Forests in the crosshairs
Beetles, SAD changing local landscapes
Michelle Burkhart
Originally published 2008-01-17



In three to five years, all mature lodgepole pine forests in Colorado may be wiped out by mountain pine beetle -  and Gunnison County is not likely to avoid the fray.
The U.S. Forest Service (USFS) and Colorado State Forest Service announced the prediction Monday morning when the agencies released their 2007 aerial survey results. The monitoring also tracked sudden aspen decline (SAD), spruce beetle and other defoliating insects.
Mountain pine beetle infested approximately 500,000 new acres of lodgepole trees in 2007, according to the survey where officials flew over forests and used GPS technology to identify trends in forest health. In total, more than 1.5 million acres in Colorado have been impacted by the beetle since the first signs of outbreak in 1996, officials reported.
"This is an unprecedented event and it's unprecedented growth in a single year," said Rocky Mountain Regional USFS Forester Rick Cables.
Colorado forests are old and ready to regenerate and mountain pine beetles are one agent to accomplish that, he said.
The bark beetle infestation, which has expanded due to drought and warm winters, has evolved into a social issue, Cable said. Most of the focus has shifted away from the forest itself to concerns about fires, homes and watersheds.
The majority of the infestation has occurred in northern Colorado, with only a smattering of pine beetle activity as far south as the Gunnison National Forest.
According to the survey, only 105 acres of lodgepole pine have been affected in the Gunnison National Forest; and the Taylor Park area is the epicenter of that activity.
Lodgepole generally doesn't extend further south in Colorado than around Hwy. 50, explained Roy Mask, the lead entomologist with the Gunnison Service Center - a USFS research office just off of Main Street in the Gunnison.
Mask believes mountain pine beetle will eventually hit epidemic levels in the local forest.
"We have no reason to think otherwise," he said.
The lodgepole pine forests in the Gunnison area have all characteristics to make them susceptible to the beetle, he explained. They are mature, with thick bark and grow in dense stands.
Mask's best guess is that the weather has kept the beetles at bay to this point.
"We do historically know that there's been a lot of cold drainage down the Taylor Park down into our valley," he said.
He said the cold weather theory is already being challenged, however.
In the 2007 aerial survey, researchers were surprised to see that the mountain pine beetle had expanded up to around 10,000 feet in elevation in other areas of the state.

SAD quadruples locally
Mask said SAD is the current concern for the Gunnison National Forest. Acres of aspen damage in the forest increased by more than four times in the last year - bringing the total to nearly 22,000 acres, according to the aerial survey.
Out of the seven national forests under the Gunnison Service Center's purview, Gunnison saw the second largest percentage increase in damage. The Rio Grande National Forest suffered the most, with a 684 percent increase in aspen deterioration in the last year.
The Forest Service estimates that more than 95 percent of the aspen damage came from SAD in most areas.
On a statewide basis, there was a 150 percent increase in SAD in the last year. Roughly 13 percent of the aspen in the state have been affected.
SAD greatly differs from the gradual loss of aspen acreage that the West has experienced for decades. Most experts attribute that slow decline to fire suppression and limited aspen management, since aspens thrive on disturbance.
A combination of factors contribute to SAD's rapid mortality. Warm temperatures and drought have been stressing the trees - especially the ones that are old, at low elevations or on south to west aspects, according to researchers at the Gunnison Service Center.
When insects or disease find these stressed stands, they easily take over.
"We definitely think (SAD is) going to continue in the short term," Mask said.
He said he couldn't predict the long-term outlook at this point, but that he believes some of the lower elevation aspen stands - that string out into the sagebrush landscape - are gone "forever."
They weren't in "ideal aspen habitat to begin with," he said.

Keeping careful watch
While spruce beetles have only appeared sporadically in the Gunnison National Forest, Mask believes they are probably "the next thing that is going to impact (the forest) in a large way."
Spruce forests are much more extensive on the Gunnison National Forest than lodgepole pine, he explained.
Moreover, the spruce beetle infestation "just about surrounds" the Gunnison National Forest, Mask said.
He predicted that it will probably only take a trigger, such as a blow-down from a windstorm or an avalanche, to set the infestation off.
"It's something that our crew will definitely be looking at after this winter," Mask said, referring to monitoring trees in avalanche paths after the unusually snowy winter.
Water issues would be "substantial" with a spruce beetle infestation because that's where local snow loads are stored," Mask said.

Treatments in the pipeline
One thing lodgepole pine, spruce and aspen all have in common in Colorado is that they are old, Cables said.
The USFS' goal is to create a diversity of age classes so that "one insect or pathogen can not destroy an entire forest at once," Cables said.
Researchers at the Gunnison Service Center said some efforts are currently underway locally to help manage forest conditions.
Aspen don't tend to regenerate by themselves well, so the USFS is planning an experiment to test ways of stimulating regeneration in the Terror Creek drainage, just north of Paonia where SAD has taken hold, said Jim Worrall, a pathologist with the USFS in Gunnison.
The agency plans to clear-cut patches of aspen because the trees tend to respond well to massive disturbance, but not thinning, he explained.
SAD, mountain pine beetle and spruce beetle could all have hefty impacts on the Gunnison Basin if they take hold, the local experts say, everything from deteriorated wildlife habitat, viewsheds, water quality and water storage to loss of tourism dollars from fewer "leaf peepers" and hunters.

(Michelle Burkhart can be contacted at 970-641-1414 or michelle@gunnisontimes.com)