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Identifying Beetle-Killed Trees Key To Stopping Spread


Pitch tubes indicate that a pine tree has been attacked by mountain pine beetles. This year’s annual Tree Symposium to be held on May 7 coincides with the time landowners must identify and remove beetle-killed trees before adult beetles fly from them to attack other trees.

July 1 has long been considered the start of the beetle flight, but recent studies show that it is occurring earlier. Global climate change and localized weather patterns may be factors that affect flight times. The Town of Estes Park Tree Board recommends that landowners identify, cut down, and remove infected trees before June 15.

It’s in your self-interest to cut and remove beetle-killed trees to prevent the spread of beetles. Beetles fly to the nearest susceptible trees, often ones weakened by drought, poor soil conditions, mistletoe, or disease. Your trees and those of your neighbors are the most likely targets, although beetles have been known to fly as far as five miles. State and county laws require beetle-killed trees to be cut and removed or treated. A similar municipal law is under consideration.

The Tree Board recommends that you inspect every pine, not just ponderosas, for pitch tubes, a sure sign of a beetle attack. Pitch tubes are reddish globs of tree resin that protrude from the bark where beetles have entered. They resemble wads of bubblegum. Trees produce sap in an attempt to expel invading beetles.
Trees are sometimes successful in warding off an attack, so the discovery of pitch tubes is only the first step in deciding if a tree should be cut. By May, trees that are hosting beetles and will die from the attack often display a yellowing of needles over the entire tree.

If a pine with pitch tubes is not showing signs of yellowing, it should still be checked for live beetles under the bark. This requires removing a section of bark with a hatchet or chisel near pitch tubes and looking first for tunnels burrowed by beetles and for the blue stain that results from a fungus carried by beetles. Live adult beetles or beetle larvae indicate the tree needs to be removed.

The Tree Board recently hosted a workshop to train a group of local volunteers and town employees in determining whether a tree harbors live beetles. Call the Town of Estes Park Public Works Department at 577-3588 to request an inspection of trees with pitch tubes. Because of the small number of initial volunteers, it is not possible for them to check entire properties. Out-of-town owners should contact a neighbor or a local tree service for help in checking their properties.

If a tree is infected, the best option this late in the beetle life cycle is to cut the tree and dispose of it. Beetles remain in downed trees until they fly. If you use a tree service, they will take care of disposal. The Town of Estes Park is considering the purchase of an air curtain burner to facilitate the disposal of beetle-killed trees for residents of the Estes Valley. Watch the newspaper for further information.

Using the traditional method of covering beetle-killed logs with plastic is only about 70% effective, according to current studies. The only completely effective way to save beetle-killed trees for firewood is to debark infected areas using a drawknife or chain saw attachment. Exposure to the elements kills the beetles.
Preventative spraying to protect valuable trees on a property needs to be completed before the beetles fly, but it should not be done too early, since its effectiveness wears off. Spraying is typically done from late May through the end of June. The Tree Board encourages landowners to use state-licensed sprayers and to arrange for spraying as soon as possible.

Information on all facets of mountain pine beetles will be available at the annual Tree Symposium on May 7 beginning at 8:15 a.m. in the Town Hall Board Room.

© 2014 Estes Park News, Inc

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