Ancient Forests at the Skyline
by Jason D.B. Kauffman, Sun Valley Magazine, Summer 2006
They exist equally as well on the margins of the West’s high, untamed landscapes as they do on the peripheries of our imaginations. They lead solitary lives often spanning 1,000 years or more.
Perched on the rugged edge of the skyline in the Rocky, Cascade and Sierra Nevada mountains they survey wild nature at its finest: vertical, pristine, and free. They are Pinus albicaulis, the whitebark pine tree, a species as close to immortal as can be found on this earth.
The whitebark pine occupies a harsh and uncompromising world. Gale force winds bend its trunk and branches into twisted, tortured shapes. The tree’s thick roots reach far and deep in search of every available nutrient in the dry, rocky soils.
Whitebark pine are typically the highest elevation trees and are found on solitary perches, in open, park-like forests, and in mixed stands with other species of trees. In central Idaho, the characteristically round, squat trees are found at the tree line in every major mountain range.
The whitebark is perfectly suited for its harsh and high altitude surroundings, being both resilient and hardy. Small wonder people drawn to high, wild places find them so appealing.
Humans aren’t the only ones drawn to whitebark pine trees, however.
Throughout the year numerous species of wildlife take advantage of what the whitebark pine has to offer. Buried within each of the whitebark pine’s deep-purple cones is an abundance of small pea-sized seeds. Because the seeds are comprised of 52 percent fat, grizzly bear, red squirrels, and other wild critters gorge themselves on the seeds in autumn.
Another species drawn to the whitebark pine is the jay-sized Clark’s Nutcracker. The unique symbiotic relationship between the Clark’s Nutcracker and the whitebark pine is a story truly worthy of telling.
Like other related “stone pines” in Europe and Asia, the North American whitebark pine relies on the intervention of a Nutcracker to open its cones and release the seeds within. While other animals also harvest the seeds of the whitebark pine, only the Clark’s Nutcracker has the ability to harvest and dispatch them in the soil in a manner suitable for germination and the establishment of seedlings.
Clark’s Nutcrackers are known to harvest between 35,000 and 100,000 whitebark pine seeds in a typical year. Like others of the genus Corvus (crows and ravens are also members)—the Clark’s Nutcracker is an extremely intelligent bird. Studies have shown that Clark’s Nutcrackers employ an extraordinary method of using downed logs, large rocks, and other stationary objects to mark where they’ve placed their seed caches.
Even the Clark’s Nutcracker is susceptible to memory lapses, however, and often fails to recover all of its seeds. Over time, a few of these forgotten seeds germinate and send little fragments of green poking up through the warming springtime soils.
The whitebark pine’s broad, sweeping limbs provide an abundance of shade, much more than the subalpine fir, Douglas fir, and spruce, species of trees often found within the context of a whitebark-dominated forest. Unlike those narrow cone-shaped trees, the expansive shade provided by whitebark pines helps retain winter snows well into the summer months.
The deep-rooted whitebark pine also acts as an anchor, preventing highly erodible soils from washing away with the springtime snowmelt.
Stanley resident Dana Perkins, Ph.D., is an ecologist with the Challis Field Office of the Bureau of Land Management (BLM). Perkins’ work takes her high into the Sawtooth-Salmon River region’s mountains to track the condition of local whitebark pine forests suffering from another type of outbreak, albeit a natural one.
If you’ve driven anywhere in the Sawtooth Valley of the Sawtooth National Recreation Area (SNRA) in recent years, you’ve likely seen the red-needled handiwork of the mountain pine beetle. The infestation, which currently affects stands of lodgepole pine and whitebark pine throughout the SNRA, is just the latest chapter of a constant ebb and flow. Mountain pine beetle infestations typically occur in an 80- to 100-year cyclical pattern.
The mountain pine beetle feeds in the phloem layer of the inner bark of trees in both the adult and larval stages. Boring dust around the base of a tree and pitch tubes that look like polka dots on the trunk, are evidence that beetles are attacking it. The feeding leads to the eventual demise of the host tree. In time, beetle infestations die down as the beetle’s food sources begin to run out.
