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Mortality rates of the mountain pine beetle (MPB) remain similarly low this year to last year, but that doesn’t mean Hinton can say goodbye to the pest yet.
The beetle has killed a significant amount of pine trees in the Hinton area, but annual mortality rates are predicted to decline for the immediate future as a result of two consecutive years of generally low MPB survival.
In the Edson Forest Area, which includes the Hinton area, populations have been decreasing since 2016.
Very cold winter ambient temperatures of -37°C and below can cause significant levels of MPB mortality, according to a release from Albert Agriculture and Forestry (AAF).
Of the 69 sites sampled provincially this winter, 47 showed low MPB over-winter success, 20 showed moderate success, two showed high success, and zero sites showed extremely high MPB over-winter success.
These sites are sampled in the spring once mortality-causing weather events are past.
Many beetles survive under the snowpack, noted AAF’s release.
While there was a low survival rate following this winter, the larvae that did survive appeared to be well on their way to exiting the trees and finding new trees to attack, said Andrea Sharpe, AAF Forest Health Officer.
Last year, 26,307 trees were controlled within the Edson Forest Area during the 2019-2020 MPB Year.
“We still have a significant MPB program here as populations continue to impact this area,” Sharpe said.
MPB spring population forecast surveys or r-values are conducted throughout the province between May 15 and June 11 each year.
R-values measure the proportion of live larvae and adults that survived the winter compared to the number of attacks from the previous calendar year.
This year 16 sites were conducted in the Edson Forest Area and showed generally low success, similar to 2019.
The results of combined surveys including the r-value surveys, aerial surveys, and ground assessments, will help prioritize areas for single tree treatment and timber harvest control operations this winter.
The population forecast survey does not account for population changes caused by long-range immigration of MPB from heavily-infested areas, AAF’s release stated.
The risks of beetles migrating into west central Alberta from Jasper National Park has subsided with low reproductive rates, high overwinter mortality rates, and host depletion in the park, Sharpe added.
“This could mean that Hinton will see a decrease in newly attacked trees in the coming years,” added Caroline Charbonneau, area information coordinator of AAF’s Edson Forest Area
The leading edge for MPB infestation priorities will not be determined until the fall when aerial surveys are conducted, although the Edson Forest Area remains a priority for continued management due to the large volume of connected pine.
The way trees killed by MPB burn is not the same as a normal pine stand, explained Charbonneau.
“We’re looking at different types of fuel that would be similar to a dead MPB stand so that we can anticipate its fire behaviour. By adopting a new way of assessing these stands, we can better prepare our initial attack crews when fighting wildfires,” Charbonneau said.
Two colder-than-average winters, low reproduction rates, and aggressive control activities around Hinton helped slow and stabilize population growth.
Both industry and Alberta Agriculture and Forestry (AAF) have been working on several plans that involve harvesting and single-tree removal.
AAF has been conducting a lot of FireSmart work around the Hinton area as well.
A large percentage of the work is the maintenance of existing FireSmart treatments, stated Charbonneau.
“We are always looking for new FireSmart opportunities and work closely with industry and other partners,” she said.
Residents can also do their part in protecting their homes, property and community. Visit firesmartcanada.ca for more information.