Reprinted from Land Letter with permission from Environment & Energy Publishing, LLC. www.eenews.net

By Laura Petersen, E&E reporter

For millennia, whitebark pine trees have held firm to the cold, rocky timberlines of the northern Rockies, Cascades and Sierra Nevada, providing shelter, food and other ecosystem services for mountain wildlife.

But before long, the hardy, snow-battered tree whose nutritionally dense seeds are a delicacy for grizzly bears, red squirrels and mountain birds may become functionally extinct.

In numerous reaches of Idaho, Montana, Wyoming and southern Canada, whitebark pine trees have declined by as much as 90 percent, experts say, and their prospects for recovery seem to be growing dimmer by the year.

“It’s going and it’s going fast,” said Bob Keane, a research ecologist with the Forest Service’s Missoula Fire Sciences Laboratory in Montana. “It’s working itself from the north to the south to Yellowstone.”

The culprits are a deadly pair of natural enemies: blister rust, an invasive fungus that infects whitebark pine and other “five-needle” pine species of North America; and the mountain pine beetle, whose spread to high-elevation forests has been aided by a warming climate.

As conditions further deteriorate for whitebark pine, pressure is mounting on the Fish and Wildlife Service to add the tree to the federal Endangered Species List. A listing decision could come as soon as next July, when federal biologists complete a status review of the species.

Blister rust and pine beetles are killing vast stands of whitebark pine trees. Nuts from the tree are an important food for red squirrels, birds and bears. (Richard Sniezko/USFS — click to enlarge)

That review was prompted by a 2008 listing petition from the Natural Resources Defense Council, followed by a lawsuit and subsequent finding by federal regulators that NRDC had presented enough scientific evidence of whitebark pine’s imperiled status to warrant a formal ESA review (E&ENews PM, July 10).

NRDC became interested in whitebark pine while working to relist grizzly bears in the greater Yellowstone area as a threatened species, said Sylvia Fallon, an NRDC ecologist. The tree’s seeds, which are stored inside pine cones, are a high-fat food source for the bears.

“Our idea in filing the petition was to raise the profile of this tree and what’s happening to it with climate, and draw attention to the broad-scale ecosystem changes that are happening,” Fallon said.

Ann Belleman, the FWS biologist overseeing the review, said regulators are moving swiftly to make a final listing decision by July 2011, but they are challenged by incomplete data on the complex species.

“There are still many, many gaps,” Belleman said of the scientific literature.

KEYSTONE SPECIES

A noncommercial species, whitebark pine has received less attention, funding or research interest than other, more commercially viable trees.

But a small group of scientists that has been monitoring whitebark pine for decades, including Keane, who literally co-wrote the book on the species, believes the tree may have more to say about the health of mountain ecosystems than any of its peer species.

“I can’t think of another tree that plays such an important role for so many other vertebrates; so many other animals are so dependent on its seed,” Keane said.

Biologists view whitebark pine as a “keystone species” for sub-alpine ecosystems because its seed provides food for so many animals, including grizzlies and black bears, Clark’s nutcrackers and red squirrels. Whitebark also helps other plants get a foothold in the rocky soil, which in turn provides nourishment for even more animals.

But the benefits are not limited to wildlife — the trees also shade snowpack and slow the pace of snow melt into the summer months, gradually releasing water that is consumed by millions of people.

Keane said the contrast between an area with whitebark pine and one devoid of the tree can be stark.

“When you lose the species, everything else starts to go downhill,” Keane said. “Sure, you’ll get another ecosystem, but it won’t nearly have the diversity that whitebark pine will.”

Whitebark pine has long been shielded from threats like disease, pests and harmful invasives by its harsh terrain, but certain invaders have managed to overcome the tree’s natural advantages.

White pine blister rust, for example, was introduced from Europe to North America a century ago. It subsequently spread across the entire range of white pine forests. But many trees still managed to survive, with some species developing natural resistance mechanisms, such as dropping infected needles to prevent spreading, or quarantining the disease in a section of bark, said Sally Long, the orchard manager at the Forest Service’s Dorena Genetic Resource Center.

But where blister rust left some pine forests intact, the mountain pine beetle plowed through the remaining healthy stands, migrating from lower-elevation forests to the harsher terrain preferred by whitebark pine as temperatures warmed. Defenseless against the invading beetle, whitebark pine began an even steeper decline.

But biologists like Keane are not ceding whitebark pine to the graveyard of extinct species.

In fact, he said, whitebark pine will probably never go extinct across its entire range. Rather, “it’s the whitebark pine forest that is gone.”

“This doesn’t mean we can’t restore [whitebark pine], it just means we’re going to have to invest a little more money than we thought,” he said.

RESTORATION EFFORTS

Keane and others have been researching restoration methods, such as using prescribed fire or cutting down other trees in whitebark pine habitat to see if the tree can regenerate in a less competitive environment.

The Clark's nutcracker feeds on whitebark pine seeds, but also disperses and buries the seeds, which then germinate and grow. (Dave Menke/USFWS — click to enlarge)

A recent study concluded there were insufficient pine seeds for the Clark’s nutcracker — which both eats and distributes whitebark pine seeds in small underground caches — to perform both of its ecological functions.

Where bird-deposited seeds have been insufficient for whitebark pine to regenerate naturally, foresters have tried planting seedlings to restore habitats. But there too was a major problem — historically, there have not been enough blister rust-resistant seedlings to plant.

To overcome this problem, researchers have been collecting seeds from the hardiest trees, growing them in nurseries and testing them for rust resistance. The process takes both time and patience because whitebark pine has a six-year growing cycle.

So far, seedlings have been planted in less than 1 percent of restorable whitebark pine habitat, Keane estimated. But prospects for large-scale replanting by federal agencies are strong since 98 percent of the whitebark pine’s range in the United States is on public land, including national parks and forests.

“All the national agencies are all for it, they’d do it in a second if they had the money,” Keane said.

Raising a whitebark pine seedling costs 90 cents to $1.50, which is three to 10 times more than the cultivation costs for other species, Keane said. Getting the seedlings to high-elevation ridges, which are far from roads, also requires significant effort, including the use of helicopters. Altogether, Keane estimates a comprehensive restoration program would cost between $1 million to $2 million a year.

Restoration also raises other thorny land management questions.

For example, tree planting is not allowed in wilderness areas, though about 50 percent of the whitebark pine range in the United States is within designated wilderness. Fire management — or the lack of fire management — in such areas poses equally difficult questions that must be addressed before a restoration program can begin in earnest.

In the near term, Keane said, foresters have adopted some novel methods to protect healthy but isolated populations of whitebark pine, including rubbing the trunks of healthy trees with pheromones that trick mountain pine beetles into thinking those trees have already been infected.

“I firmly believe we have the technology to do it right now,” Keane said. “And all we need is the will.”

READ OR DOWNLOAD the Natural Resources Defense Council petition to list the whitebark pine tree as an endangered species.

Print Friendly

Page — 1 2

Published on December 14, 2010

Previous post:

Next post: