Although forest management practices have been widely found to have negative effects on coarse woody debris (CWD), the long-term dynamics of these resources under partial harvesting systems in Ontario are poorly understood. I developed stage-based models of pine (Pinus strobus and P. resinosa) snag and downed woody debris decomposition over time. Using these decomposition models, a stand growth simulator, and data on the immediate impacts of harvesting and fire on CWD, I projected CWD accumulations in undisturbed pine stands, those subjected to periodic surface fires, and those managed under the uniform shelterwood silvicultural system. The modelled abundances of several types of CWD, particularly snags, were reduced at some or all points of the shelterwood harvest cycle relative to the other two scenarios. These simulation results suggest that additional management guidelines may be needed if adequate levels of specific CWD resources are to be continuously maintained in Ontario's shelterwood-managed pine forests.