When temperatures drop in Colorado's mountains, people start asking - is it cold enough to kill those pesky bark beetles that are destroying the trees?
"That's the question of the day," said Ron Cousineau, assistant district forester for the Colorado State Forest Service in Granby.
The answer, so far, is no.
Researchers say for a significant beetle die-off, low temperatures must hit 35 below to 40 degrees below zero for several consecutive days.
And while it has been cold - and is going to get frigid again as an Arctic front is forecast to bring temperatures as low as 30 below to the mountains this weekend - it just isn't cold enough to cause a massive beetle die-off.
Kremmling's lowest temperature reading so far was minus 32 degrees Jan. 16, according to the National Weather Service.
In Denver, which isn't menaced by the beetle, the Friday night temperature is expected to fall to minus 7.
Still, some are hoping the frigid weather will kill the cold-hardy larvae buried beneath the tree bark.
"Two weeks ago, we had two weeks of 20 to 30 below every day," Cousineau said. "The phone was ringing off the hook. People were coming by, people in the grocery store were asking, 'Are the bugs all dead?' Come on, it's not that easy."
Those lows are recorded in the river valleys, where the cold settles into the valley floor. The higher on the mountainsides, the warmer the temperatures. And that is where the trees are, Cousineau said.
Trees also are insulated by snow on the ground, he said.
Aerial surveys of the mountains last year revealed 660,000 new acres affected by the beet les - a 50 percent increase from what was seen in 2005, said Joe Duda, forest management division supervisor for the Colorado State Forest Service.
A cold snap early or late in the season would cause the most mortality, Duda said, but the beetles would rebound.
One reason they're so hardy, Duda said, is that as the beetles hibernate, they build up a form of glycol that makes them less prone to freezing.
Glycol is the same chemical used in automobile antifreeze.Denver Post
