Sunpine Forest Products Inc. is taking a cautious approach to recent scientific data predicting up to 95 per cent of pine beetles were killed off by deep freezes this winter.
Computer models run by the Canadian Forest Service forecast 95 per cent pine beetle mortality in Southern Alberta and 90 per cent on the Eastern Slopes in Northern Alberta.
“It predicts pretty high mortality and I sure hope the prediction is on,” said Tom Daniels, community forester with Sunpine, a division of West Fraser Mills Ltd.
But how much impact the cold actually had won’t be known until forest experts can get into the woods themselves to check trees later this spring, he said.
Generally, a two- to five-day cold snap of at least -40C is required to kill the beetles. Cold spells in fall or spring are particularly effective because they catch the beetles at a time when their natural anti-freeze is at lower levels.
However, pine beetle populations are hardy and it is estimated a 97.5 mortality rate is needed to stop the growth of the population.
“The reason for that is just the dynamics of the population,” said Daniels. Females lay about 100 eggs, which hatch and can soon lay 100 of their own. “That population can pretty much explode in a matter of a couple of years.”
Even if the province hit the magic 97.5 per cent mark, that doesn’t mean the pine beetle problem is solved.
“Even if we killed every beetle, we’re not out of the woods. We’re not even close to being out of the woods,” he said. Until the B.C. pine beetle population crashes, which is not predicted to happen until 2013, Alberta’s forests will continue to be threatened.
Currently, Alberta Sustainable Resource Development maps show pine beetles have invaded Southern Alberta, and used mountain passes to infest blocks of forest along the border with B.C. southwest of Grande Prairie.
The West County has not seen serious infestations yet, but there are troubling signs. Sundre Forest Products workers have baited certain trees in its forest management area with pine beetle pheromones to attract the bugs. The project was started in 2007 and five or six beetles were found in test trees. Last year, up to 55 of the rice-sized critters were spotted.
Daniels said they are not sure what has caused the jump yet, but foresters will be watching closely.
The province has taken an aggressive approach to try to ward off the scale of destruction in B.C., where four out of five mature lodgepole pines are expected to be killed off and 33.4 million acres of pine forest have been infected.
Alberta forestry companies have been asked to harvest 75 per cent of the tree stands most susceptible to pine beetles over the next 20 years. West Fraser has proposed removing 54 per cent, the most its existing processing plants can handle.
Alberta Sustainable Resource Development spokesman Darcy Whiteside was also treating the Canadian Forest Service report with caution.
“It’s really tough to look at the impacts on pine beetle until the early spring,” he said.
That’s when government crews will go out and inspect trees at about 300 sites.
“It’s nice to hear, definitely, (mortality rates) in the 90s. We know that it’s a new model and we just tend to be fairly cautious.”
pcowley@www.reddeeradvocate.com