Forest insects

Trends in the area of moderate to severe defoliation (including beetle-killed trees) by insects in Canada. Monitoring forest area defoliated and damaged by insects is important to determine impacts to timber supply, the risk of fire, and the impact on the use of forests for recreational purposes or purposes related to other forest values. ^{Footnote 1}

Data table

Sources and information

Footnote 1

Source:

National Forestry Database. Forest insects, Table 4, Area of moderate to severe defoliation (including beetle-killed trees) by insects.

Notes:

Forest area disturbed by defoliators (e.g., budworms, spongy moth) includes only areas with tree mortality or moderate to severe defoliation. Defoliation does not always result in mortality. Several factors, including defoliation severity, duration and frequency, or presence of other stressors (e.g., drought), can affect the level of mortality.
Forest area disturbed by bark beetles (e.g., mountain pine beetle, spruce beetle) is derived from aerial surveys that map trees that are dead or dying from successful beetle attack.
Summing the areas affected by more than one insect to create a grand total can result in an overestimate if more than one insect species occurs in the same stand in the same year. For example, in a mixed wood forest, spruce budworm may defoliate balsam fir in the same stand where forest tent caterpillar is defoliating the aspen trees.

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Date modified:: 2025-03-14

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Forest insects

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