CRF Blog

The Bug That’s Eating the Woods

by Bill Hayes

In The Bug That’s Eating the Woods, National Geographic reports that pine beetles are ravaging forests, as they thrive in the new warmer climate.

Across western North America, in millions of acres of pine forest, the story is the same. Drive through parts of Colorado, and you’ll encounter entire mountainsides painted with rust. From valley bottoms all the way to the tree line, nearly every single pine has been killed by an enemy smaller than a thumbtack: the mountain pine beetle. Tour British Columbia, and the scale of destruction is even more appalling. More than 44 million acres of pine trees there, an area the size of Missouri, have been attacked to varying degrees over the past 15 years.

Nature is always changing. But the mountain pine beetle is a troubling omen. It shows that global warming can push even native species to go rogue. At some point the epidemic will run its course, leaving a wake of ghost forests and altered ecosystems. “We need to see this as a harbinger of what’s to come,” Six says. “We’re going to see one ecosystem after another begin to tip.”

Unlike other organisms that have been ravaging the American landscape — Asian carp, kudzu — the mountain pine beetle isn’t an immigrant. It’s native to western pine forests, especially lodgepole and ponderosa forests, where it normally lives in relatively small numbers, killing a tree or two here and there. It’s been normal too for the beetle’s population to boom every now and then, and for it to kill large swaths of forest. But mainly in a single region — not across half a continent.

The scale of the current epidemic is unprecedented. Since the 1990s more than 60 million acres of forest, from northern New Mexico through British Columbia, have suffered die-offs. By the time the outbreak in British Columbia peters out, some 60 percent of the mature pines in the province may be dead. That’s a billion cubic meters of wood.

The trees aren’t the only casualties. A forest die-off disrupts everything, from food webs to local economies. [more]