Coarse woody debris (CWD) biomass was measured and mapped in burned, clearcut, and intact lodgepole pine forests in two areas of the Rocky Mountains of Wyoming: the Medicine Bow National Forest (MBNF) and Yellowstone National Park (YNP). In addition, the amount of CWD consumed or converted to charcoal by fire was estimated in a recently burned stand in YNP. A spatially explicit simulation model (DEADWOOD) was then created to simulate the effects of various clearcutting and fire regimes on CWD over a 1000-yr period. Approximately 8% of downed CWD were consumed during a single fire and an additional 8% was converted to charcoal. After 1000 yr of simulation, 100-yr fire-return intervals produced CWD that occupied more of the forest floor than did 200- or 300-yr intervals. The time required for 100% occupancy of the forest floor by CWD was 1125, 1350, and 1300 yr for 100-, 200-, and 300-yr fire-return intervals, respectively. Simulations suggest that current harvest and post-harvest slash treatment regimes will require at least four centuries longer for 100% of the forest floor to be occupied by CWD (1800–3600 yr) than under fire regimes. This may have important effects on soil characteristics. Only when post-harvest CWD slash was doubled over the current amounts did clearcutting leave sufficient CWD to maintain forest floor CWD within the historic range of variability for naturally developing post-fire stands.