Spruce Beetle in Alaska's Forests

Processing wood from beetle-killed trees

Removal of infested material

Infested trees in landscapes should be removed quickly to

  • minimize the possibility of beetles infesting nearby trees and
  • minimize the risk of the dead tree becoming a safety hazard on the property

Infested trees in forest stands can be removed to

  • remove beetle pressure in the area
  • improve resiliency of the surrounding forest stand

While beetles can come to an area from a variety of places, an infested tree can become a population source for future infestations. A tree that has died due to spruce beetle may have emerging adults for up to two years following its death. Those adults may seek nearby trees as hosts. Felling the tree and either removing the material from the area or processing it can help reduce spruce beetle populations in an area. Several considerations should be made when deciding to remove a tree.

When to cut

Whether you are removing an infested, dead tree or clearing a lot for construction, avoid felling trees during the spruce beetle active flight period (May-July). Fresh host material during this time is attractive to the beetles and could pose a risk for standing trees. If trees must be removed near or during this time, proper care should be taken to process or destroy the material quickly.

After a tree has been felled, make sure to cut the stump as close to the ground as possible or have it ground down as this material can also serve as spruce beetle habitat.

What to do with the wood

If you do not intend to keep or use the infested material, several communities have woodlots associated with solid waste disposal. If the woodlots regularly chip or burn material these are good places to take spruce beetle infested material if you do not intend to use the wood yourself. If your community does not have a woodlot and someone else is taking the material, make sure they know that the material is infested and the steps they can take to minimize the risk to trees on their property.

If you are not removing the material from the area, several processing strategies are available to reduce spruce beetle populations. Generally speaking, a main goal of processing is to speed up the time it takes the material to dry out. Dry material becomes less suitable for spruce beetles. Felled trees can be cut into smaller lengths, split, and loosely stacked. Removing the bark from the tree to reduce beetle habitat and expose the insects to drying out is also a very good strategy. This can be difficult and time consuming and is not practical on a large scale but may make sense for individual trees. Removing the bark can be done by hand using a drawknife or debarking spade.

Infested material intended for use as firewood should be burned before the following spring. More information on using infested material for firewood is found in the Firewood Considerations section.

Infested material can also be buried with at least 8 inches of soil covering it. This may not be a possible or practical solution for all situations.

Sanitation practices

Sanitaion after a windstorm or tree removal is important to manage spruce beetle populations in an area. After wind events, debris and damaged trees should be cleaned up quickly to remove host material. Material that is saved to be used as firewood should be treated as described above for felled trees and below in the Firewood Considerations section.

Any outdoor burning of residual materials should be done in accordance with all local and state regulations.

Firewood Considerations
Spruce trees killed by spruce beetle make useful firewood, but care should be taken to prevent moving an infestation from one area to another or increasing a problem in the immediate area. Both standing trees and felled trees may harbor spruce beetle lifestages and should be inspected before moving them to a new location. Check the exterior of the tree for the signs and symptoms of spruce beetle described in the identification section. On already dead trees, peel back the bark to look for spruce beetle life stages. Remember there are lots of similar beetles that can live under the bark of trees. For trees that have current spruce beetle infestations good general guidelines for firewood include:

  • Store enough firewood for a single winter’s use
  • Split and debark material to increase air circulation and reduce beetle habitat
  • Stack firewood loosely
  • Do not stack spruce firewood against living spruce trees

Whether you are collecting firewood from private property or within state or federal lands (permits required, contact your local Division of Forestry or Forest Service office for more information), below are some guidelines to help determine the best way to process spruce material to prevent spreading a spruce beetle infestation in the area or at your home.

Know the condition of the tree:

Living trees with green needles and no evidence of spruce beetle infestation when felled:

If you are clearing land and removing living, unattacked trees, you could potentially attract beetles to the area due to an abundance of host material. Avoid doing this kind of cutting during the adult flight period (May to July). If possible, complete this work in the late fall, winter, or early spring. If the cutting must be done during the adult flight period, the following best practices should be employed:

  • Cut logs into shorter lengths, split, and loosely stack in sunlight to increase the speed that the material dries out.
  • If feasible, remove the bark from the logs before stacking.
  • Use the material as soon as possible or only store enough wood for a single winter’s use.

Living trees with green needles, obvious signs of spruce beetle infestation on trunk:

Be very cautious about bringing known infested material to a new location.

  • Remove and destroy the bark to remove larval habitat and speed up the drying process.
  • Logs should be cut into stove-length pieces, split, and loosely stacked to promote drying.
  • Store only enough wood for a single winter’s use.

If you have brought firewood home before realizing it was infested, you may want to consider a preventive treatment for standing live trees on the property if the wood was brought in before or during the adult flight period (May –July), you have more wood than you will use before the following May, or you already have spruce beetle issues in your area. Preventive treatments using pesticides should be done following the guidelines in the pesticide section above. Any treatments should be done ONLY on live, unattacked trees. There are no pesticides available for treating firewood infested with spruce beetle.

Recently dead trees with red or brown needles mostly still on the branches. Branches still outright from tree. Some evidence of spruce beetle attacks:

Be very cautious about bringing known infested material to a new location.

  • Remove and destroy the bark to remove larval habitat and speed up the drying process.
  • Logs should be cut into stove-length pieces, split, and loosely stacked to promote drying.
  • Store only enough wood for a single winter’s use.

Dead trees, no needles attached, branches “droopy”:

These trees have been dead long enough that they are no longer attractive host material for spruce beetles and any spruce beetles that may have used the tree have completed their life cycle and left. This material can be processed and used without worry. Keep in mind there are other insects likely in this material. These are usually decomposers and pose little to no threat to standing live trees.