Theoretical fire-interval distributions

Models for fire interval distributions in ecological communities are propos ed, based on an understanding of the processes that influence the probabili ty of fire, especially changes to the amount and condition of the fuel. The models represent changes in the probability of fire as a function of time since last fire. Despite considerable differences in the probability distri butions of fire intervals, the models generate very similar age distributio ns when the mean fire interval is the same. Therefore, fitting the theoreti cal distributions to observed landscape age structure is unlikely to allow discrimination between different models. Previously, the most commonly used models of fire intervals have been based on the Weibull probability distri bution. We believe that this is unnecessarily restrictive, and a broader ra nge of models should be considered. The models may be based on an a priori understanding of the ecosystem being studied. They should assist interpreta tion of observed or inferred fire interval distributions.