Sustainability of timber supply considering the risk of wildfire

Abstract

The boreal mixedwood forest of Alberta, Canada is an important timber-producing region subject to highly variable annual disturbance by wildfire. Existing timber supply models do not adequately capture the variation in annual area burned. This article presents a procedure to evaluate the joint effects of harvest levels and wildfire on the sustainability of timber harvest. A Monte Carlo simulation model is developed that incorporates timber harvesting, forest fires, and replanning. The output of the model consists of projected distributions of sustainable harvest levels generated by a linear programming-based timber supply model in response to specified harvest volumes and randomly generated burn areas. Because of the highly variable nature of the fire regime, it is difficult or impossible to set a harvest level that is perpetually sustainable with complete certainty. An alternative definition of sustainability is developed incorporating probabilities and time. At any point in time, a harvest level is considered sustainable if the probability of the harvest level exceeding the annual allowable cut is less than an acceptable level.