Unit 5 - Forest Protection

Lesson 5: Forest Pest Management

In the past, Canada has used tactics such as pesticide application and accelerated rates of harvesting to manage pest outbreaks in our forests. However, many pesticides are harmful to the environment and have been prohibited.

Biological agents are preferred because they generally affect only one or a few pest species. For example, Bacillus thuringiensis (also known as B.t.) is used against the spruce budworm. It is a naturally occurring, host-specific bacterium that is environmentally safe. Research and technology continue to provide forest managers with useful tools in the fight against forest pests. For example, researchers at the Canadian Forest Services' Laurentian Forest Centre have developed a software tool called BioSIM. This tool links weather data with information related to the pest's biology. This allows forest managers to conduct pest control activities at the optimum time. For example, in 1999-2000, British Columbia engaged in extensive spraying against the gypsy moth. Timing of the spraying was to have happened as soon as leaves had developed to half their full size. However, BioSIM predictions indicated that caterpillars would not have begun feeding by that time. Without this critical information, spraying would have started too soon.

Going forward, Canada can expect to see more frequent and widespread pest infestations, with Alberta being no exception.
Aging forests and climate change are two of the main reasons for this trend:

Alberta's forests are aging. This is largely due to recent successes at fighting forest fires.
In fact, according to Alberta Sustainable Resource Development, over 80% of Alberta's deciduous, pine, and white spruce forests will be over-mature within the next thirty years, if present trends continue. This is significant because aging forests are more susceptible to insects and disease.

Climate change is allowing many forest pest species in North America to expand their ranges into more northern regions. One of these forest pests is the mountain pine beetle (MPB), the most significant insect pest attacking the mature pine forests of western North America.
The mountain pine beetle peaked at epidemic levels in British Columbia in 2004, where it killed 140 million cubic metres of merchantable pine forests. The annual kill then declined rapidly and recent computer modeling projections indicate about 57% of B.C.;s pine volume killed by 2021. This is significantly less than the 80% pine kill in 2007.

Alberta's forests are also under threat as the mountain pine beetle spreads further north in Alberta. In the past, cold winter temperatures helped to limit the survival of the MPB. However, recent mild winters and hot, dry summers have enhanced development, dispersal, and survival of this insect pest.

As you go the website "British Columbia's Mountain Pine Beetle", please keep in mind the questions below. These questions pertain to the video (found at the end of this web page) and need to be answered on the Unit 6 quiz:

  1. What kind of tree is attacked by the Mountain Pine Beetle?
  2. How has more effective control of forest fires contributed to the outbreak of the Mountain Pine Beetle?
  3. Describe two ways in which climate change also contributed to the mountain pine beetle outbreak?
  4. Name two ways in which forest managers are slowing down the spread of the mountain pine beetle in areas in which there are large numbers of infected trees.