Forest thinning and prescribed burning treatments reduce wildfire severity and buffer the impacts of severe fire weather

• DOI: 10.1186/s42408-023-00241-z
• Publication Date: 2024-02-07T08:02:45Z
• Authors: Emily G. Brodie; Eric E. Knapp; Wesley R. Brooks; Stacy A. Drury; Martin W. Ritchie
• Keywords: Thinning; Prescribed burn; Wildfire suppression

Abstract Background The capacity of forest fuel treatments to moderate the behavior and severity subsequent wildfires depends on weather conditions at time burning. However, in-depth evaluations how perform are limited because encounters between areas with extensive pre-fire data rare. Here, we took advantage a 1200-ha randomized replicated experiment that burned almost entirely in wildfire under wide range conditions. We compared impacts four fire severity, including two thin-only, thin-burn, burn-only, an untreated control. evaluated metrics—tree mortality, average bole char height, percent crown volume consumed (PCVC), affected (PCVA)—and leveraged from surface canopy fuels better understand mechanisms driving differences among they changed weather. Results found strong mitigating effects tree despite 20 years having elapsed since mechanical thinning 10 second entry prescribed fire. thin-burn treatment resulted lowest across all metrics control highest. All were positively associated loads, exception PCVC (a metric related behavior) was not load. which most effective varied metrics. Fuel benefit maximized intermediate burning index values for high PCVA, height PCVC. Conclusions conclude reducing bulk density via can help limit or more. is necessary scorching total mortality. Further, while effectiveness may decline severe it (bole charring torching). Our results provide evidence use mitigate resulting even extreme