To reconstruct a natural fire regime it is necessary to estimate the historical fire cycle when human influence was less evident. This can be accomplished through the construction of a fire-origin map. The dynamic fire regime is a result of interactions among forest ecosystem components under various conditions. This paper examines the question of whether an ecological modelling approach could be helpful in providing a complementary solution for reconstructing natural fire regimes. Simulation of forest fire effects has been one component of the SEM-LAND model, and simulation results were validated by empirical observations from west-central Alberta, Canada. Model sensitivity analysis revealed that model behaviour was not influenced significantly by the initial forest age mosaic pattern and the critical value of daily precipitation that would be enough to stop a fire event. The methodology of simulating fire regimes is discussed. The ecological modelling approach could help forest managers evaluate proposed forest policy with emulation of natural disturbance patterns through harvesting. © 2000 Elsevier Science B.V. All rights reserved.