A spectroscopic approach for inferring charcoal concentrations and fire history from lacustrine sediments

Abstract

Current wildfire activity highlights the precarious ecological state of for- ests owing to the combined effects of climate change and management practices. Because the analysis of long-term fire frequency from sedimentary archives is critical to understanding fire dynamics, there is a continuous need to refine meth- odologies used to reconstruct fire frequency and intensity. Visible-near infrared (VNIR) spectroscopy offers a rapid and non-destructive method for remotely sensing charcoal concentrations from lacustrine sediment cores. In this study, a predictive model for quantifying charcoal concentrations from lake sediment absorbance was developed and subsequently applied to an 8000 year sediment record from Grand Teton National Park (Wyoming, USA). This record provides a detailed continuous fire history that captures regional fire trends obtained by optically counted charcoal from nearby lakes. The novel spectroscopic method for charcoal quantification reduces laboratory processing time tremendously and avoids various biases associated with conventional optical microscopic charcoal enumeration techniques.