Scientists are now saying last winter’s cold temperatures in Alberta were cold enough to knock back the population of mountain pine beetles.

Bark samples from 1,266 pine trees at 229 sites show that except for a few hot spots in the north and west, the beetle numbers were pushed back to 2007 levels.

Alberta has spent more than $200 million trying to control the influx of mountain pine beetles from British Columbia. They have conducted controlled burns and have removed trees.

The beetle larvae is able to survive -35°C for several days, but it seems Alberta’s cold snaps happened at precisely the right times to knock back some populations – especially around Whitecourt, Slave Lake, Banff, Canmore, Kananaskis, Oldman River, Crowsnest Pass, Rocky Mountain House and Willmore Wilderness and Grande Cache.

Read more about Alberta’s battle against the mountain pine beetle:
Alberta winter puts dent in mountain pine beetle numbers (Edmonton Journal)