2008-07-10

Pine beetles eat Canada, boosting GHG emissions

The mountain pine beetle, a small tree-devouring insect, has deforested an area of British Columbia the size of Louisiana — over 130,000 square kilometers. The 5 millimeter insect is a perfect tree-destroying machine. The beetles bore through the tree's bark to reach the phloem of the tree, which contains the tree's organic nutrients. The beetles then feed on these nutrients and lay their eggs. The trees defend themselves by secreting extra resin, but the beetles are often able to combat this by releasing a blue fungi. In about two weeks time, the tree turns a tell-tale red and essentially starves to death. The mountain pine beetles move on.

The mountain pine beetle, like forest fires, is a part of the natural cycle of a forest. However, the current outbreak is abnormal in its scale. Usually fire and winter cold snaps keep the beetles under control. But intense forestry management has meant a dearth of forest fire. Combined with a long series of unseasonably warm winters, the beetles have been spreading further and further every year. Many blame the warm winters, and therefore the scale of the infestation, on climate change. There was hope that this winter — which was colder than many previous — might stop the beetles, but so far it doesn't seem to have been effective as scientists hoped.

British Columbia is not the only victim — in 2002 the beetles reached Alberta. According to an article in The Economist, the beetles have now entered the parks of Banff, Jasper, Kananaskis, and have traveled as far as Slave Lake in the central-north of the province. The beetle has also made its way south into the American west, attacking Colorado forests vigorously, with 6,000 square kilometers falling victim so far.