Fire frequency and size distribution under natural conditions: a new hypothesis

Abstract

Decisions for sustainable forest resources management require a better understanding of forest dynamics as a result of disturbances. Forest fires are one of the major types of natural disturbances in many forest landscapes. Existing fire regime models can be used in evaluating the influence of a fire regime on landscape dynamics, but these models require users to define fire frequency and its size distribution as separate characteristics of a fire regime before running the models. By using a long-term spatial fire regime model, we tested the hypothesis that fire frequency and its size distribution are correlated with each other under natural conditions. Our study demonstrates that the hypothesis can not be rejected and the correlation between fire frequency and its size distribution was robust. Thus, the natural fire size distribution can be estimated when the fire return interval for a given forest landscape is known, if the natural fire size distribution can be approximated by a negative exponential probability distribution. This result simplifies the description of a fire regime from two parameters to one in some existing fire regime models. This simplification is limited to a ‘let burn’ scenario.