Box
310, Dillingham, Alaska 99576 ~ FAX 907.842.5932 ~ Phone 907.842.5257 |
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Are
your trees at risk for Spruce Bark Beetles? |
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Pictured
above: Larval stage (first season) |
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Example
picture of how (NOT) to leave a cut area. Cut spruce trees
should be disposed of properly (remove bark
or cut and split to dry) |
• The past several seasons of warm dry summers may likely have increased the presence of Spruce Bark Beetles in Bristol Bay. Warm, dry summers puts stress on spruce trees and makes them more susceptible to attack from Bark Beetle. • Trees are generally healthier with more moisture and therefore more resistant to attack. Cold and wet springs and summers will actually slow bark beetle progression. • Adult Spruce Bark Beetles are dark brown to black in color with reddish-brown to black wing covers. They are cylindrical shaped about 1/4” long and about an 1/8” wide. Bark Beetles feed on the inner bark of Spruce trees. They destroy its ability to move its moisture thru the tree eventually killing it. • Spruce Beetles generally attack mature, older, injured or fallen Spruce Trees. If you find obvious signs of Spruce Beetle in your area, the USDA Forest Health recommends: cutting, splitting and cross stacking them in the sun to dry or de-barking the tree and destroying the tree base where beetles hibernate. • Signs of Bark Beetle include small holes or mounds of brownish saw dust on the tree and tree base. Pull back some bark near bore holes from a (fallen) tree to expose the inner layer for evidence of tunneling. • When cutting down infested trees, cut as low as possible to the ground to remove potential breeding sites. • Spruce Beetles over-winter just below the duff layer at the base of the tree. They begin to move from there in spring depending on temperature. When they are still in the base of the tree, removing the bark will destroy them. Pulling the stump for disposal or burning would also be effective. • Bark Beetles cannot feed on dried or de-barked spruce trees. Removing the bark or drying the wood will destroy the eggs laid underneath. • TO AVOID INFESTATIONS: Don’t leave spruce logs in piles. Split them to properly dry. • Bark Beetles generally live 1 to 2 seasons and females may lay 10 to 150 eggs. Spruce Bark Beetles only feed on spruce tree species with activity happening from mid spring to late fall (depending on temperature). • Bark Beetles can feed on downed spruce trees for 2 years before the moisture content becomes too low. Therefore it's important to split and dry the downed spruce and debark/destroy the tree base. • Bark Beetles generally don’t feed on young trees. Remove older, susceptible spruce trees from your area. Young trees with less competition for sunlight and water can grow as much as 50% faster and are more resistant to attack. • Dense spruce forest stands are more susceptible to bark beetle attack when droughts occur. If you thin your lot and allow more moisture and sunlight to reach remaining trees, they will have a better chance of surviving attacks. You do not have to clear cut. • When cutting spruce trees, cut as low down to the base of the tree as possible. Beetles hibernate in the lowest portion of the tree, just under the duff layer and this portion should also be destroyed. • On level ground, try to keep spruce trees at least 30 feet from your house. Steep slopes require much more distance. • If left untreated in areas they’re developing, the Beetles may destroy many Spruce trees. This quickly creates a serious fire hazard as spruce is a very volatile fuel. • Spruce Beetles are greatly attracted to wind blown or fallen green spruce. They lack the resin and moisture normally used to repel beetle attacks. Large diameter fallen trees can attract up to (5-10 times) the beetles that healthy standing trees would attract! • If
you have a wind blown or fallen spruce in your lot it will
most likely become infested. Methods to deal
with this
are: to cut, split, cross stack and dry the tree during summer
and burn it in the fall/ winter. (During the summer drying process,
beetles will still go to the tree and deposit eggs. But the end
result is that they will be destroyed/burned). It is important
that the dried (infested) wood is burned that fall/winter. If the
wood is allowed to sit and wait for the next summer, adults will
develop and further increase the infestation. De-barking the tree
is also very effective. Another option is burning the bark off
the green tree, which will destroy the eggs. • Spring cleaning is here and so is clearing away old brush and trees. Cut grass, brush and dead trees near your house. • It’s best to prune (Spruce) trees (in the Fall time) to about 8-10 feet high to reduce wildfire risk. Running sap from spring and summer pruning cuts may attract bark beetles. • Burn barrels must always be closely watched, and Open pit fires require a permit! SAVE YOURSELF SOME TIME AND DROP OFF YOUR OLD BRUSH TO THE DUMP !!! • If you have dead or bark beetle infested spruce trees near power lines or power poles, please contact your electric company for safe removal. • If cutting trees on Native Allotments, please contact BBNA Forestry for recording purposes.
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