WILDFIRES IN THE WESTERN CANADIAN BOREAL FOREST - LANDSCAPE PATTERNS AND ECOSYSTEM MANAGEMENT

Mimicking of natural disturbance for ecosystem management requires an understanding of the disturbance processes and the resulting landscape patterns. Since fire is the major disturbance in the boreal forest, t hree widely held beliefs about fire behavior and resulting landscape p atterns are examined in Light of the empirical evidence available. The se beliefs are: (1) that there is a 'natural' fire frequency for borea l ecosystems; (2) that the landscape mosaic created by wildfire is gen erally one of small, younger patches embedded within a matrix of older forest; and (3) that forest flammability is largely controlled by fue l accumulation. Despite the apparently logical basis for such beliefs, they are not well supported by empirical evidence. This discrepancy i s explained by problems such as failure to appreciate the relationship between number of fires and area burned and inappropriate extrapolati ons or generalizations from other regions and vegetation types. The mo st important implications for management are that the natural disturba nce processes producing landscape patterns in the boreal forest genera lly operate at much larger scales than management units, and that huma ns may have more indirect (through landuse change) rather than direct (through fire suppression) effects on the frequency of wildfires.