Modern Wood Pests Part II – Processing the Pine Beetle Legacy
In a 1963 edition of Great Basin Naturalist, S.L. Wood described the mountain pine beetle as “the most destructive insect of mature pine forests in western North America [i]. Decades later, British Columbia’s lumber industry deals with over 42 million acres worth of dead pine eaten by Dendroctonus ponderosae.
To Mill Or Not
Although dangerous, BC sawmills are attempting to process the remnants of beetle infested wood. Why? Economically, there is too much of it to ignore. Environmentally, BC government officials want to clean up the central interior of the province in order to replant for future generations.
In an unprecedented move, the British Columbia government ordered Worksafe BC (its health and safety agency) to investigate all BC sawmills in the wake of three worker fatalities early in 2012. Pine beetle wood arrives with very low moisture content (MC) levels and its highly combustible sawdust is a factor in the sawmill explosions that prompted the investigation.
Sorting Out of Lumber in the Sawmill
Lumber operators can adjust sawmill moisture/density sorting systems to accommodate for pine beetle-infested wood. Wagner Meters LDS200 Green Sort System reduces business costs through kiln-time optimization, but can also help identify the low MC levels of pine beetle-killed wood for removal from the kiln process where applicable.
Ironically, BC’s exploding sawmill dilemma is a thumbnail portrait of an industry facing change on two fronts. As lumber operators increasingly face the process of damaged wood, mill processing itself must adjust.
“The game has changed,” says Wayne Winkler, biomass engineer of Briquetting Systems. “Now the magic word is dust. It’s not wet sawdust anymore, it’s dust coming from beetle-killed wood. The dust has lost most of its moisture because it has been dead for years. It is very flammable [ii].
Government has ordered mills to clean up latent sawdust. Winkler believes the measure will be insufficient, but he suggests that lumber operators take a comprehensive, system-wide approach to beetle-infested pine wood processing.
“Fortunately, this problem has been recognized for a long time,” says Wayne Winkler, “…and there is technology to deal with it. The equipment is manufactured in Denmark and has been used around the world for many years [iii].
Waste sawdust is sucked up at collection points throughout a processing plant. Then, it is compacted into revenue-producing products, such as fuel pucks and fireplace logs. However, these are plant-wide systems which can cost several million dollars.
Denmark has deployed waste incineration for a century. Initially, the nation engaged the process to reduce landfill. However, Denmark incinerates its waste for energy purposes. Today, companies that incinerate waste from their own areas receive preferential rights to sell the resulting energy [iv].
The Long Foreshadow
Why does this matter to US producers?
Mountain pine beetles can be transported in infected wood. And more alarmingly, a mountain pine beetle can fly.
Researchers at the University of Northern BC (UNBC) explain that new adult beetles emerge from under pine bark and fly when average highs reach 20 degrees (C.; 68 degrees F.) over three days. In BC, peak flight time occurs in the last half of July each year [v]. Convection, a common fair-weather occurrence during that time in BC, “…may carry some beetles above the forest canopy to be passively transported over long distances by the mean wind within the atmospheric boundary layer. [vi] In fact, local pilots anecdotally reported mountain pine beetle sightings at 1500m (4921 feet) above the BC forest [vii].
The future role of the mountain pine beetle in modern forestry is articulated in UNBC’s research conclusion:
“…the results of the aerial capture and radar analysis…both support the theory that mountain pine beetles can undergo long-range transport aided by wind within the planetary boundary layer [viii].
With the extent of infestation and the amount of pine-beetle affected pinewood lumber being processed, moisture content monitoring is even more critical to sawmill safety.
“What is the Mountain Pine Beetle? A Primer for Teachers & Students” Parks Canada: The Government of Canada.
“The Facts on Mountain Pine Beetle and Cold Weather” Sustainable Resource Development: Government of Alberta.
“Mountain Pine Beetle” Naturally Wood: British Columbia Forest Facts. Ministry of Forests, Lands and Natural Resource Operations: Government of British Columbia. Victoria: September 2010.
MacLeod, Andrew “Milling Mountain Pine Beetle Wood May Pose Fire Risk.” The Tyee. Vancouver, BC: April 24, 2012.
“Mountain Pine Beetle: A Climate Change Catastrophe.” YouTube, Inc.
[i] Safranyik, L., H. Barclay, A. Thomson, and W.G. Riel A Population Dynamics Model for the Mountain Pine Beetle, Dendroctonus ponderosae “. The Pacific Forestry Centre: Natural Resources Canada. Victoria, BC: 1999.
[ii] Spencer, Kent “Did Pine-Beetle Sawdust cause Prince George Sawmill Explosion?” Postmedia News. Montreal: April 27, 2012.
[iv] Kleis, Heron and Søren Dalager “100 Years of Waste Incineration in Denmark: From Refuse Destruction Plants to High-technology Energy Works.” Babcock & Wilcox Vølund A/S. Esbjerg, Denmark: 2007.
[v] Jackson, Peter L., Dennis Straussfogel, B. Staffan Lindgren, Selina Mitchell and Brendan Murphy “Radar Observation and Aerial Capture of Mountain Pine Beetle Dendroctonus ponderosae Hopk. (Coleoptera: Scolytidae) in Flight Above the Forest Canopy.” Natural Resources and Environmental Studies Institute: University of Northern British Columbia. July 2008.
[vi] Ibid.: pg. 2315.
[vii] Ibid.: pg. 2315.
[viii] Ibid.: pg. 2324.