Deal properly with wind-damaged spruce

Thousands of trees blew down during last winter’s windstorms and heavy snows in the Interior and in Southcentral. Windblown spruce, birch and cottonwood trees were found this spring along highways, in yards and open areas, and within the forest.

Last December, a storm leveled hundreds of mature white spruce and birch along the Parks Highway between Trapper Creek and Byers Lake.

Many spruce growing in moistened soil from rain last fall were tipped over, root wad and all. Others snapped off above the stump, indicating that root rot and ant damage had weakened tree trunks.

Delta Junction had an early winter wind of more than 80 miles per hour, and Glennallen reported wind damage and trees bent with snow this spring. Many uprooted and damaged windthrown trees prove to be diseased, insect-injured, large, top-heavy or just old. Several people have contacted the University of Alaska Fairbanks Cooperative Extension Service to find out what to do with these damaged trees, which can attract insects, including the spruce beetle.

Each year, wind and snow bending occurs within the forest. As the forest ages, disease, root and stem rot, ant infestation, shallow rootedness, wet soils and heavy snow loads may cause this natural forest thinning. Given the incidence of fire, insects, wind and heavy snowstorms, it is not easy being a green tree in the Alaska boreal forest. Thick spruce needle foliage catches the wind more easily than adjacent birch trees that have lost their leaves.

Landowners should check their property for wind-damaged trees each spring. Spruce trees connected to the soil by the root wad are more apt to attract spruce beetles than spruce snapped clean off. But both types of windthrown spruce act as a beetle magnet. Tipped-over spruce trees with their root wads connected continue to cycle nutrients and moisture, providing succulent inner bark to infesting spruce beetles. These trees have no hope of fighting off beetle larva and they will never overcome their downed position.

The best treatment is to cut them up and haul them out of the woods this summer. Scatter your branches to dry in the sun or pile them if you like. Beetles won’t be a problem in the branches. You can leave your firewood-sized spruce in the woods and it will attract beetles, but they usually can’t mature to become breeding beetles because the chunks of firewood dry faster than beetles can mature. Spruce cut into firewood will dry faster than logs.

Move cut logs out of the forest as soon as possible. Store them in a sunny location away from your standing spruce. Pile them as is safely practical and cover with a tarp. A roll of Visqueen plastic works well, too. Covering will cook the beetles under the plastic or tarp in the sun and they won’t be able to mature and fly out of your logs. You may see the larger longhorned beetles. These pesky, wood-boring beetles infest logs and dead spruce, but they won’t kill your adjacent spruce.

Windthrown spruce trees, and those left after construction, create conditions for infestation in an otherwise healthy forest. Spruce logs and downed trees are much more prone to infestation and become a point of infestation by spruce beetle in the adjacent healthy forest. You can use your downed spruce as “trap trees.” They will capture beetles that infest your logs, but only if they are cut up and removed before the new beetles emerge. Cut up, dry out and remove each year’s windblown spruce. You’ll have better firewood next winter, too.

Glen Holt is the eastern Alaska forester for the University of Alaska Fairbanks Cooperative Extension Service. Contact him at (907) 474-5271 or by email at ggholt@alaska.edu.