Outbreak patterns of the spruce budworm and their impacts in Canada

Abstract

Historical records (1941–1998) of spruce budworm defoliation in Canada were analyzed to estimate variability in the spatial and temporal patterns of defoliation, and to determine 27 representative patterns that adequately describe the spatial and temporal variability in defoliation. Spatially referenced estimates of growth loss and mortality resulting from an outbreak of spruce budworm were obtained by subjecting a national forest inventory to the spatially defined representative patterns of defoliation. The use of these estimates in determining the status of Canada's forests as a carbon source or sink is discussed. Key words: spruce budworm, defoliation, growth loss and mortality, carbon source or sink