Forest fire affects the soil organic matter (SOM) pool through combustion, heating and deposition of residues.  Such changes could reduce the decomposability of SOM.  We examined how C mineralization rates of SOM are affected by fire severity using a model fuel bed from a ponderosa pine/Douglas fir forest. Temperature was monitored to determine severity.  O and A horizons were separated and incubated for 180 days.  CO₂ efflux was determined using a soda lime trap and cumulative CO₂-C released over time was fitted to a double exponential model to determine a labile pool (C0) and the mineralization rates of a labile (k) and a recalcitrant (h) pool.  Preliminary results suggest that as severity increases the mineralization rates of O horizon material decreases.  Mineralization rates from A horizons differ among the different severities depending on deposition of ash and temperature reached during the laboratory burning.  Forest fires may have impacts on the ability of forest soils to sequester carbon.