A Day in the Field
By Elizabeth Pansing
Graduate Student at University of Colorado, Denver
Early in the morning, often before the sun rises, our group of researchers piles into a well-loved pickup and drive a gnarly 2-track road to White Calf Mountain in Glacier National Park. Leaving the truck at the park boundary, we hike partway up the mountain through fields of Indian paintbrush, lupines, and wild geraniums. After this brisk ascent — no matter how many times we hike it, I am always breathless when we arrive at our destination — we look back toward the plains east of Glacier National Park and south to the continuation of the Lewis Range. The spectacular scenery is occasionally punctuated by the howl of wolves, making it more wild and awe-inspiring. But the views aren’t what brought us here. We are here for the old, gnarled sentinels that watch over this mountain and many others of the western United States and Canada: the whitebark pine.
If you’ve ever hiked or played in the subalpine and treeline forests where whitebark pine grows, you’ve likely witnessed the rugged beauty of these trees. They withstand harsh temperatures, heavy winds, sun exposure, and many other environmental challenges to grow on exposed ridges and at the highest elevations where many conifer species can’t survive.
In the overwhelming beauty of this landscape, the portents of doom are easily overlooked. We know better. The whitebark pines are dying. If you stop and look closely, many of the branches and trunks are covered in blisters that release powdery spores that look like instant macaroni and cheese powder. These blisters are the result of a disease called white pine blister rust, caused by an invasive fungus that, in some areas, now infects up to 100 percent of the trees. This pathogen was introduced from Europe in the early 1900s in shipments of eastern white pines. Combined with mountain pine beetle outbreaks exacerbated by climate change and fire suppression policies, white pine blister rust has devastated whitebark pine populations nearly range-wide. As we go about our daily activities, we are lucky to find a single tree that is healthy.
This is not only bad news for the whitebark pine, but also for these ecosystems as a whole. Whitebark pines are the keystone of this environment. Their fatty, nutrient-rich seeds provide food to many types of wildlife including grizzly bears. They help the ecosystem recover after disturbances like fire and promote the growth of other trees. Whitebark pine even protracts the snowmelt that later becomes our water supply. Because of their integral role, the disappearance of loss of whitebark pine would threaten the continued function of these ecosystems. The rapid population decline has prompted the U.S. Fish and Wildlife Service to designate whitebark pine as a candidate for listing under the Endangered Species Act.
Luckily for us, our research allows us to search for more hopeful tidings. After catching our breath, the day begins. We are looking for young whitebark pine, those that germinated from seeds we planted last summer.
Last year, we acted like Clark’s nutcrackers — birds that have an unusual relationship with the whitebark pine. The two are co-evolved mutualists; the tree is completely dependent on the bird for its seed dispersal because, unlike many other pines, whitebark pine cones do not open when the seeds are ripe. Instead, the cone scales stay sealed, trapping the seeds inside. The tree needs the nutcracker’s help to free the seeds so they can make it to the ground to regenerate. In the late summer and early fall, nutcrackers harvest whitebark pine seeds, place them in a specialized pouch under the floor of their mouth, and transport them as far as 20 miles before hiding them in ‘caches’. These groups of up to 15 seeds will be a food source for the birds and their offspring throughout the coming winter and spring when food is scarce. They cache in a variety of locations — near rocks, at the base of trees, in open meadows, and in closed canopy forest; they even place them in trees. Researches have estimated that nutcrackers create between 9,500 and 30,600 of these caches each year — many more seeds than they need to survive. Those caches they happen to forget or fail to retrieve can go on to germinate and contribute to a new generation of trees.
When we acted like nutcrackers, we created more than 700 caches here and in another location in the Greater Yellowstone Ecosystem, mimicking their behavior by caching seeds in locations similar those they use, using a similar number of seeds, and burying them at a similar depth in the ground. We left the caches for the winter and returned this year to check each of them for germination.
Our team scrambles over rough terrain and spends long hours navigating to our caches. In many spots, we fail to find the seeds — they’ve been taken from caches by mice or chipmunks — or we find seeds that are moldy or sun-scorched. But in some cases, we find what we’ve been hoping for — whitebark pine germinants! We catch some just as they are emerging, some that have been up for a week or so, and others that have already ended their short presence on the landscape — killed by sun scorching, browsed by birds or other animals, or stuck in the soil and unable to emerge. There are many caches without germination, but, more importantly, we see signs of regeneration.
Unfortunately, in hard-hit areas like White Calf Mountain, we can’t rely on natural regeneration alone to sustain these ecosystems. Because of the number of dead and dying trees, the number of cones has decreased. This leads to declines in seed availability and fewer visits by nutcrackers, resulting in reduced regeneration. In these areas, the whitebark pine needs our help. Conservation and restoration efforts are ongoing, but there is much more to be done.
As the sun begins to slink behind the mountain, we begin our return to the truck. While there are challenges ahead and the outlook may seem bleak, these seedlings give me hope that the trees are willing to keep trying if we are.