Beetles typically don’t attack small-diameter trees. Some speculate that this is due to diminished food supply, and the beetles’ susceptibility to extreme cold, which are characteristic of small-diameter, poorly insulated young trees.
In her work Perkins uses dendrochronology, or tree-ring dating, to analyze growth patterns of whitebark pine stands in central Idaho. As a master’s student in 1992, Perkins used dendrochronology to establish the date of the last major mountain pine beetle outbreak to hit the Northern Rockies region from 1920 through 1940.
Perkins’ research helped explain the significance of the bleached white and gray stands of whitebark pine—still-standing remnants of the 1920 to 1940 beetle outbreak—that can be found in many locations throughout Idaho and surrounding states. Perkins and other forestry experts call these silent reminders of past beetle outbreaks the “gray ghosts,” or “ghost forests.”
Perkins’ thesis work led to an additional discovery of singular significance. On a west-facing slope in the White Clouds, Perkins and her advisor, Dr. Tom Swetnam, came across a whitebark pine they dated to 726 A.D., making it the oldest known whitebark pine anywhere.
A number of factors determine when outbreaks of mountain pine beetle happen, and the intensity of outbreaks, Perkins says.
Variables affecting the current outbreak include the density of lodgepole pine stands, the 80- to 100-year-old age of the stands, and may include the extended drought the region is experiencing.
The beetle outbreak isn’t limited to Idaho.
“It’s not local, it’s regional,” Perkins says. “It’s moving around and extending into surrounding states.”
Perkins speculates that global warming may also be a contributing factor to the success of mountain pine beetle in whitebark pine and lodgepole pine stands today commenting, “it makes it easier for the beetles to make it through their life cycle.”
Perkins isn’t surprised at the recent outbreak of mountain pine beetle, especially in the SNRA’s lodgepole pine forests. “It’s time for it to occur. The stands are dense enough and the lodgepole pines are of the right age.”
Perkins is currently conducting a study looking into a method of repelling mountain pine beetle from whitebark pine stands using natural pheromones that signal beetles to stay away from particular stands of trees. The pheromones trick the beetles into thinking there are already enough beetles in the trees, she said.
Perkins’ project, located on BLM land near the confluence of the East Fork and Main Salmon rivers, is producing promising results, and she hopes to continue gathering data through the course of the outbreak.
Robin Garwood, a wildlife biologist for the SNRA, is collecting information in order to address the other major threat to whitebark pine: fire suppression.
Historically, fires in lower elevation forests have spread into upper elevations or started within these upper elevation forests and impacted whitebark pine communities, says Garwood. The fires create openings that Clark’s Nutcrackers are known to select as caching sites.
Whitebark pine is a seral species, meaning they’re typically the first tree species to come in after a disturbance like fire. Without wildfire in the equation, however, the openings in whitebark pine forests have become fewer. A sign that fire hasn’t been allowed to do what it does is the increasing numbers of trees such as subalpine fir, Douglas fir and spruce beginning to crowd out whitebark pines, Garwood says.
The answer, and what Garwood is currently working on, is the reintroduction of fire to the whitebark pine landscape. Garwood has applied for federal funding to begin moving beyond planning and actually start initiating small, prescribed burns in areas where subalpine fir has encroached into whitebark pine stands in the SNRA.
Based on the success of the prescribed burns, the project could eventually be expanded into more and larger areas, she says.
Many researchers, Perkins included, believe the role of humans is essential to the future of the whitebark pine. Projects like the planting of whitebark pine seedlings on Bald Mountain at Sun Valley offer the species hope, she says. “It’s visible to the public and you can tell their story,” Perkins says. “It’s a natural classroom.”
Without human intervention, white bark pine could become locally extinct over much of its historic range, Perkins says. “It’s going to take humans working on it. It’s a species we should be concerned about. Everybody loves them.”
Later this summer the importance of central Idaho for the whitebark pine’s future will take center stage when the Whitebark Pine Ecosystem Foundation’s annual meeting is held Sept. 29-30 at the Community Campus in Hailey. A field trip is planned for Galena Summit on Saturday, Sept. 30. More information can be found at www.whitebarkfound.org or by calling Dana Perkins at 208.879.6243.