Fire impacts and crowning in the boreal forest: study of a large wildfire in western Quebec

Within the context of studying the ecological impacts of wildland fires in the boreal forest, a spatial analysis of a major wildfire was conducted. Th e fire covered nearly 500 km(2) in the north-western part of Quebec's borea l forest in the summer of 1995. The spatial distribution of different fire impacts on the forest canopy was obtained using timber damage assessment ma ps. Fire impacts varied throughout the burned area, ranging from areas wher e trees had completely burned crowns (43%) to remaining patches of trees wi th green foliage (3%). The effects of local stand and site factors on crown fire, as assessed by the fire impacts, were evaluated using geographic inf ormation systems. Despite the large extent and high intensity of the wildfi re created by extreme fire weather conditions, stepwise logistic regression and analysis by log-linear models indicated that variations in surface mat erial, stand composition, and estimated stand age played a role in the pres ence or absence of crowning at the stand level. However, it appears that he ight and density of stand, as well as topography, did not have a significan t influence. Our study presents the variability of fire impacts and its imp lications, and it provides a better understanding of the relationships betw een landscape components and fire crowning.