Forests play an important role in sequestering atmospheric C (i.e., carbon dioxide -CO2), much of which has resulted from increased anthropogenic C emissions. Reducing atmospheric CO2 levels is essential for mitigating potential global climate change impacts. The extent of the role of forests in this process is dependent not only on the forest type, cover and location but also on forest management practices. We evaluated the effects of four different forest management practices on C and N pools in a ponderosa pine (Pinus ponderosa) ecosystem located in the Black Hills, Wyoming. The different management practices resulted in stands that were 1) even-aged, 2) uneven-aged, and 3) heavily harvested, which were compared to an unmanaged (control) stand. Aboveground C pools (i.e., downed wood, live trees, saplings, herbaceous, standing dead trees, stumps coarse wood, and forest floor) and belowground C pools (i.e., fine root biomass and mineral soils to 60 cm) were estimated. Total aboveground C was significantly higher in the control stands than in the managed stands (P< 0.05), indicating an effect of various management practices on aboveground C pools. However, no significant differences were found among management practices in terms of total soil and root C, but total soil N was high in managed stands than the control site. Higher total N concentrations of managed sites may be attributed to release of nutrients including nitrogen by decomposition and mineralization of plant litter such as harvest residues and understory litter.