Unit 5 - Forest Protection
Lesson 4: Insect PestsNative insects and diseases play an important role in the health of the forest ecosystem in Canada; they are usually classified
into 3 categories.
Examples are the spruce budworm, tent caterpiller and the mountain pine beetle.
Examples include the emerald ash borer, the brown spruce longhorn beetle, and Dutch elm disease.
The spread of mountain pine beetle from British Columbia’s lodgepole pine forests to Alberta’s jack pine forests is an example of a native forest insect behaving invasively.
- removing old or susceptible trees
- recycling nutrients
- providing food and new habitats for wildlife
When insects severely infest an area, destroying large areas of forest or forest products, they are then known as pests.
A healthy tree can usually withstand an insect outbreak with minimal effect, but if the tree is weakened or stressed, the consequences of an insect infestation may be more serious.
If the insect pest is alien, the tree may have little or no natural resistance to it. This allows non-native species to do a lot of damage and spread quickly.
The major forest insect pests in Alberta's forests are the defoliators and the bark beetles; they significantly disturb forest ecosystems.
Defoliators feed on the tree's leaves. The spruce budworm and the forest tent caterpillar are two such pests. These defoliators consume part or all of the leaves of the tree that they are infesting.
The mountain pine beetle, the most damaging insect pest of pine trees in western North America, has devastated British Columbia forests and is now posing a serious threat to Alberta's forests.
From 1998 to 2008, the mountain pine beetle killed approximately 620 million cubic meters of pine in British Columbia, almost half of the province's commercial pine.
Click here to read about the devastation the mountain pine beetle has caused in Alberta.