Cold enough (maybe) to kill a pine beetle
EAGLE COUNTY ” The metallic undergarments of witches ” and the contents therein ” may be one measure to compare this week’s extra-cold temperatures.
But was it cold enough to kill the dreaded pine beetles turning the state’s forests red?
Not quite, said U.S. Forest Service entomologist Bob Cain. According to studies, he said the temperature has to be at 25 or 30 below zero to kill the beetles and their larva under the bark.
Still, with temperatures in some areas dipping into the negative 20s and even 30s, it was bound to make the critters uncomfortable, he said.
“I think when you get into those negative 30s and 40s, that’s probably going to kill some beetles” Cain said. It needs to be colder than the 25 below shown to kill them in studies, he said, because they stay warmer under the bark of trees.
It’s not really clear, Cain said, what kind of sustained cold will really make a dent in the pine beetle epidemic.
“It’s great to see these kinds of temperatures, and I think we will see some mortality ” the question is how much,” he said.
The susceptibility of beetles to cold, Cain said, varies throughout the year. With this cold snap a little on the early side, he said it might have more of an effect on them. On the other hand, the deep snowpack also serves to insulate the trees, keeping the beetles warmer.
“It’s a question mark,” he added, saying that samples taken of infected trees next spring may give some answers.
This week’s temperatures are literally arctic, according to Dave Nadler, a meteorologist at the National Weather Service in Grand Junction.
“It’s a big air mass that dropped down from the arctic area, and the combination of high pressure, clear skies and snowpack just set the stage for some very cold temperatures,” Nadler said. “But we should be seeing a moderating trend in temperatures.”
All the recent snow, he said, contributes to the cold since any warming sunlight is radiated back into space rather than being absorbed by the ground.
Overnight temperatures will likely dip below zero over the next few nights ” with daytime highs in the teens and 20s ” with a return to near-normal by the beginning of next week.
On Vail Mountain Thursday, crowds were thin and on-mountain staff were doing what they could to stay warm.
“It’s pretty cold,” said Alli Gorham, a ticket checker at the Riva Bahn lift who called herself a “gatekeeper to paradise.”
Gorham said she was countering the cold by wearing five shirts underneath her coat and doing exercises.
“I like to do lunges to stay warm,” she said. “I’m going to have the best legs in town.”
Lift operator Jon Heintz, who was on the mountain at 6:30 Thursday morning, said it was tolerable by 10 a.m.
“At first it was excessively cold, like you couldn’t even be out here,” he said of the -15 degree morning. “You couldn’t have any skin showing because of frostbite.”
Heintz said the lift workers were alternating in 15-minute shifts to stay warm. But things were looking up by mid-afternoon, when temperatures climbed into the mid 20s.
Alex Miller can be reached at 949-0555, ext. 14625, or email@example.com.
Vail Daily, Vail, Colorado