Forest disturbance arising from insect attack is a critical component of forest health. This module discusses the concept of forest health and categorizes the groups of insects in relation to the injury that they inflict on all the various parts of trees and the overall forest.
After viewing this presentation and relevant support material, users should be able to:
- Define and differentiate between abiotic and biotic forest disturbances.
- Explain the relative importance of insect disturbance in Canadian forest and recount several examples from the news headlines.
- Discuss the term forest health, and explain the functional definition that avoids value references
- Describe the two major guilds of tree herbivores and the two distinct types of development by insects.
- Differentiate between insect injury and damage.
- Describe the seven categories of insects and respective examples presented.
- Describe feeding and tree-injury characteristics of the mountain pine beetle; explain why this beetle is of such importance in British Columbia.
Listen to Dr. Allan Carroll respond to the question: How did I get interested in this area of study? by clicking on his photo.
For information about Dr. Carroll, please check UBC, Faculty of Forestry
Insects as Biotic Disturbance Agents
Dr. Allan Carroll explains how biotic (insects and disease) and abiotic (wildfire and wind) forest disturbances are related to forest health. Both native and invasive (non-native) insects are responsible for a relatively large portion of all forest disturbances in North America. Insects, which cause disturbance in forests through their herbivory on trees, are classified into seven major groups: sucking/galling; seed and cone; root and lower stem; shoot; woodborers; defoliators; and bark beetles.
- Tree Insects and Diseases of Canada’s Forests Database of ~300 insects from Canadian Forest Service, Natural Resources Canada
- Pine Beetle adds to CO2 problem. Canadian Broadcasting Corporation (CBC) news item on YouTube
- Insects and Diseases. Various articles, Canadian Forest Service, Natural Resources Canada
- Field Guide to Forest Damages in B.C. Ministry of Forests B.C. and Canadian Forest Service, 2001 Joint Publication No.17
Potential Questions for use by Instructors
- Explain the term “invasive species” using several examples from the presentation. Describe how such species threaten forest health (relate answer to functional definition of forest health).
- Choose a category of insects and describe an important species in this category. Explain how these types and specific species of insects affect trees, both in terms of injury and damage.