As the climate continues to warm, the frequency and severity of wildfires are expected to increase, altering global carbon stocks. Microbial communities play critical roles in carbon cycling and sequestration and increase the resilience of ecosystems. However, the effects of wildfire on soil microbial communities and the subsequent impact this perturbation has on ecosystem carbon stocks remains poorly understood. Here I investigate soil microbial communities present in the 2002 Hayman burn in Colorado to determine microbes’ role in building soil carbon stocks in a montane environment experiencing little post-fire recovery. Respiration in soils in two unburned watersheds was only ~14% greater (CO2 g-1 soil) than in soils in three burned watersheds, despite burned watershed soils having ~54% less carbon. Thus, soil organic matter (SOM) in burned watersheds is ~47% more bioavailable than unburned watersheds, likely due to differences in both SOM quality and the microbial community. Comparison of the δ13C of SOM and respired CO2 revealed that burned watershed SOM pools were smaller and more labile. Soil microbial community richness and diversity, determined using 16S RNA gene sequencing, illustrated that burned watersheds have soil microbial communities that are distinct from unburned locations, with specializations for utilization of fire-altered carbon pools. These changes were likely initially driven by changes in organic matter quality that affected microbial community establishment and thus mineralization. I therefore infer that microbial carbon processing forms a positive feedback that inhibits the accumulation of carbon stocks.