Official Status:

Life History:

Whitebark pine is a 5-needled conifer species placed in the subgenus Strobus , which also includes other 5-needled white pines. Whitebark pine is a stone pine (so-called for their stone-like seeds). Only five species of stone pines are recognized worldwide, and whitebark pine is the only stone pine that occurs in North America. Characteristics of stone pines include five pine needles per cluster, cones that stay on the tree, and wingless seeds that remain fixed to the cone and cannot be dislodged by the wind. Because whitebark pine seeds cannot be wind-disseminated, primary seed dispersal occurs almost exclusively by Clark's nutcrackers ( Nucifraga columbiana ) in the avian family Corvidae (whose members include ravens, crows, and jays). This pine is a very long-lived species with some individuals documented at over 1,000 years old.

Whitebark pine is considered a keystone species in high elevation ecosystems because it increases biodiversity and contributes to critical ecosystem functions. It is frequently the first conifer to become established after disturbances like wildfires and subsequently stabilizes soils and regulates runoff. Snow will drift around whitebark pine trees, thereby increasing soil moisture, modifying soil temperatures, and holding soil moisture later into the season. Whitebark pine also provides important, highly nutritious seeds for numerous birds and mammals. In addition to these important contributions to high elevation ecosystems, whitebark pine forests have a high esthetic value that is prized by backcountry hikers and other recreational users.

Distribution and Habitat:

Roughly 44 percent of the species' range occurs in the United States in Wyoming, Montana, Idaho, Nevada, California, Oregon, and Washington. The remaining 56 percent of the species range occurs in British Columbia and Alberta, Canada. It typically occurs on cold and windy high-elevation or high-latitude sites.

Threats:

Threats to the whitebark pine include habitat loss and mortality from white pine blister rust, mountain pine beetle, catastrophic fire and fire suppression, environmental effects resulting from climate change, and the inadequacy of existing regulatory mechanisms. Whitebark pine is experiencing an overall long-term pattern of decline, even in areas originally thought to be mostly immune from the above threats. Recent predictions indicate a continuing downward trend within the majority of its range. While individual trees may persist, given current trends the Service anticipates whitebark pine forests will likely become extirpated and their ecosystem functions will be lost in the foreseeable future. On a landscape scale, the species appears to be in danger of extinction, potentially within as few as two to three generations. The generation time of whitebark pine is approximately 60 years.

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