Statistical and simulation modelling of boreal fire regimes

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Wildfires caused by lightning are a natural and regular occurrence in Canada's boreal forests. In many areas, they are one of the most important processes structuring this ecosystem. A "fire regime" is defined by the number, size, severity and time-of-year of the fires characteristic of a given region. The main goals of this research are to describe how fire regimes vary across the Canadian boreal and then to quantify the reasons for this variation. Of course, the broad outlines are well known: climate, for example is a main driver of fire. Large fires occur under warm, dry conditions. Thus, under climate warming, the average area burned per year is expected to increase in many parts of the boreal. However, it is becoming clear that vegetation also plays an important role. Different types and age of boreal forest have different potentials for fires to start or spread. If young forest, for example, inhibits fire, then fire must be to some extent self-limiting. Similarly, because forest management now manipulates the age-structure and species composition of large parts of the boreal, it too could influence future fire regime and, as one of my recent studies suggests, mitigate some fire-related effects of climate warming. Much of our recent data on boreal fires is collected by fire management agencies, whose mission is to put these fires out. The extent to which they have been successful remains unclear, and is of considerable interest in itself; however, to understand the effects of climate and vegetation, we need to understand also the effects of fire management, as reflected in the data we have and the forests we see today. Thus, the specific objectives of this research are to develop predictive statistical models that quantify the effects of all these factors on two aspects of fire regime: the number of fires, and the fire size distribution. I also seek new methods for linking these statistical models directly to spatial simulation tools, with applications to forest management and conservation planning. The direct beneficiaries of this work will be government agencies, industries and environmental organisations having responsibilities for or interests in the sustainable management and conservation of Canada's northern forests and wetlands.