Pine beetle threat looms over county

A pine-beetle infestation rusting forests west of the Continental Divide may be poised to kill thousands of trees on the mountains of Boulder County. It wouldn't be the first time.

A Camera headline published Aug. 8, 1971, reads: "Bark Beetles Lay Siege to Ponderosa Pines: 1,000 Casualties Counted Near Gold Hill." Seven years later, an Aug. 14, 1978, story reported: "Colorado and other mountain states are in the midst of a pine beetle epidemic that threatens several industries with financial disaster but will take years to clear up, the U.S. Forest Service says."

Whether Boulder County 's pines again will fall at the jaws of so many quarter-inch insects remains unclear. In the late 1970s, roughly 2 million Front Range ponderosa pines died, with mature pines in the foothills above Boulder hit particularly hard.

The Western Slope outbreak is killing lodgepole pines , which are common only above about 8,500 feet elevation in Boulder County. Ingrid Aguayo, forest entomologist for the Colorado State Forest Service, said aerial surveys had spotted a pine - beetle infestation among ponderosa pines in Woodland Park near Colorado Springs. But, she said, "for now it's still focused on the Western Slope and lodgepole is the big concern."

But conditions could be ripe for a wider Front Range outbreak, scientists say, and pine beetles are already making their mark on the county 's western mountain tops.

Pine beetles burrow beneath bark to lay eggs. Larvae fan out, feasting as they mature. The following summer, they take flight from trees rendered a dead orange to seek new victims.

Yan Linhart, a University of Colorado biology professor, said infestations often kill 60 percent to 70 percent of a forest's trees, but 90 percent of trees can die in extreme cases. That's happening in places like Granby.

He said the Western Slope beetles' preference for lodgepole pine could keep a die-off limited to local lodgepole pine at higher elevations. But drought and unnaturally high forest density from decades of fire suppression has weakened trees as they compete with each other, he said. Less water per tree means less sap production and trees succumbing to fewer beetles.

"If we have a very dry year where trees are stressed through the winter, it could get very nasty very quickly," he said.

Still, a rapid large-scale attack on the Front Range will probably depend on beetles switching to ponderosa pines , he said.

Pine beetles are already here in limited numbers, said Bob Bundy, a forester with the Colorado State Forest Service in Longmont.

"They've started to jump over the Continental Divide from Granby and that area," he said.

The insects are hitting lodgepole pines in small pockets on Tennessee Mountain southwest of Nederland, he said, and the Forest Service is hearing from residents about pine - beetle attacks near Allenspark.

Greg Ching, who lives among ponderosa pines on Magnolia Road, said his trees are still green. But he and neighbors are considering the risk of pine beetles more than in recent years. Among other things, he said, the community has avoided chipping forest slash during the summer to avoid attracting the bugs.

But in the end, Ching said he understands that beetles are part of life in the forest.

"It's nature's way of handling tree diversity," he said.