Sun-bleached skeletons of long-dead whitebark pine trees stand at the top of a 7,200-foot-high ridge along the Reservation Divide on the Flathead Indian Reservation, Montana. With annual average temperatures in Montana rising, the whitebark pine that were not previously threatened are now facing an increase in blister rust infections, mountain pine beetle infestations and wildfire.

Stretching from British Columbia, Canada down to parts of California and east to Montana, live the whitebark pine. The tree grows in subalpine and timberline zones — elevations anywhere from 4,000 to almost 9,000 ft. It's an unforgiving space. The wind is harsh. Plants and animals confront sub-freezing temperatures, often until summertime.

The whitebark pine has historically thrived in these lands. But today, the tree species is in trouble. So much so that the U.S. Fish and Wildlife Service listed the whitebark pine as a threatened species in December 2022. Increased fire intensity from climate change and colonial fire suppression practices, infestation by mountain pine beetles and a deadly fungus called blister rust — they're collectively killing this tree.