Inside the world of whitebarks
by Ray Ring
Whitebark pinecone-pickers are working in at least 19 national forests, three national parks and some wildlife refuges, as well as some Canadian forests, in the hope that the seeds they obtain can be used to grow whitebark pines that are resistant to white pine blister rust -- and perhaps, if the research progresses far enough, also resistant to mountain pine beetles. The whitebark pines grow very slowly, taking 60-80 years to produce a good crop of cones. A single cone contains an average of 75 seeds.
The whitebark pine ecosystem
Whitebark pines anchor a high-elevation ecosystem around the West. They catch and hold snowfall, so runoff occurs slowly, and their high-fat seeds are an important food for Clark's nutcrackers (a relative of crows), bears and other wildlife. Researchers have discovered that almost all whitebarks are planted by Clark's nutcrackers; the birds use their long beaks to pull seeds from the tough cones and then fly off to bury the seeds shallowly in the soil, in caches as far as seven miles from the origin tree. Inevitably, some of the seeds they cache are left uneaten, and germinate. A single nutcracker can hold a hundred seeds in a pouch under its tongue and cache more than 90,000 seeds during a good seed crop year. But as the whitebarks decline, the birds shift to other food sources, effectively stranding some of the remaining whitebarks with no alternative method of spreading their seeds. Also, in the Yellowstone National Park region, grizzly bears have a close relationship with the whitebarks. Pine squirrels collect whitebark pinecones in their middens, and then the grizzly bears raid the middens to get the seeds in the late summer and fall, when the bears are in hyperphagia stage, gorging to get ready for hibernation. The seeds are especially important for Yellowstone's sow grizzlies and cubs, which are driven away from elk carcasses (Yellowstone's other primary grizzly food) by the boar grizzlies.
The U.S. Forest Service nursery in Coeur d'Alene, Idaho, uses whitebark pine seeds to grow seedlings that are resistant to white pine blister rust. Seeds come from trees in the wild that show resistance. Also, the nursery exposes its seedlings to blister rust spores under high humidity, and those that survive are clearly demonstrating some resistance. With research that began in 1992, "we've learned that the whitebark has a lot of genetic diversity," and seven whitebark traits related to rust resistance have been identified, says Mary Frances Mahalovich, the lead geneticist at the nursery. The first study of the nursery stock they've produced shows that 47 percent of the seedlings are rust-resistant. Then the resistant seedlings are planted in the wild. There are already 2,900 acres of plantations growing resistant trees, on national forests in Montana, Idaho and Wyoming, and another Forest Service nursery in Oregon is doing similar work. The agency is also collecting scion from rust-resistant trees, grafting it onto rootstock and then transplanting those trees into four "seed orchards." Because both the mother (seed-bearing) and father (pollen-producing) trees in the orchards are rust-resistant, their offspring are even more resistant. The whole effort is tiny compared to the millions of acres of whitebarks that are either dying or already dead due to blister rust, mountain pine beetles and unusually destructive wildfires in 1998 and 2000. And the researchers don't know how to raise whitebarks that are resistant to the beetles. But Mahalovich is still optimistic. "We can restore the whitebark," she says.