Forest management
Risk from Ips bark beetles can be reduced with well-timed thinning operations and quick removal of wind- or fire-damaged conifers.
During severe drought there is heightened risk for bark beetle infestation. We observed this in 1976, 1987, 1988, and 2021.
To reduce the risk of a Ips bark beetle infestation:
- Consider postponing pine harvesting operations until severe drought conditions are over, if possible.
- After severe drought, injury from fire, or blowdown occurring late winter through summer, monitor pines through the winter. Be prepared to salvage if you see widespread signs of infestation.
- For most harvesting operations, or after wind or fire damage, consider the following guidelines (the main objectives of these guidelines are (i) to reduce the risk of bark beetles attacking remaining conifers in or surrounding the harvest or damaged area and (ii) to help avoid blue stain fungi in pine lumber):
Time of damage or cutting | Action | When to take action |
February 1 through April 30 | Haul away logs more than 4 inches in diameter* | Before June 1** |
May 1 through August 31 | Haul away logs more than 4 inches in diameter* | Within 3 weeks of damage or thinning |
September 1-January 31 | May leave logs and slash on site*** |
* Bark beetles can survive in branches down to about 1 inch in diameter. The smaller the log’s diameter, the fewer beetles will reproduce in it. The 4-inch diameter limit represents the typical smallest diameter that is merchantable (inside the bark on the small end of the log). If hauling logs away is not possible, they could be chipped or burned (as long as nearby healthy pines aren’t damaged from burning).
** For areas in northern Minnesota, if March through May is colder than average, logs and slash can remain on site until June 15 without threatening residual pines.
*** Bark beetles can survive in branches down to about 1 inch in diameter. The smaller the log’s diameter, the fewer beetles will reproduce in it. The 4-inch diameter limit represents the typical smallest diameter that is merchantable (inside the bark on the small end of the log). If hauling logs away is not possible, they could be chipped or burned (as long as nearby healthy pines aren’t damaged from burning).
Yard trees
Preventing attack from Ips bark beetles is best. Keep trees well-watered during droughts. Water mature pines with a soaker hose at the canopy drip-line for several hours once per week during dry periods. After storm damage, promptly haul away pine debris (larger than one inch in diameter) to an approved facility, or chip up broken branches or snapped-off pines. Make sure fresh conifer firewood is never stored close to healthy conifers, since it can provide Ips bark beetle habitat.