Jim Robbins is a freelance journalist in Helena, Montana, where he has written for The New York Times for more than twenty-five years. He is also a frequent contributor to Condé Nast Traveler, for which he has written environmentally themed travel stories on Peru, Chile, Mongolia, Sweden, Mexico, and numerous other places. He has written three books, most recently on the critical role of the process of attention in human physiology and psychology.

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The beetles, experts say, will have their way and only be checked if bitterly
cold weather returns to the Rockies—which hasn’t happened since the 1980s.
While Montana has seen a million acres killed or dying, in northern
Colorado and southern Wyoming the crisis in the states’ lodgepole pine forests
is historically unprecedented.
“We’re seeing exponential growth of the infestation,” says Clint Kyhl,
director of an incident-management team in Laramie, Wyoming, set up to deal
with the crisis caused by the huge swath of dead forests in northern Colorado
and southern Wyoming. 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 2 million.
In the next three to five years, Kyhl says, virtually all of Colorado’s
lodgepole pine trees over five inches in diameter will be lost, about 5 million
acres. “Already, in many places every lodgepole over five inches is dead as
far as the eye can see,” he says. (There’s not enough food in a tree to sustain
the beetles if it’s less than five inches tall.)
Lodgepole pines are largely confined to high altitudes. But the beetles
have moved into ponderosa pine forests on Colorado’s Front Range, Kyhl
says, which means they could kill forests around homes in the densely populated
region.
In the Canadian provinces of British Columbia and Alberta, the problem
is most severe of all, the largest known insect infestation in the history
of North America, according to officials. British Columbia has lost more
than 34 million acres of lodgepole pine forest, and a freak wind event last
year blew beetles over the Continental Divide to Alberta.
Cold weather always kept the beetles from crossing over. To keep the
bugs in check, several days of temperatures that touch forty below zero are
needed. But warmer temperatures and the wind changed the beetles’ range,
and experts fear they could travel all the way to the Great Lakes.
So many trees have died in British Columbia, and so much carbon from
the dying trees has been released into the environment, that experts say the
forests have gone from a carbon sink to a carbon source.
The death of the forests worries the tourism industry across the West.
Because of the hazard of falling trees, many ski areas have had to cut down
their forests and revegetate. At Vail Resort, for example, which has been
particularly hard-hit, workers have removed thousands of dead trees and
planted new ones.
The dead trees that blanket the mountains are shifting ecosystems as
well. In Yellowstone, for example, the beetles are killing the whitebark pine
trees, which grow nuts rich in fat that are critical to grizzly bears. Biologists
say streams will flood because live trees will no longer catch snow and allow
it to slowly melt, and thus the epidemic could injure salmon.