Causes and Impacts

Last Review/Updated: January 6, 2003

Exotic forest pest species are becoming more of a threat to Canada and ultimately to Alberta partly because of the following reasons:

  • World trade has expanded;
  • Only a small percentage of imports are inspected;
  • A lot of imports are shipped directly to the destination bypassing inspection points;
  • Untreated wood is the cheapest packaging material available and is widely used;
  • Wood packing materials are improperly disposed;
  • Many exotic pests are difficult to regulate because they come in as "hitchhikers" and have nothing to do with the imported commodities;
  • Many exotic pests can enter Canada/Alberta at any point along the transportation route;
  • Firewood with the bark still attached is being transported throughout North America;
  • Free trade has resulted in increased volume of plant materials freely moving across the borders;
  • The public is unaware of the dangers of exotic pests and unknowingly ship or carry these pests.

Main Causes

The following identifies the main categories of exotic pest introduction:

  • Introduced intentionally and escaped.
    • Most of plant and vertebrate species were introduced for their economic and social values and even sentimental values.
    • e.g. Starling, gypsy moth, toadflax, purple loosestrife
  • Accidentally introduced with their host species.
    • Most of invertebrate and microbial species
    • e.g. Dutch elm disease, chestnut blight, white pine blister rust
  • Hitchhikers
    • Alarming number of new hitchhikers are forest/tree pests
    • e.g. Norway rat, Asian long-horned beetle, Asian gypsy moth

Pathways

Exotic pests can enter Canada and thus Alberta in many ways. According to the Canadian Food Inspection Agency, the following are the most common pathways for exotic pests to cross our borders:

  • Containers;
  • Forest Products with Bark;
  • Vegetation Nursery Stock;
  • Soil;
  • Solid Wood Packing Material (crates, dunnage, and pallets);
  • Ships and Other Transportation Vehicles.

In Alberta, forest products with bark, nursery stock and wood packing material are the main ways that exotic forest pests enter the province. To reduce the impact of exotic species being imported in wood products, the Canadian Food Inspection Agency has new directives that specify the import treatment requirements of wood products from areas other than the continental United States.

Impacts

Because Alberta is relatively free of exotic species and detection of problems takes time, Alberta's native vegetation is threatened by invasive forest pest species. Having evolved in a different ecosystem, these non-native species may have few natural enemies, often leading to outbreak populations and destruction of native species. The overall consequences can affect the economy, social value and environment of Alberta in the following manner:

  • Economy:
    • Direct loss of trees;
    • High pest control costs, including detection, monitoring and control;
    • Public health issues;
    • Trade barriers with other countries.
  • Social values:
    • Decline of property values;
    • Negative impact on overall viewscape.
  • Environment:
    • Loss of habitat;
    • Endanger native species.