Mapping Forest Carbon Stocks to Understand Carbon Implications of Treatment on Wildfire for the Calwood Fire, Boulder County Colorado

Recent, record-breaking wildfire activity in the western US illustrates the need for fire mitigation, such as forest fuels reduction treatments and prescribed fire. Forests serve as crucial carbon sinks that combat the increasing effects of climate change but fuels reduction treatments may remove carbon from forested systems. As a result, forest managers are seeking a balance between fire mitigation and carbon preservation. This project investigated post-fire carbon stocks in treated and untreated areas of the 2020 Cal-Wood fire in Boulder County, Colorado. Using remote sensing data from Landsat 8 Operational Land Imager, Shuttle Radar Topography Mission, Sentinel-2 MultiSpectral Instrument, and LiDAR, we mapped post-fire forest carbon pools and compared these values with field measurements. Post-fire carbon stocks and distribution across live and dead pools were compared between untreated areas, areas that burned in recent wildfires, and areas that were thinned and/or prescribe burned before the fire. Carbon maps were most accurate for the aboveground live carbon pool (R2 = 0.76) followed by the aboveground dead carbon (R2 = 0.44) pool, and provided a fire-wide estimate of how fire redistributed forest carbon between the live and dead carbon pools. Our analysis suggested that fuels reduction treatments did not reduce aboveground live carbon loss in the presence of wildfire enough to clearly distinguish post-fire carbon between treated and untreated areas. This method provides a promising approach to understanding how fires of various severities influence forest carbon stocks, and to evaluate the effect of pre-fire fuels treatments on carbon.