Assessing the Effect of Fire Regime on Coarse Woody Debris

This study used field data and modeling to examine how coarse woody debris (CWD) differs between two areas that experienced different fire regimes (120to 300-year mean fire return intervals) in the 1500-1850 period. Although fire frequency and severity established the overall pattern of CWD succession, the interaction of fire regime with other controlling factors caused the differences in CWD mass at the landscape scale. CWD mass was almost twice as high in landscapes having an infrequent, stand-replacing fire regime (173 Mg/ha) as in landscapes having a moderately frequent, mixed-severity fire regime (95 Mg/ha). Factors that appear to have the greatest influence are decomposition rates, fire severity, fire frequency, and fuel consumption, suggesting that environment and stand structure—together with fire regime—are more important than fire regime alone. CWD levels have greater temporal variability in the infrequent, stand-replacing fire regime than in the mixed-severity regime, primarily because of the different timing of mortality.