| Summary: | Tundra environments in Alaska are experiencing elevated levels of wildfire, and the frequency is expected to keep increasing due to rapid warming of the Arctic. Because of large amounts of carbon stored in permafrost soils, tundra wildfires may release significant amounts of carbon to the atmosphere that ultimately influence the Earth’s radiative balance. Therefore, accounting for the amount of carbon released from tundra wildfires is important for understanding the trajectory of climate change. We collected data in the Yukon-Kuskokwim River Delta during the summer of 2019 for the purpose of determining organic matter and carbon lost during the 2015 fire season. Organic matter and carbon lost from combustion were determined by combining burn depth measurements with organic matter and carbon content measurements from unburned tundra. Burn depth measurements were taken opportunistically across different levels of burn severity. Three vegetative markers, Sphagnum fuscum, Eriophorum, and Dicranum spp., that survived the fire event were used to measure the difference between the pre and post fire soil height in unburned and burned areas respectively, defined here as burn depth. All burn depth measurements are accompanied with coordinate locations so that they can ground truth and be upscaled by remote sensing data of burn severity. Organic matter and carbon content of the dense live vegetation layer and fibric soil layer were measured in the lab from vegetation and soil cores taken from four different sites in unburned tundra areas.
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