I stand on a ridge of the Snowcrest Mountains in Southwestern Montana. From here I can see nearly a dozen other mountain ranges, including the snowy peaks of the Tetons in the distance. I look down at my feet and find myself just as amazed as I am by the vast vistas. The subalpine hills are blanketed in color: indigo of sky pilot, magenta of shooting star, periwinkle of forget-me-nots, and yellow of alpine sunflower. It’s June in Montana and everything is full of life. Everything, that is, but one type of tree. This tree’s dull gray color stands in stark contrast to the dark green pines around it and the vibrant spectrum of countless wildflowers. This tree is the color of ash, the color of death. From the ridge, over 9,000 feet high, I look down at hillsides covered in these gray trees. Someone remarks that it looks like a graveyard. It is a graveyard I think as my eyes roam over the expansive cemetery. I wonder why this tree alone lacks the life that the rest of this majestic mountain range holds. It doesn’t take long for me to realize that I already know the answer: these trees are white bark pines, a species that is presently in a state of rapid decline. In fact, mortality in this region is likely around 95%.
I look up to see two Clark’s nutcrackers flying overhead and am reminded of their role. Their long thick beaks are designed to pick out the seeds from whitebark pinecones. Squirrels, too, eat these seeds, storing large piles of them in preparation for winter. This is why I observe a stand of multiple white bark pine trunks lumped together while others stand alone. These trees were planted long ago by Clark’s nutcrackers who bury seeds in the fall and return for them in the spring when food sources are scarce. The large pines, white and gnarled, remind me of old men, whose age inspires respect. Whitebark pines, which can live for over a thousand years, deserve equal appreciation. Their long life span makes recent whitebark mortality even more curious. However, this loss is not a mystery—we know who the killers are. White pine blister rust, mountain pine beetle, wildfire suppression, and climate change are often considered the main causes of recent white bark pine decline.
Blister rust is a non-native species that came to the U.S. over a century ago. A plant parasite, this fungus requires two plant hosts to survive, one of which is the white bark pine. Our second night in the Snowcrests we camped near a few rare living whitebark pines. On them I could see the signs of blister rust infection: swollen limbs and small lesions. Investigating this foreign fungus I poked at a branch speckled with lesions; a neon-orange powder spills onto my fingers. Soon my hands are covered in this strange dust, and I silently hoped that blister rust cannot be passed onto humans. I also notice a few high branches that appear to have been gnawed on and learn that animals like the taste of infected trees. I suddenly have the sympathy for this poor tree, not only plagued by disease but by pesky rodents as well. The chance of survival is probably slim. However, blister rust wasn’t always quite so deadly. In the past, it may have caused as little as 10% mortality in some areas. That rate has spiked in just that past few decades—the same years in which we’ve started to become more aware of warming temperatures. It’s clear that climate change involves shorter winters and hotter summers in some places. This result of warming temperatures can dry out and weaken the white bark pine in its lower elevations.
The mountain pine beetle is another contributor to white bark pine decline. This insect bores into pine trees to lay its eggs, causing damage that kills the host. Mountain pine beetles have swept through the northwestern part of North America, causing extensive damage to forests across the region. Many trees, such as the lodgepole pine, have elaborate defense mechanisms to protect themselves from the beetle. Whitebark pines, on the other hand, appear to have limited defenses. Climate change is also a potential underlying cause of this problem. In the past, pine beetles have been unable to reach high elevations where white bark pine grows. However, as the earth gradually warms, the pine beetle can now survive at these higher elevations and can attack the vulnerable white bark pine. A warmer climate in general stresses the trees, making them weaker and less likely to survive damage from both pine beetle and blister rust.
Wildfire suppression is also detrimental to white bark pine. It allows spruces and firs to flourish, outcompeting the white bark pine, which needs lots of sunlight and open space to reproduce. Between blister rust, mountain pine beetle, wildfire suppression, and the ever-present threat of climate change, the white bark pine is under attack from all directions. It has little defense and no way to escape. Moving to higher elevations in many areas isn’t even possible—above its current habitat the alpine slopes are often too rocky for growth.
So, we know what is causing recent white bark pine decline, but why should we care? Such widespread death of any species is concerning, but it is especially problematic in this case because white bark pine is a keystone species. A keystone species is one that many other species and processes in an ecosystem rely on for survival. The grizzly bear relies on white bark pine nuts as a food source, raiding seed piles forgotten by squirrels. As people debate the grizzly’s status as an endangered species, white bark pine decline is being considered. This is just one part of a very complex ecosystem. I’m learning more and more how difficult it is to fully comprehend all the complexities of large landscapes.
The countless meadows of forget-me-nots make the Snowcrests backpacking trip unforgettable, but the hillsides of dead whitebark pines do as well. This is one example of what makes a course with the Wild Rockies Field Institute (WRFI) such an incredible learning experience. I could learn about this issue during a lecture or read about it online, but that wouldn’t give me the ability to fully grasp the extent of it. At elevation of only four thousand feet, the university is far-removed from the home of white bark pine. Backpacking through this area gives me the opportunity to see first-hand the magnitude of white bark pine mortality, to touch its swollen branches, to walk through a forest of dead and dying trees. WRFI allows us to truly experience what we are learning about—creating a more meaningful education.
Climate change is a difficult subject to comprehend because it is not something most people see on a daily basis. The carbon cycle, greenhouse gasses, and rising sea levels are practically invisible. Like observing shrinking glaciers, seeing the magnitude of white bark pine death forcers me to think about the impacts of climate change more than I ever have before. I am awestruck and suddenly inspired to study climate change more extensively. I think I’m finally beginning to discover what I am most passionate about.