Mountain Wood Pests Part I – The Mountain Pine Beetle
The mountain pine beetle has infested much of British Columbia’s lodge-pole pine, and it is killing millions of trees. And while normally, environmental conditions naturally inhibit the spread of Dendroctonus ponderosae, warming trends over the past 15 years have not provided the temperature shifts that would naturally control its population.
The mountain pine beetle has already left an historic legacy in the BC forest and it is making its way into areas of the United States as well.
It’s an alarming legacy:
- March 2008. Pacific Bioen-ergy’s pellet plant, Prince George, BC: A spark ignites sawdust and it explodes.
- August 2009. Pinnacle Pellet, Williams Lake, BC: air, sawdust and spark = explosion.
- December 2010. Pacific Bioen-ergy’s pellet plant, Prince George, BC: Another explosion. Spark and sawdust combust.
- April 2011. Pinnacle Pellet, Armstrong, BC: An explosion causes a fire that quickly spreads into the plant’s basement and attic.
- January 2012. Babine Forest Products, Burns Lake, BC: An explosion at the mill kills two workers. A BC Safety Authority report indicates that the blast was fed by unusually-dry sawdust.
- April 24,2012: Lakeland Mills, Prince George, BC: An explosion kills four workers and injures 23 more at the plant [i].
What the Pine Beetle Does to a Tree
Mountain pine beetles develop in several pine species, especially ponderosa, lodge-pole, Scotch and limber pine (bristlecone and pinyon pine can be attacked). A pine beetle targets trees distressed by injury, poor site conditions, fire damage, overcrowding, root disease or old age. As the mountain pine beetle populates an area, it can attack most large trees in numbers [ii]. This has occurred in monumental proportions in British Columbia.
Mountain pine beetles live and feed under the bark. Generally, females seek out large-diameter, living, green trees and tunnel under its bark. Each beetle pair forms a vertical tunnel in which to mate and produce approximately 75 eggs. Once hatched, larvae tunnel away from the egg gallery and feed off the nutrients and moisture of the tree (thus cutting off its food supply)[iii].
Mountain pine beetle larvae survive winter under the tree bark by metabolizing glycerol, an alcohol which serves as antifreeze. The larvae continue feeding until they emerge in spring, when they mature into pupae. By summer, the pine beetle life cycle begins anew with an expanded family. They leave dead pine behind: reddish-yellow carcasses with blue-gray sapwood [iv].
The Lumber Production Challenge
As of April 2011, the Government of British Columbia estimates that the mountain pine beetle has consumed 17.5 million hectares (43.2 million acres) of provincial forest [v].
“It’s basically the challenge of responding to the mountain pine beetle,” said John Allen, President of the Council of Forest Industries, which represents more than 50 BC sawmills [vi]. Allen explains that beetle-infested lumber is much drier and more brittle to process. While it still represents useable lumber to environmentally-minded producers, the risks need to be accurately assessed as well.
If pinewood remains of such vast quantities represent a milling opportunity, lumber professionals are most challenged to adjust their processing to accommodate for the barren moisture content of dead pine. Stay tuned for more on that in Part Two: Modern Wood Pest.
[i] Hoekstra, Gordon “Wood Dust Linked to at Least Five Explosions in B.C. Mills.” Vancouver Sun. Vancouver, BC: April 28, 2012.
[ii] Leatherman, D.A., I. Aguayo, and T.M. Mehall “Mountain Pine Beetle: Fact Sheet.” Colorado State University (Extension).
[v]“Beetle Facts.” Ministry of Forests, Lands and Natural Resource Operations: Government of British Columbia.
[vi] Burgmann, Tamsyn “Industry Fingering Pine Beetle for Some Blame in Fatal Mill Explosions.” Winnipeg Free Press. Winnipeg, MB: April 25, 2012.