Forest Health Monitoring in West-Central Canada in 1996

Results of forest health monitoring activities in Alberta, Saskatchewan, Manitoba, and the Northwest Territories are summarized for 1996. These results are based on assessments made on 17 permanent biomonitoring plots and assessments of major forest disturbances. Brief descriptions are given of major forest disturbances in the region, including forest tent caterpillar (Malacosoma disstria Hbn.), which defoliated 411 855 ha of trembling aspen forests; lodgepole pine dwarf mistletoe (Arceuthobium americanum Nutt. ex Engelm.), which causes severe disease on 428 541 ha of pine forests; spruce budworm (Choristoneura fumiferana [Clem.]), which defoliated 760 131 ha of white spruce–balsam fir forests; and forest fires, which destroyed 492 027 ha. Current climatic data from across the region are compared to 30-year normals for a number of parameters. Details of the assessments completed on the 17 permanent biomonitoring plots in the region are also given. Generally, tree condition of jack pine, lodgepole pine, white spruce, and trembling aspen on the biomonitoring plots was good, with most trees having less than 25% crown damage. Annual mortality rates were within the range of 0.4–3.3%. The state of regeneration on the biomonitoring plots is also discussed. Descriptions of the current status of quarantine pests in Canada of concern to the forestry sector are given.