Climate Change Takes Toll on the Lodgepole Pine

Rising temperatures, drought and the spread of destructive insect pests will shrink the North American range of the lodgepole pine nearly 10 percent by 2020, a new study finds.

The scientists behind the report said the projected decline of the evergreen species, whose range covers much of the Pacific Northwest and extends as far south as Colorado, was backed by observed ecosystem changes dating back to 1980.

The study was conducted by forestry researchers at Oregon State University and the Department of Forest Resource Management at the University of British Columbia. It will appear in the latest edition of the scientific journal Climatic Change.

“For skeptics of climate change, it’s worth noting that the increase in vulnerability of lodgepole pine we’ve seen in recent decades is made from comparisons with real climatic data and is backed up with satellite observations showing major changes on the ground,” Richard Waring, an emeritus professor of forest science at Oregon State University, said in a statement.

The tall, slender pines, once used widely by American Indian tribes as poles for teepee lodges, could largely disappear from the Pacific Northwest by the end of the century if current climate trends persist, the researchers estimated.

The lodgepole pine is just one of a number of North American tree species suffering from climate-related changes. In 2010, an estimated 100,000 spruce trees a day were toppled by a massive spruce beetle infestation in Colorado, according to a study of the state’s forests released earlier this month.

The 2010 outbreak covered nearly 210,000 acres of spruce forests in Colorado, nearly double the size of the affected area the previous year. The state also suffered the loss of hundreds of thousands of acres of lodgepole pine and aspen forests.

The threat to lodgepole pines from the destructive bark beetle has risen as decreasing snow cover and milder winters allow more of the insects to survive from season to season.

“Bark beetles in lodgepole pine used to be more selective, leaving the younger and healthier trees alone,” Dr. Waring said.

“Now their populations and pheromone levels are getting so high they can more easily reach epidemic levels and kill almost all adult trees. Less frost, combined with less snow, favors heavier levels of bark beetle infestation,” he said. “We’re already seeing more insect attack, and we project that it will get worse.”

In Colorado, the proliferation of dead trees poses the threat of uncontrollable wildfires, Tony Dixon, the Forest Service’s deputy regional forester for the Rocky Mountains, told The Durango Herald earlier in February.

“Dead zones” where the majority of trees have been killed off by beetle outbreaks are too risky for firefighters to enter on foot because of the risk of falling trees, Mr. Dixon said. Fires fed by fallen timber also burn close to the ground, rendering aerial tankers ineffective.

“We’re probably going to have to allow these fires to grow much larger than we’re accustomed to,” he said.

http://green.blogs.nytimes.com/2011/02/28/climate-change-takes-toll-on-the-lodgepole-pine/