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Surveys show lower MPB survival

Masha Scheele

Population forecasts suggest that local mountain pine beetle (MPB) did not produce large numbers of new beetles in the area this year, reported Alberta Agriculture and Forestry (AAF).

Data for the MPB survival in the Hinton and Edson region was collected and sampled over the past few months by AAF and West Fraser – Hinton Wood Products.

The decline in new beetles will help slow the spread, which is great news for Alberta, stated Caroline Charbonneau, AAF area information coordinator.

“However, it is common for these pests to take a large hit in population but come back strong in numbers in areas where they do really well or have not been impacted as hard,” said Charbonneau.

“Alberta cannot be complacent. This event offers an opportunity to further suppress the populations; we will ‘kick them when they are down’. This means that we will continue our aggressive survey and control programs, working in conjunction with forest industry and local municipalities.”

The continued risk of beetles migrating into west central Alberta from Jasper National Park makes the Edson forest area a high priority region for control this winter because of the large volume of connected pine and the potential for the infestation to spread.

The purpose of spring population forecast surveys, called r-values, is to measure the proportion of live larvae and adults that survived the winter compared to the number of attacks from the previous calendar year.

Spring population forecast surveys took place between May 13 and June 10, 2019 and surveys were conducted at 64 sites or 385 trees within Alberta’s forested area, compared to 58 sites or 302 trees in 2018.

In the Edson Forest Area, 29 sites or 265 trees were sampled this year, and in order to collect more samples in a short time period, the surveys were conducted by both AAF and West Fraser. According to AAF, the spring population forecast surveys showed that overall, MPB success was significantly lower this winter compared to previous winters. 

Most notable is the decrease in over-winter success in the core infestation adjacent to Jasper National Park, where a 98 per cent mortality was reported earlier this spring by David Argument, Jasper National Park’s resource conservation manager. 

Charbonneau said the data collected in the Edson Forest Area only predicts whether the population is likely to decrease, increase or remain stable. She added that said higher spring mortality was due to a combination of factors, including lower than normal reproduction, which occurred later in the summer, said Charbonneau.

“This could possibly have been attributed to very hot summer temperatures or significant smoke over the province during the time the beetle was flying to their new host tree. Delayed reproduction would have caused the larvae to overwinter in their younger, more susceptible life stage,” stated Charbonneau.

The past winter’s cold temperatures also contributed to the MPB decline as they were left more vulnerable. 

Sample sites are chosen by the forest health officer based on the level of infestation to ensure they are representative of the entire forest area. Four samples are drilled from each tree within the site using a gas powered saw and a four-inch hole saw drill bit. 

The sample, also known as a tree cookie, is an inch in thickness and is carefully pulled from the tree using a chisel to ensure no beetles or larvae fall out of the sample. The number of either live or dead adults, larvae, pupae, young adults and entrance holes are counted in the cookies and entered in a provincial database to be analyzed.

MPB cookies

Trees attacked last summer will be turning red by the end of July, and AAF expects to see many dead red trees along the Rockies north and south of Hinton.

The full extent of the impact will not be fully understood until further population assessment surveys are completed in the fall, added Charbonneau.

West Yellowhead MLA Martin Long stood in the Legislature on June 24 to encourage his recently-elected UCP government to honour its platform of increasing provincial MPB funding from $25 million to $30 million annually, and also to lobby the federal government to contribute similar resources to what its committed to tacking the spruce budworm issue on the east coast.

“Our forest industry contributes $6 billion to our economy every year,” he said.