Pre-wildfire fuel reduction treatments result in more resilient forest structure a decade after wildfire

Increasing size and severity of wildfires have led to an interest in the effectiveness of forest fuels treatments on reducing fire severity and post-wildfire fuels. Our objective was to contrast stand structure and surface fuel loadings on treated and untreated sites within the 2002 Rodeo–Chediski Fire area. Data from 140 plots on seven paired treated–untreated sites indicated that pre-wildfire treatments reduced fire severity compared with untreated sites. In 2011, coarse woody debris loading (woody material >7.62 cm in diameter) was 257% higher and fine woody debris (woody material <7.62 cm) was 152% higher on untreated sites than on treated sites. Yet, in spite of higher levels of coarse woody debris on untreated sites, loadings did not exceed recommended ranges based on published literature and many treated sites fell below recommendations. By 2011, basal area and stand density on treated sites and stand density on untreated sites met management guidelines for ponderosa pine forests, but untreated sites had basal areas well below recommendations. Snags declined over this period and only three plots had snags that met minimum size and density requirements for wildlife habitat by 2011. The effects of pre-wildfire treatments are long-lasting and contribute to changes in both overstorey and understorey fuel complexes.