron microscope to determine the vegetation types of the burned material over the Holocene. Charcoal accumulation rates show elevated fire activity from c. 5,600-10,100 cal yr BP and two large peaks, c. 10,100 cal yr BP and c. 8,300 cal kyr BP. Generally lower charcoal accumulation rates define the last c. 5,600 cal yr BP, although elevated values are observed from c. 1000-700 cal yr BP. Greater fire activity in the early Holocene does seem to be supported by other records, but few exist in close proximity to our site. This study contributes to our understanding of the northeastern United States fire history.  Ongoing work will examine the connections between fire activity, changing climate, human activity, and vegetation throughout the region to better understand the drivers of these trends.

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