About insects and diseases

Boreal forests are disturbance-driven and insect and disease outbreaks often occur on a large scale. These natural disturbances are essential to the productivity and renewal of forests.

Insects

Insects are an important variable in the life cycle of the boreal forest. Large insect outbreaks that occur regularly help to renew the forests. Insects release nutrients stored within trees. Infestations also eliminate sick and aging trees, reducing competition among trees and making the ecosystem more productive. Insects found in NWT forests include: 

• aphids
• birch leafminer
• bronze birch borer
• bruce spanworm
• forest tent caterpillar
• large aspen tortrix
• mountain pine beetle
• spruce budworm
• spruce spider mite
• white pine weevil
• wood borers in hardwoods
• yellow-bellied sapsucker (bird)
• yellow-headed spruce sawfly

Diseases

Diseases contribute to the forest ecosystem by speeding up the mortality of weak and over-mature trees, clearing the way for forest renewal and increasing biodiversity. Diseases also break down dead plant material, a process that recycles nutrients and organic matter. Root diseases are among the most common in boreal forests.  Forest diseases found include:

• armillaria root disease
• cooley spruce gall adelgid
• fire blight
• poplar bud gall mite
• spruce needle rusts
• western gall rust