In a healthy natural forest, periodic lightening strikes touch off scattered fires, creating open spaces (future fire breaks) for new, vigorous species of trees to take hold. In the late 1800s and ear…
In a healthy natural forest, periodic lightening strikes touch off scattered fires, creating open spaces (future fire breaks) for new, vigorous species of trees to take hold. In the late 1800s and early 1900s, huge areas of BC were naturally burnt out, new seedlings took root, and slowly matured. As a result, the blanket of provincial forest began to thicken.
Enter Smokey the Bear and the unquestionable doctrine of preventing all and any forest fires at all costs. Rather than the millennium old cycles of periodic burning and purging, a century of relentless fire suppression across North America left intact huge sprawls of aging and very dense pine forests matted in deep, dry underbrush. In the late 1990s, BC boasted forests that were three times the volume and size of the forest cover of a century earlier. The table was set.
Enter climate change and the Mountain Pine Beetle. As the world warms, the severe winters that normally keep the MPB in check falter and lose their icy punch. The current MPB infection began in 1993 in Tweedsmuir Park in west-central BC, the bugs gorging on the unprecedented volumes of their normal ‘prey’ (aging and/or stressed lodgepole pine trees). The gathering armies sailed through the milder winters and burst out in 2000. Today the MPB has engulfed more than 13 million hectares of pine forest, killing trees right across the age spectrum.
In healthy open forests, periodic fires (usually sparked by lightening) sweep along close to the ground, clearing off the underbrush and fallen trees, scarring but not killing the larger trees. However, when choked with decades of underbrush, packed with trees and riddled with the dry, standing dead, what should have been a cleansing ground fire, transmogrifies into catastrophic firestorms.
As dead trees rot and/or burn, they release carbon dioxide. According to a recent Canadian Forest Service (CFS) report, the MPB infestation in BC alone will vent an extra billion tones of CO2 gas into the atmosphere (or about 270 million tons of carbon) by the time the beetle attack finally peters out (maybe) by 2015 or so. This is five times the amount of CO2 released per annum by Canada’s motor vehicles and aircraft. A good portion of the “new” carbon will be recycled back into new growth.
Call it food for rot, but green trees form a living carbon reservoir that “soaks up” greenhouse gas. An unnatural amount of dead trees add to the problem.
Print this page
