Cold temperatures last winter and extreme temperature fluctuations this spring combined to cause significant mortality to mountain pine beetles infesting trees in Alberta. Mortality surveys completed by the Government of Alberta show beetles had low survival throughout areas of the province where trees are infested, with the exception of some hot spots in northwest Alberta.
"At the same time, the cold weather did not completely eliminate the beetles and there is still the threat of additional in-flights from British Columbia," says Alberta Sustainable Resource Development Minister Mel Knight.
As well, the Minister explained, the trees the beetles infested before dying are also dead and work must be done to allow regeneration of new forests to replace those lost to attacks.
As a result, the Alberta government is continuing its action plan to minimize the spread of infestations by a variety of methods, including single-tree removals, stand-level harvest, and controlled fires.
Considering the 2010 over-winter mortality surveys and the risk of in-flight from B.C. this summer, the government has determined the following areas are a high priority for beetle control: Whitecourt/Slave Lake, Grande Prairie, Banff/Canmore/ Kananaskis, Oldman River/Crowsnest Pass.
The Alberta government's objectives are to minimize the spread of beetles north and south along the Eastern Slopes and to prevent beetles from spreading east in the boreal forest.
In related news, a study underway at the University of Alberta is looking at the effect of tree loss caused by beetles on water levels and new forest growth, the Edmonton Journal reported in June.
The study authors, Uldis Silins and Ellen Macdonald of the Department of Sustainable Resources, note that pine trees use up massive quantities of precipitation. "Once these forests die, that water has to go somewhere," said Silins. "It's basically going to go into the ground, and you're going to see increased run-off." That run-off could leech nutrients from the soil into groundwater, potentially lowering water quality downstream. That could also result in algal blooms, which can choke lakes and kill off fish.
The three-year study is currently at its halfway point.