Trees at risk of beetle epidemic


— Routt County and state Forest Service officials are urging Steamboat Springs residents to protect mature trees with insecticides prior to May or risk losing trees to the spruce bark beetle epidemic.

The swelling spruce beetle population, along with a healthy mountain pine beetle population, are expected kill thousands of trees in Routt County this summer.

So far, spruce beetles have been feeding on a plentiful supply of fallen trees within the Routt National Forest, but officials expect for the beetles to start spreading throughout the county.

"If the beetles reach a tree, it is dead," said C.J. Mucklow, director of the county's Cooperative Extension Office. "It will not do any good to spray a tree after they have left."

Last year, more than 10,000 trees were killed because of the epidemic that has been fueled by the 1997 Routt Divide Blowdown.

During that event, winds exceeding more than 120 mph toppled more than 4 million trees on 13,000 acres within the Routt National Forest.

Spruce beetles seek out the fallen trees to feed on the cambium layer under the bark, while the dying trees' natural defenses diminish.

With the beetle population surging, the pests are now attacking healthy trees. A large population of beetles doesn't need dying trees to live in. Instead, about 2,000 beetles collectively attack one standing tree, exhaust the tree's defenses and eventually kill it.

From that one tree, between 30,000 and 40,000 beetles can be produced.

Officials are suggesting residents protect their trees with preventative insecticides.

"The most susceptible trees are large, mature spruce and pines with the trunk at the base greater than 8 inches in diameter," Mucklow said.

For the insecticide to be effective, the main trunk must be treated until the trunk is less than 4 inches in diameter. The tree's root collar and any branches greater than 4 inches in diameter must also be treated.

To protect trees from turning orange or red, which happens when they die, officials suggest residents hire a licensed applicator to spray trees with insecticide.

Homeowners can treat the trees themselves but may find it difficult to do so correctly because spray equipment is needed to reach high in the tree.

Residents who want to protect their trees from the spruce beetle need to have the trees sprayed by mid-May, said Andy Cadenhead, a U.S. Forest Service employee who leads a beetle-suppression team.

"There is a small window to get this done," he said.

To protect trees from mountain pine beetle, trees should be sprayed by July, he said.

The beetles attack mature trees because their large trunks can hold numerous beetles. Younger trees are also stronger and able to fight off the beetles.

Cadenhead said the Forest Service is mapping out a plan to protect numerous areas from the beetles this summer.

Several campgrounds in Hahn's Peak, Seedhouse, Granite Summit and those on Rabbit Ears and Buffalo passes are expected to be areas where beetle suppression will be in full force.

Suppression efforts will also be geared to protect the Steamboat Ski Area and housing developments.

The beetle epidemic is a natural event. It occurs about every 20 to 30 years. This epidemic, which is just beginning, is larger because of the blow down.

"Spraying trees will probably become an annual event," said Terry Wattles of the state Forest Service. "It may take 10 years before they are done doing their thing."


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