Effect of recent prescribed burning and land management on wildfire burn severity and smoke emissions in the Western United States

Prescribed (“Rx”) fire is often proposed to mitigate future wildfires, but treatments remain limited, and few studies quantify their effectiveness on recent major wildfires. We investigate the effects of Rx fire treatments on subsequent burn severity across western US ecoregions and particulate matter (PM 2.5 ) emissions in California.

Using high‐resolution (30‐m) satellite imagery, land management records, and fire emissions data, we employ a quasi‐experimental design to compare Rx fire‐treated areas with adjacent untreated areas to estimate the impacts of recent Rx fires (Fall 2018–Spring 2020) on the extreme 2020 wildfire season. We find that within 2020 wildfire burn areas where Rx fires were used prior to 2020, burn severity changed by −16% ( p < 0.001) and smoke PM 2.5 emissions changed by −101 kg per acre ( p < 0.1).