Pesticide applications may not be logistically or financially practical on a forest level, so sound silvicultural practices that increase the overall health of the forests are important.
Maintaining good tree health and vigor as well as swift cleanup and processing of dying or recently downed spruce trees are keys to reducing the likelihood of spruce beetle population buildups in your spruce forests. In times of high spruce beetle populations though, these efforts may not be sufficient to prevent spruce beetle attacks.
Preventive tactics for spruce beetle include pruning individual trees and thinning dense forest stands. These tactics can increase the overall vigor of the remaining trees while allowing more light and air movement around the lower portions of the trees. Preventive tactics are most effective when spruce beetle populations are not elevated and are unlikely to prevent spruce beetle attacks during an outbreak.
When working in and around your forest stand, avoid damage to live standing spruce trees. Damage to the trunk and roots from land clearing, logging, soil compaction or other ground disturbance where roots are impacted, domestic animals, ATVs, and other stressors can predispose trees to bark beetle attacks.
In large acreage forests, conducting a forest health assessment is recommended to help you determine the need for mitigation treatments and to prioritize where treatments may be most effective. Please contact the Forest Health Program with the Alaska Division of Forestry & Fire Protection for information regarding assessing forest health.
If spruce beetle populations are elevated in your area, there are a few options that can decrease the number of active beetles in an infested forest, providing some protection of your remaining spruce trees.
Sanitation Harvest
In forests that currently have spruce beetle infestations present, the best course of action is a sanitation harvest. A sanitation harvest means that you would harvest and process any damaged, dying, recently dead or down, and actively infested spruce trees. Review the Identification section of the website for information on how to determine if a tree is infested. Keep in mind that trees containing active beetles may still be green.
Harvested trees may be merchantable for forest products. Past studies have determined that beetle-killed spruce in Southcentral Alaska are most valuable for lumber within 3 years of being attacked. However, these trees may remain useful for pulpwood, house logs, and firewood for considerably longer.
All white, Lutz, or Sitka spruce harvest practices where live, dying, or recently dead trees are cut, should be done outside of the spruce beetle flight period (May-July), when possible. Additionally, these felled trees should be processed as soon as is reasonable and ideally by the following spring after harvest. Processing can consist of debarking, milling, processing for firewood, chipping, burning, or burying. Please note that all burning must be done in accordance with applicable regulations. For more information visit the Alaska Division of Forestry & Fire Protection’s website for burn permits and restrictions.
More details on these and other options are available from the Alaska Division of Forestry & Fire Protection-Forest Health Program.