The decline of whitebark pines threatens the Greater Yellowstone Area, as researchers search for solutions.
KARL BUERMEYER STOPS HIS WHITE PICKUP ON THE SIDE OF A dirt road and motions to a few whitebark pine trees rising from a mat of pinkish-purple fireweed. On one of the tree trunks, there's a scar of missing bark. Thick streams of now-solidified sap have spilled over the wound. A non-native fungus brought over from Europe called blister rust made a sugary canker that rodents subsequently gnawed away - hence the missing bark. Everything above the point of infection will eventually die, including the tree's cones. If the tree can't produce cones, it no longer contributes its genes to the landscape and is considered by researchers and forest managers to be ecologically dead.
Back in the pickup, Buermeyer, a vegetation manager for Bridger-Teton National Forest, drives deeper into the heart of the Mount Leidy Highlands, an area just east of Grand Teton National Park in northwest Wyoming. This is wild country. Most of the peaks range between 8,000 and 10,000 feet, and the area is thick with predators such as grizzly bears, mountain lions, Canada lynx and wolves, along with prey species like elk, moose and deer.
As Buermeyer drives, the forest opens, and large patches of fireweed give way to sagebrush, which in turn give way to groves of aspen and finally to forests of lodgepole pine, subalpine fir and spruce. Occasionally, whitebark pine branches - each branch sporting a pair of dark-purple cones at its tip - stretch skyward. But among the healthy conifers, dead trees are readily apparent.
A broad, high-elevation valley appears, and we get our first good look at the scope of the devastation. Beetle-killed pines - called ghost trees because of their gray trunks and branches denuded of needles - stand among the live spruce and fir. An entire west-facing slope of Mt. Leidy is covered with dead whitebark. In the Rocky Mountains from Colorado into Canada blister rust has conspired with native mountain pine beetles against high-elevation forests, leaving massive destruction in their wake.
At risk is an iconic American landscape. The 20-million-acre Greater Yellowstone Area- a region of mostly contiguous habitat in Idaho, Montana and Wyoming - is one of the last ecosystems with a full complement of flora and fauna in the lower 48 states. Whitebark pine sits atop that ecosystem, serving as the anchor for high- alpine and watershed habitats and as food and shelter for species ranging from Clark's nutcracker to the grizzly bear.
As of 2009, about 95 percent of Greater Yellowstone's whitebark pine habitat had experienced some mortality, says Dr. Jesse Logan, a retired entomologist with the U.S. Forest Service. Fifty percent of the ecosystem's whitebark "have been impacted to the point where you lose ecosystem function," Logan says.
The loss of ecosystem function means snow will melt faster, causing more runoff in the spring and less water in creeks and rivers during the summer. Grizzly bears, which rely on the seeds to build up fat for the fall and winter, will likely seek more food near the valleys, putting them in danger of conflicts with humans. Whitebarks will no longer anchor soils and provide protection for other high- elevation plant species.
While researchers, environmentalists and land managers have rallied to save the species, the outlook is grim. "The bitter irony is that just as we're learning about how important whitebark pines are, we're losing them," says Louisa Willcox with the Natural Resources Defense Council (NRDC). "That is a heartbreaking thing to realize."
In the early 1900s, blister rust - which only infects five-needle pines, like whitebark - entered the United States by way of ships that brought the fungus on white pine seedlings from Europe.
"This organism has what is considered the most complicated life cycle on the planet," says Dr. …