Management of the mountain pine beetle

Although bark beetle outbreaks are natural disturbances in pine ecosystems in B.C., mitigation may be necessary when bark beetle populations threaten cultural, social, ecological, or economic forest values.

On this page:

• Detection 
• Strategies 
• Tactics

Detection

The two stages of beetle management detection are aerial surveys and ground surveys.

Aerial surveys

Surveillance-level aerial survey information is collected using the provincial aerial overview survey which serves to record the beetle damage at a low resolution and also identify new areas of attack. More detailed helicopter aerial surveys provide the spatial accuracy to direct ground crews to newly faded “red attack” trees to be surveyed.

• Annual data and summaries since 1999 are available in the AOS overview summary report

Ground surveys

Ground surveys are the most detailed level of detection and assessment data. Ground survey data is the best method to identify the appropriate tactics at the stand-level spatial scale.

Walkthroughs 

Walkthroughs confirm the previous or suspected identification of beetle and host, collect information to set further survey or management priorities, and estimate population trends.

Probes

Probes provide more detailed information than walkthroughs and may be appropriate for laying out treatment areas. These systematic strip surveys provide more precise estimates of attack levels, beetle trends and residual stand values. 

Star probes

Star probes can be used to quickly map the extent of beetle infestations for small scale rapid treatment.

Ground detection and monitoring using baited traps

To understand beetle presence and to know when beetles are flying, pheromone trapping for monitoring is recommended. Accurately knowing the beetle flight window is important to reduce the movement of infested trees during the period of time when beetles can attack new trees. For mountain pine beetle, traps should be deployed by June each year and checked weekly during the expected flight period.

Determining strategies

Measures for controlling the mountain pine beetle occur throughout the year. However, the insect's biology and the local climate determine when specific activities can be implemented. The timing of some activities must coordinate with subsequent activities. For example, probing must precede harvesting but must be carried out early enough that priority stands can be harvested before the next insect flight period. 

Factors that assist in determining potential management strategies include:

• Priorities
• Hazard ratings
• Risk ratings

Priorities

Not all forested lands with mountain pine beetle mortality require management. Numerous factors are considered prior to management action, including:

• Susceptible pine volumes at risk
• Beetle population size
• Access for harvesting
• Slope
• Other resource values
• Treatment resources

Hazard rating

Hazard rating identifies stands where substantial losses can be expected if an outbreak occurs. For mountain pine beetle this rating requires forest inventory data and inventory polygon location information. Data is collected from prism plots in the field to calculate the hazard index. 

Stands should be considered a high priority for hazard rating and management if they contain a high proportion of lodgepole pine 60 years and older and have elevation, latitude and longitude codes equal to high.

Risk rating

Risk rating estimates the probability of an outbreak arising, depending on a stand's proximity to an existing beetle population. It's determined by overlaying detailed sketch mapping and available ground detection results.

Tactics

To reduce beetle populations or reduce stand susceptibility to attack by mountain pine beetle, there are proactive and reactive stand management tactics. The selection of appropriate mitigation and management tactics depends on the local context and situation. Mitigation activities may not always be necessary, but when necessary, the following tactics could be applied for mountain pine beetle:

• Push-pull tactic
• Fall and destroy tactic
• Pest reduction harvesting
• Thinning to reduce susceptibility
• Planting for resiliency
• Retention areas for resiliency
• Anti-aggregation pheromones for high value trees