COPING WITH UNCERTAINTY IN FOREST WILDLIFE PLANNING

Forest planning rarely incorporates uncertainty about the incidence of disturbance and how ecosystems respond to disturbance. This omission may bias perceptions about the impact of disturbance. Human impacts, such as timber harvesting, are often deterministic, with disturbance occurring at prescribed intervals, at a single spatial scale, and at a single intensity. Such deterministic processes are likely to have very different impacts from natural stochastic processes that operate at random over a range of spatial and temporal scales. It is insufficient to describe disturbance in terms of mean values such as frequency, because variation around the mean is important for determining the impact of disturbance. Uncertainty is ubiquitous in natural systems and the importance of including uncertainty in forest management is discussed. Methods are described for integrating uncertainty of various types into forest planning, while accounting for timber and wildlife values. The methods involve placing bounds on predicted impacts of disturbance and determining probabilities of extreme events.