As we pass through the mild winter of 2012, things don't look good for the whitebark pine. The mountain pine beetle continues to feast on the tree species, whose canopy is often referred to as the roof of the northern Rockies. The beetle's infestation of the trees, the Colorado State Forest Service reports, will die down only after several successive days of minus-30-degree temperatures. Thanks to global warming, it's been over a decade since we've had a cold snap like that.

Last year, these findings led the U.S. Fish & Wildlife Service to higher prioritize the whitebark pine tree as a candidate for protection under the Endangered Species Act. The service specifically included climate change among the species' many threats. That marked the first time in history that the federal government has declared a widespread tree species in danger of imminent extinction due to climate change.

Nancy Bockino (above) is a forest ecologist who is all too familiar with the plight of the whitebark pine and the wildlife dependent on it. She grew up around the trees in northern Idaho and western Montana. Now, Nancy is trying to save them in the Greater Yellowstone Ecosystem, an area spanning 20 million acres in parts of Wyoming, Montana, and Idaho. Watch this slideshow on Flickr (be sure to turn on the titles and descriptions under "Options") to learn morea about her work.

Image: Lance Downing