Pine beetle overwintered well in northern Alberta

July 8, 2011, Edmonton – Mountain pine
beetle populations experienced varying degrees of over-winter survival in
Alberta in 2010–2011, ranging from moderate or high survival in the northwest
and central parts of the province to declining populations along the eastern
edge of the infestation and in the southwest.

“There are some small pockets of good news on the mountain pine beetle front
lines this year; but overall, the infestations remain a challenge to Alberta,
and we must continue our aggressive action to protect forest health in the
province,” says Sustainable Resource Development Minister Mel Knight.

Milder winter weather throughout most of
the province’s forests this year is the likeliest cause of greater beetle
survival this year compared to the extreme temperature fluctuations the
previous winter, which led to significant beetle mortality last year.
Over-winter mortality survey results are used to help set priorities for
control work in the coming year. Alberta will continue to target specific areas
for aggressive action against mountain pine beetle in 2011–2012.

Northwestern Alberta

There was high beetle population survival
across the region, indicating an increasing population. Half of the sites
surveyed showed high to extremely high beetle success, with most other sites
showing moderate success. There is a continued high risk of in-flights of
beetles into the region from adjacent infested areas in British Columbia, and
portions of the region are a high priority for control work this year.

Central Alberta

Moderate beetle success throughout the
region this winter indicates a stable population aside from the eastern edge of
the infestation, where populations continue to decline. The area includes
pockets of both high and low beetle success and is at moderate risk of
in-flights from British Columbia this summer. The region remains a high
priority for control work this year because it contains a large volume of pine
and there is good potential for infestations to spread.

Southwestern Alberta

Beetle survival was low in southwestern
Alberta. Local populations declined following both control work and high winter
mortality in 2010, and dropped again in 2011. There are few beetle-attacked
trees in the region compared to previous years, but the area remains at risk of
in-flights from British Columbia populations and is a high priority for beetle
control work in the coming year.

Six million hectares of pine forest in
Alberta are susceptible to attacks by mountain pine beetle. Infestations began
in west-central Alberta in 2006, following a wind-assisted in-flight of insects
from British Columbia, and in southwest Alberta in 2002. Alberta’s beetle
control program was effective in reducing the number of beetle-attacked trees
in the region until a second large in-flight in 2009. Current control efforts
are aimed at local resident beetle populations. Prime objectives of the beetle
management program are to prevent infestations spreading north and south along
the eastern slopes, and further eastward in the boreal forest.