Why extreme cold is good for Alberta forests
Aerial view of forest affected by mountain pine beetle.
Published Friday, February 8, 2019 3:27PM MST
Not everyone is unhappy with the extreme cold gripping the province.
“There are some of us that are cheering,” said Janice Cooke, a professor at the University of Alberta.
When the temperature drops low enough, as it has this past week, it can be deadly for the mountain pine beetle.
“We’re actually talking about the larvae from these beetles. The beetles are flying in the summer; they mate, they lay eggs, those eggs hatch and then the larvae are growing all through the fall, so it’s the larvae that are sitting under the bark over wintering and getting ready to grow again in the spring, so that’s what we’re hoping that the cold will kill,” said Cooke.
She said the larvae contain compounds that act as anti-freeze to help them survive the winter, but that compound becomes less effective as the temperature dips.
“It’s not an on/off switch that they’re all alive or they’re all dead; what we see is that the colder it gets, the more of these larvae that succumb to the cold,” Cooke said.
The mountain pine beetle has infested trees in B.C. and Alberta, including Jasper National Park and forests east of Hinton.
“Red trees are dead trees,” said Cooke. “All around those trees are trees that have been attacked by the beetles that came from those dead trees,” she added.
Cooke said the best part of this cold weather is that it has hit areas where the outbreak is most severe.
“There are people who are better at math than I am, they run complex models and those models tell us that we’ve had significant mortality as a result of this cold event. So those beetles are dying in the trees and we’re having more mortality now than we’ve had in the past few years, so that’s the good news.”