The mountain pine beetle population continues to flourish in Jasper National Park, according to new data from the province that indicates the local population survived the winter relatively unscathed.
“Overall the sites that we sampled in Jasper survived very well relative to the rest of the province,” said Erica Samis, manager of forest health and adaptation with Alberta Agriculture and Forestry.
“What that means is the beetles were able to reproduce successfully and that the winter did not cause a lot of mortality,” she said, explaining it indicates an expanding or increasing population.
The new data was collected as part of an over-winter mortality survey conducted by Parks Canada and Alberta Agriculture and Forestry this spring.
The news isn’t good for pine trees, which have been ravaged by the beetles as they spread eastward from British Columbia to Alberta.
In recent years, the number of infested pine trees in the park has surged from about 400 trees in 2012 to more than 6,000 hectares, according to the most recent survey by Forestry Canada.
Parks and the Canadian Forest Service are currently conducting aerial surveys to map out the number of trees that were attacked by the mountain pine beetle last year, explained Samis. They are looking for trees that are red or fading in colour, which indicates they are dead and were infested by the beetle. The survey is expected to be done by Sept. 15.
Once completed, the will also conduct population assessments on the ground to confirm their findings and count the number of newly infested trees that are in the vicinity of the dead trees.
Dave Smith, fire and vegetation manager for Jasper National Park, confirmed Parks is currently conducting its annual mountain pine beetle survey and said once finalized the data will be analyzed and a report will be released later this year.
“The hope is between the two agencies that we will be able to do some longer term population monitoring so that we can really get an idea of what the population in Jasper is going to do,” said Samis.
“We really can’t speak to any kind of trend or population changes until we have a couple of years of consecutive data.”
She acknowledged infestations in the park have been monitored in the past, but said this is the first year the provincial government and Parks have worked together in a concerted effort to establish a monitoring program using the same procedures.
It's not clear why the beetle population in Jasper survived the winter better than in other parts of the province.
“The Jasper area and the Grande Prairie area were actually a couple of our more successful populations,” said Samis, explaining it’s too early to know why that might be.
“There are a variety of factors that kind of lead into beetle population success in terms of everything from stress on the pine trees, to annual weather, to climate, to the number of beetles that are in the area.”
According to experts, the temperature when beetles start to die is not fixed, but varies given the larvae’s response to daily temperature fluctuations.
For example, an under-bark temperature of –37°C will kill 50 per cent of a mountain pine beetle population, however, if the temperature drops to –20°C in the fall, before the beetles are prepared for winter or when beetles are starting to become more active in the spring, this will also kill them.
Samis said the best way to stop the spread of the beetles is through cutting down and burning or chipping infested trees before they have a chance to hatch and spread to healthy trees.
Another effective way is removing susceptible trees through prescribed burns or harvesting them before they are infested, she said.
“Once the tree is red and dead, the beetles have already left that tree so there is no sense in taking those down from a beetle control perspective,” said Samis.
Currently the beetle population has spread east of Slave Lake or about 150 kms from the Saskatchewan border.
Paul Clarke
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