BLACK CARBON ON COARSE WOODY DEBRIS IN ONCE- AND TWICE-BURNED MIXED-CONIFER FOREST

One important outcome of wildfire is the production of charcoal. Charcoal is highly resistant to decomposition and its physical and chemical properties enhance soil fertility and influence nutrient cycling. We compared the amount of black C (the carbon fraction of charcoal) on coarse woody debris (CWD; >= 7.6 cm diameter) and total CWD biomass at sites burned once in a high-severity fire with sites that burned in an initial high-severity fire and then reburned eight to ten years later. Twice-burned sites contained an average of 655 kg ha(-1) of black C on CWD, significantly more (P = 0.004) than the 323 kg ha(-1) present in once-burned sites. Total average CWD biomass was significantly greater in once-burned sites compared to twice-burned sites (P < 0.001). Black C accounted for 0.7 % of CWD biomass in once-burned sites and 2.9 % of CWD biomass in twice-burned sites. Short-interval reburns of patches burned in an initial high-severity fire increased the amount of black C on CWD while simultaneously reducing total CWD biomass.