[whitebark pine] mortality that was associated with mountain pine beetle,” Logan says. “It was really warm for a period of time.”
Warm weather helps mountain pine beetles avoid the deep spring and fall freezes that can kill the beetle before its cells can protect themselves with a natural defense that can be described as the insect’s version of antifreeze.
By the first Intergovernmental Panel on Climate Change in 1990, Logan was running simulations on warming scenarios and whitebark. “The results indicated that, with a general warming climate, we could really begin to see problems in whitebark,” Logan says. “Both the extent and intensity of mortality — the productivity of beetles and how the tree seems unable to defend itself — all struck us from the beginning.”
“Not only is whitebark not well defended like lodgepole, but the defensive chemistry is backwards,” Logan continues. “Whitebark is high in compounds that the beetle uses to signal other beetles to focus attacks on the tree.”
By 2003, a beetle outbreak unprecedented in known human history began to sweep across the Rocky Mountains. In 2005, Canadian researchers used Doppler radar to document a beetle hatch that produced an estimated average of 4,950 beetles per hectare with a maximum of 18,600 beetles per hectare.
Environmental photographer James Balog has used time-lapse cameras in seven locations across the Rocky Mountains to document beetle infected lodgepole, ponderosa and whitebark pines. “To our absolute and utter astonishment, by the fall, we had dead trees in every picture,” Balog says.
“The most captivating time-lapse sequences go from summer to winter,” Balog continues. “You watch the tree go from green to red then a dried out, dusty orange, and then, the needles start falling off. When you get these sequences weighted down with these big snowstorms, it’s very beautiful. It’s a dichotomy of the sadness and the horror of the tree dying and this beauty.”
SAVING A SPECIES
Farther along the dirt road of the Mt. Leidy Highlands, vegetation manager Buermeyer unlocks a gate, and we head to the base of Grouse Mountain. Here, the Rocky Mountain Research Station is conducting an experiment to find out the best way to regenerate whitebark pine.
A contractor sprays a ponderosa pine to help protect the tree from mountain pine beetle damage. Credit: U.S. Forest Service Northern Region
We park and bushwhack into the forest to see one of the largest whitebarks in the Greater Yellowstone Area. Forest Service crews have marked this 96-foot-tall behemoth with spray paint and have sprayed it down with a beetle insecticide called carbaryl. This is one of several “plus trees” in the region, trees that researchers and foresters have identified as potentially being genetically resistant to blister rust.
Every year, certified climbers scale the trunks to the top of plus trees and encase the cones with metal baskets to prevent the seeds from being harvested by Clark’s nutcrackers, red squirrels and other species that feast on the cones. After the seeds mature, the climbers return, remove the baskets and harvest the seeds. The seeds then go to a greenhouse in Coeur d’Alene, Idaho, where they are raised to seedlings and bombarded with blister rust spores. The seedlings that survive are then deemed suitable for replanting.
Forest Service personnel have already planted blister rust-resistant whitebark pine trees in Caribou-Targhee and Bridger-Teton National Forests, says Liz Davy, a silviculturist and ranger with the Forest Service. American Forests has two Global ReLeaf projects assisting with the planing efforts in Caribou-Targhee this year. There’s also a rust-resistant whitebark pine seed orchard in the works for Gallatin National Forest in Montana. “In three more years, we’ll be ready to have trees planted for rust resistance,” Davy says.
Some of these rust-resistant seeds could find their way to Grouse Mountain. As we walk toward the peak, Buermeyer points to plastic flagging around the trunks of trees used to indicate test plots for the Grouse Mountain experiment.
On some plots, crews will thin the spruce and fir around the smaller whitebark pines in the understory so they can get more sun, a process called daylighting. On other plots, crews will use prescribed burns and clear-cutting to get the young whitebarks to “release,” meaning they grow tall enough to rise above the understory and start producing cones.
Ahead in the distance, Buermeyer spots a Clark’s nutcracker. The bird chatters raucously as it flits from one whitebark to another, stuffing its sublingual pouch with seeds that it will later cache in various nooks on the landscape for safekeeping. Researchers think this noisy little bird is almost entirely responsible for natural whitebark pine reproduction. “In a good cone year, [Clark’s nutcrackers] cache more seeds than they can eat,” entomologist Logan says. “Some of these seeds are not utilized, and that’s where the new trees come from.”
The problem is that the nutcracker is not nearly as reliant on the tree as the tree is on the nutcracker. “If the number of cones reaches a critical-low threshold, then the nutcracker switches to other food sources,” Logan explains. “The concern is that the wide area of mortality that has occurred with the pine beetle outbreak will be magnified by the switch of nutcrackers to other food sources.”
Therefore, another technique researchers are testing in the Grouse Mountain experiment is logging small patches of forest to create the kind of clearings where the Clark’s nutcrackers like to cache their seeds.
As we continue to climb, Buermeyer leads us out onto a ridge overlooking a broad bowl rimmed with dead whitebarks. This is where researchers hope to plant 1,000 rust-resistant whitebark seedlings.
Grizzly bear and cub in Yellowstone National Park. Credit: Xinem/Flickr
It’s hard not to get discouraged. Beyond a few trees at the bottom of the bowl, every mature whitebark pine is dead. Some of these trees were so old that they likely existed before Europeans ever set foot in the Mountain West. The most ancient whitebark pine is thought to be roughly 1,250 years old. With such a long life cycle, whitebark pines typically take 60 to 80 years to fully mature. It’s unlikely Buermeyer and I will ever see this view restored with mature whitebark pine trees.
If the current trend of a warming climate continues, the outlook is even bleaker. “Eighty years from now, most of the U.S. will not support this tree,” professor Six says. “They’ll never get to move up to the top of the mountain because the mountain pine beetle will take them out.”
Still, with the U.S. Fish and Wildlife Service’s 2011 announcement that the tree warrants protection under the Endangered Species Act, but is precluded by other, higher priority species, whitebark pine trees have gained notoriety and research dollars, says NRDC’s Willcox.
By planting rust-resistant seedlings and with other restoration activities to help the whitebark pines that already exist, researchers and land managers say there’s still time to ensure that the species maintains a presence in the Rocky Mountains.
Another rowdy, Clark’s nutcracker call brings a hint of hope. Buermeyer hands me one of last year’s whitebark pine cones picked clean of its seeds. A few steps more and I find one of this year’s cones, also picked clean, its seeds destined for a dark hole in the soil.
Clark’s nutcracker. Credit: Dan Smith/American Forests
Cory Hatch writes from Victor, Idaho; is a freelance science journalist; and serves as wildlands director for the Jackson Hole Conservation Alliance.
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Read more: American Forests Steps Up Efforts to Save Greater Yellowstone Area
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