ACCOUNTING FOR PYROGENIC CARBON STOCKS IN THE CACHE LA POUDRE WATERSHED FOLLOWING THE HIGH PARK FIRE
Soil C stocks were highly variable post-fire and ranged from 8.7-17.7 tC ha-1 in the ponderosa pine 0-5 cm soil. The high burn intensity tended to have lower soil C stocks compared to the moderate and unburned soil. Interestingly, in the burn sites (moderate and high) the steepest slopes tended to have higher soil C stocks. BPCA results indicated low slope aspect (0-5°) always retained more PyC than higher slope aspects (5-15°) regardless of burn intensity. In the low slope aspects soils, however, the amount of PyC at different burn intensity followed the opposite pattern from what we expected, with high burn intensity having the lowest amount of PyC and the unburned sites with 50 to 400% more PyC. High amounts of PyC in unburned soils could be from previous fires, or from atmospheric deposition of PyC from burned areas to unburned sites. Additionally, low amounts of PyC in high burn intensity sites may be due to losses from wind transport or combustion of residual PyC during the High Park fire. Our initial results illustrate the importance of quantifying PyC in soils with different characteristics (e.g. burn intensity, slope), and how this type of accounting can lead to descriptive dynamics of PyC within the global C cycle.