Forest management practices, such as clear cutting have been shown to disrupt the soil microbial ecosystem. Stable isotope probing (SIP) with 13C of specific biomarkers, such as PLFAs, is a promising new tool to directly link organisms with biogeochemical processes. We used this technique to study the fate of labeled litter and root material during decompostion in 8 and 26 year old clear cut forests in comparison to old growth Douglas fir forests at the Wind River Canopy Crane Research Station in SW WA. Incubation chambers with labeled materials at each stand age were destructively sampled over a 1 yr period. The results showed rapid incorporatin into PLFAs after one month's incubation. Fungal markers were highly labeled but the degree of labeling varied over the year with lowest 13C incorporation during the dry period in August. The 8 yr clear cut had higher fungal labeling than the other stand ages suggesting the importance of fungi in sequestering C after the distubance of clear cutting.