Mountain pine beetles decimate western forests

Jim Robbins writes in the NYT about the mountain pine beetle infestation sweeping through pine forests in western North America.

In Wyoming and Colorado in 2006 there were a million acres of dead trees. Last year it was 1.5 million. This year it is expected to total over two million. In the Canadian provinces of British Columbia and Alberta, the problem is most severe. It is the largest known insect infestation in the history of North America, officials said. British Columbia has lost 33 million acres of lodgepole pine forest, and a freak wind event in 2006 blew mountain pine beetles, a species of bark beetle, over the Continental Divide to northern Alberta. Experts fear that the beetles could travel all the way to the Great Lakes.

Dendroctonus ponderosae is native to North America, so this isn't an example of the all-too-common story of "exotic species gone wild." Instead, it seems to reflect the growing reality of just how far out of balance our relationship with the land has become and how long we will have to live with the reprecussions of our poor choices.

Foresters say the historic outbreak has several causes. Because fires have been suppressed for so long, all forests are roughly the same age, and the trees are big enough to be susceptible to beetles. A decade of drought has weakened the trees. And hard winters have softened, which allows the beetles to flourish and expand their range.

Fire suppression during the 20th century and climate change in the 21st (owing its momentum to the Industrial Revolution that began in earnest in the 19th). I fear that this will be a common refrain for the next several decades. It's a good example of why a precautionary principle guided by ecological knowledge is so important. It will be thousands of times more difficult to pick up the pieces on this kind of collapse than to have prevented it in the first place.