Risk-based decision making

Canada’s approach to forest pest management has traditionally involved direct interventions such as pesticide spraying and accelerated salvage harvesting.

Today direct interventions are still used, though increasingly as part of an integrated, risk-based approach to pest management.

Risk-based decision-making recognizes that major outbreaks of insects and diseases in Canada’s forests pose a wide range of significant economic, social and ecological risks, all of which must be considered when forest management actions and investments are being decided. Attempting to eradicate some outbreaks, for example, may end up being highly costly but still unsuccessful—or worse, results in unintended outcomes that lead to new problems.

Making the best decisions around forest management issues therefore requires a full risk analysis first so that the likely outcomes of a range of actions can be better assessed and compared. This approach is central to Canada’s National Forest Pest Strategy.

Dealing with uncertainty

Making forest pest management decisions always requires addressing uncertainty. Gathering new evidence to reduce uncertainty is a fundamental element of risk analysis.

For example, through surveys, researchers may obtain sufficient evidence to show that an insect outbreak is imminent. Using this information, forest managers can then estimate the type and degree of risks with greater certainty.

Risks associated with invasive alien insects and diseases are especially uncertain because of the novelty of the ecological situation and the possible lack of options initially available for control.

The role of the CFS in risk analysis

The main role of the Canadian Forest Service (CFS) in risk analyses is as a key source of historical and current scientific knowledge about Canada’s forest insects and diseases.

As well as scientific knowledge, CFS offers risk evaluation expertise and tools for estimating and predicting risk. The forecasts resulting from this work can be used in several ways—for example to examine the potential range of an alien species, provide optimal timing for application of pesticides, or inform managers about the locations of future hazards.

Pest outbreaks cause significant growth loss and mortality in forests across Canada. When outbreaks occur, large uncertainty results about the future structure and productivity of the affected forests.

Two examples of tools developed by the CFS to help forest managers make risk-based decisions:

• The CFS, building on research about spruce budworm impact, has developed the Spruce Budworm Decision Support System. Using forest inventory data, budworm monitoring data and other information, this tool calculates how a range of different pest management options would affect the timber supply. Resource managers then incorporate the projected effects of insect damage into their forest management plans.
• BioSIM is a software tool developed by the CFS for forecasting the seasonal occurrence of insects and other organisms. BioSIM’s simulation models take regional air temperature and precipitation data recorded at weather stations near the infested forest area, and integrate that data with knowledge about how those weather factors affect the organisms’ life history. BioSIM has been used, for example, to forecast the development of populations of spruce budworm, gypsy moth, eastern hemlock looper, jack pine budworm and yellow-headed sawfly.
  An organization that is monitoring or managing forest pests can use the information generated by BioSim for such operations as optimizing plans for sampling and surveying, applying pest control products, and evaluating changes in the potential range of organisms.

Efforts aimed at reducing risks of forest pest damage

Forest pest research at the CFS has included developing a range of biological and forest management tools and techniques aimed at reducing the establishment, spread and damage of undesirable insects and diseases. Examples are:

• Developing new control products that target the behaviour of a pest: Among these products are semiochemicals, which are natural chemicals (such as pheromones and repellents) that carry a message between or within species.
• Developing new methods to detect and control insect and diseases: For example, CFS researchers have developed molecular diagnostic kits that identify the pests currently posing the greatest threat to Canada’s forests. One such kit now enables forest managers to monitor the growth and spread of the invasive micro-organism that causes sudden oak death.
• Breeding disease-resistant varieties of trees to replace the trees lost to pests: This is a strategy, for example, that might help save the endangered butternut tree in Ontario, Quebec and New Brunswick. The species is threatened by butternut canker, an introduced fungal disease.