Rapid rise in wildfires in large parts of Canada?

[Bob Wallace]

1. Dead trees are easy to burn...

"From New Mexico to British Columbia, the region’s signature pine forests are succumbing to a huge infestation of mountain pine beetles that are turning a blanket of green forest into a blanket of rust red.

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.

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.

The beetles will only be truly checked, experts say, if temperatures that used to reach 30 and 40 below for weeks return to the Rockies, temperatures that have not been seen in decades."

http://www.nytimes.com/2008/11/18/science/18trees.html?pagewanted=all