January 14, 2011

Pine beetle destruction continues
By Laura Van Dusen - Correspondent

Beetle kill evidence The lodgepole pine trees in the foreground have been infested and killed by the mountain pine beetle. The photo was taken in August 2010 on the Summit County side of Boreas Pass. (Photo by Laura Van Dusen/The Flume)

The latest estimated acreages of mountain pine beetle damage in Park County based on aerial surveys released in January show a total of about 230,942 acres of Park County trees have been destroyed by mountain pine beetles since the onslaught began as early as 1994; an estimated 39,814 of those acres were taken in 2010. The result is an approximate 20 percent increase compared with 2009.

Preliminary numbers for the state of Colorado as a whole are showing a total of 3.188 million acres infested with the mountain pine beetle, which reflects an 878,000-acre increase over 2009, an increase in acres of 9.8 percent.

"These are estimated acreages and approximated changes based on aerial surveys," said Sheila Lamb, natural resource specialist with the Pike National Forest. "The numbers are pretty good and represent the best available science, but they are not perfect."

The perimeter of the county border has been affected in all areas (see map, this page). The only areas that have had no mountain pine beetle damage are the treeless areas across South Park.

Areas most affected are in the mountain ranges in the northwest part of the county beginning in the Guanella Pass area north of Grant, going southward on the north side of the summit of Kenosha Pass, the mountains to the north and west of the Jefferson and Como areas, continuing south along the mountain ranges behind Fairplay and Alma, and ending at Buffalo Peaks Wilderness and the part of the Pike National Forest east of the Buffalo Peaks Wilderness. 

 There are scattered small infested areas southwest of Fairplay as far south as the Chaffee County line, some areas south of U.S. 285, including the Indian Mountain and Buffalo subdivisions, and a few areas in the Thirty-Nine Mile Mountain and Dick's Peak areas northwest of Guffey.

The area east of the Buffalo Peaks Wilderness in Pike National Forest has experienced pine beetle activity in ponderosa pine stands.

But Pike National Forest Acting Timber Management Assistant and Forester Chris Kuennen said: "I haven't seen any new beetle-kill (there) for a few years." He went on to say that he has heard reports of small infestations in the Indian Mountain and Buffalo area, where the beetles are attacking bristlecone pines.

The areas of the heaviest new infestations of mountain pine beetles are northwest of Jefferson near Jefferson Lake and Georgia Pass and also in the Buffalo Peaks

Wilderness.

The beetles have an appetite for lodgepole, ponderosa, limber and bristlecone pines. "They don't like spruce," said Kuennen, but they will bore into those trees occasionally. They don't breed in the spruce and normally won't kill a spruce tree, he said.

Ponderosa and bristlecone are usually more resistant to the mountain pine beetle, said Mike Pill, forester with the Colorado State Forest Service based in Woodland Park. He said that the mountain pine beetle is present all across Colorado, but "people have been proactive about managing their land, so the numbers of beetles have been kept in check although the infestation is still considered epidemic."

The recent dry conditions this winter in Park County could contribute to an increase in mountain pine beetle infestations. A healthy tree is more able to fight off and repel insect attacks. Dry conditions can cause trees to be less healthy.

The dark area shows the mountain pine beetle infestation in Park County through 2009. The light areas show the new infestation that occurred in 2010. (Map courtesy of Sheila Lamb, natural resource specialist, South Park Ranger District, Pike National Forest)

"That is why you see an insect cycle follow a dry cycle," said Lamb. She said that a healthy tree that is not in a drought cycle will be able to repel the insects. The pressure of water and sap will push the beetles out.

On the other hand, an unhealthy tree, being further weakened by a drought and possibly with other insect problems, will most likely succumb to the pine beetle onslaught, she said.

Pill said that trees store up energy from the previous season. A lack of moisture in 2011 would not be noticed in a tree until 2012.

How can one know if a tree is infested?

According to the Colorado State Extension Web site at www.ext.colostate.edu, the signs of mountain pine beetle infestations are:

1) Popcorn-shaped masses of brown, pink or white resin, called "pitch tubes," on the trunk where beetle tunneling begins.

2) Boring dust in bark crevices and on the ground immediately adjacent to the tree base.

3) Evidence of woodpecker feeding on the trunk. Patches of bark are removed and bark flakes lie on the ground or snow below tree.

4) Foliage turning yellowish to reddish throughout the entire tree crown. This usually occurs eight to 10 months after a successful mountain pine beetle attack.

5) Presence of live mountain pine beetles (eggs, larvae, pupae and/or adults), as well as tunnels under the bark, and

6) Blue-stained sapwood.

How to stop the mountain pine beetle

Chemical sprays have been effective in preventing infestation of single, high-value trees, but it is not cost-effective for a large number of trees.

Once a tree has the signs of infestation, there is nothing that can be done to save that tree. Kuennen suggests cutting the tree down as soon as possible and cutting the trunk in sections to expose as much of the inside of the tree as possible to sunlight and wind so the tree will dry out quickly. When the tree has dried out, the food supply for the beetles is gone and they will die. This is best done in the winter before the beetles wake up from hibernation and fly to another tree.

Removing the bark after cutting down the tree will help kill the beetles, as well as chipping or burning the wood, according to a press release by the Colorado State Forest Service.

Cold weather will kill the mountain pine beetles, but it has to be extremely cold for a long period of time. The Colorado State Forest Service said that at lease five successive days of minus-30 degrees Fahrenheit are necessary to kill the mountain pine beetle.

Pill said that if a tree is suspected to be infested with the mountain pine beetle, a call to the Colorado State Forest Service or a local tree nursery can confirm the diagnosis. The mountain pine beetle can be confused with other insects. A Colorado state forester can help identify the insect and advise a course of treatment or disposal of the infected tree so that other trees in the area will not become infested. The forester can also answer questions on prevention of mountain pine beetle infestation to healthy trees.

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