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Cold weather, control work 'crushing' Alberta mountain pine beetle

“It’s been a real concerted effort on the part of forestry and other ministries to battle with the pine beetle but getting help from Mother Nature with a few good cold snaps has helped, too.”

Efforts to squash once devastating populations of mountain pine beetle to endemic levels in Alberta are proving successful.

That, and Mother Nature is doing her job, as she always has.

“It’s been a real concerted effort on the part of forestry and other ministries to battle with the pine beetle but getting help from Mother Nature with a few good cold snaps has helped, too,” said Ken Fry, an entomologist and horticulture instructor at Olds College.

A news release by the province in mid-December announced mountain pine beetle populations have declined 98 per cent since the insect’s peak in 2019.

“To mitigate wildfire risk and negative impacts to the forest industry, watersheds and endangered species, the province has been actively managing mountain pine beetle for more than 15 years,” states the release. “Alberta will continue to invest in the mountain pine beetle control program to ensure its continued success.”

The Ministry of Forestry and Parks was contacted for an interview with a subject matter expert, but the request could not be met in time for publication.

The province’s management tactics for beetle populations are a mixed bag of baiting beetles with pheromones, harvesting and removing infested trees and burning. To find and measure the distribution of beetles, it surveys for signs of infested trees on the ground and in the air.

Using this information and measuring cumulative effects of mortality factors and beetle overwintering survival informs ongoing efforts to manage the insect’s population in Alberta.

Beetle distribution maps based on red tree sites – which are markers of an infected, dead or dying tree – show populations have dropped dramatically in the provincial forest areas of Edson, Whitecourt and Rocky Mountain House since 2019.

In the Calgary Forest Area, however, map data indicates populations have stayed largely the same in the Bow Valley area and have extended more south into Kananaskis Country.

An adaptation in pine beetles that produces anti-freeze-like compounds keeps the insect from freezing in winter unless temperatures drop to around -40 Celsius for several consecutive days, which can result in mass kills.

Fry said the last few winters, beginning in 2019, have been formidable foes to the beetle, but the impact also varies by how quickly the cold comes on and the time of year – it will be more effective if early or late in winter when beetles are not as acclimatized to the cold weather.

“Overall, in terms of the distribution of beetles, the cold is probably still the biggest factor, in knocking those populations back,” said Fry.

“We’re accustomed to having cold winters throughout the province, but the last few years it’s been somewhat atypical in the sense that it got down to minus 35-40 (Celsius). That’s not uncommon, but to have it do that in three of four successive years, and for those cold snaps to be four or five or more days, that’s going to cause a certain amount of mortality or death to the beetles.”

Nadir Erbilgin, a professor and chair of the renewable resources department at the University of Alberta, said measured beetle populations haven’t shown any sign of recovery since 2019.

“I don’t know what it means with the temperatures that we saw [last] week, but I will say the cold has a huge impact on crushing the beetle populations,” he said.

The mountain pine beetle rapidly kills pine trees by clogging and destroying a tree’s conductive tissues with a blue-stain fungus. The insect’s larvae feed on the tree and the combined effects of the fungus and larval feeding can lead to the tree’s death within a month of infestation.

“The more economic aspect is it really kills the trees and that affects tree stands for harvesting and weakens the tree, promoting wildfires in the province,” said Erbilgin.

In its news release, the province noted there are 5.5 million hectares of pine in Alberta susceptible to mountain pine beetle with a value of more than $11 billion.

“Then there’s wildlife, like bears, caribou and other environmental aspects that tie into the biological damage it can cause for habitat,” Erbilgin added.

Left unchecked, beetle outbreaks can devastate pine forests, which is what the province saw in 2006. A long-distance dispersal of beetles from outbreak areas in B.C. reached western Alberta and new infestations rose rapidly.

The province’s mountain pine beetle management plan was introduced shortly after in 2007.

At risk to the insect are extensive areas of lodgepole pine ecosystems in the lower and upper foothills sub-regions that include Alberta’s major watersheds, noted the management plan. This includes Kananaskis Country, Canmore, parts of the MD of Bighorn, Îyârhe Nakoda First Nation and Banff National Park, which has its own mountain pine beetle management program.

The province’s mountain pine beetle survey and control program is active for the 2023-24 season and could run until March 31, 2024, in some areas. Identified burn zones in the Bow Valley include around Harvie Heights, the Canmore Nordic Centre, Three Sisters, Cougar Creek, Dead Man’s Flats and Skogan Pass.

The province also recently completed burning in the Chiniki Lake area from Jan. 9-12.

The province’s long-term strategy is focused more on the reduction of mountain pine beetle habitat by targeting and harvesting the amount and distribution of mature pine across the landscape, which beetles can more easily attack.

Parks Canada’s plan is similar, involving prescribing fire to infested trees and areas of concern.

Jasper, Yoho, Kootenay and Banff national parks, in addition to other mountain national parks, have seen mountain pine beetle populations declining since 2019.

“There’s no active mountain pine beetle populations in any other park right now [except Banff],” said Jakub Olesinski, forest health specialist with Parks Canada.

“There are a few pockets still in Jasper, but basically there’s nothing in other parks right now that’s active.”

Olesinski said areas affected in Banff include around Castle Mountain, near the Banff townsite and near the east gate of the national park.

“Those are really the three major areas where we still see some activity. But again, this is on a strong declining trend.”

However, conditions for prescribed burns have been challenging in the last couple of years, he said. Last year was Alberta’s worst wildfire season on record and Parks Canada did no burning for mountain pine beetles in Banff National Park.

“There’s definitely a lot of caution with planning of activities like prescribed burning that needs to be taken,” said Olesinksi. “Conditions in following years may be detrimental to whether we are able to do any prescribed burning or not. This has to be carefully planned.”

Controlling the population is important to prevent outbreaks or near-outbreak levels, said Erbilgin, but complete eradication of the species which is native to forests in western Canada isn’t the goal. In fact, it would be detrimental to forest health.

“We don’t want to get rid of the entire population. The beetles are very important ecologically, they selectively kill trees that provide habitat for wildlife or other organisms,” he said.

“They’re important to this part of the ecosystem. Same as fire. I know we’re starting to see more and more fires, but we also have to accept that these are parts of our ecosystem.”

The Local Journalism Initiative is funded by the Government of Canada. The position covers Îyârhe (Stoney) Nakoda First Nation and Kananaskis Country.

About the Author: Jessica Lee, Local Journalism Initiative Reporter

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