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The Challis Field Office encompasses an area dominated by two varieties of long-lived five-needled trees: limber pine (Pinus flexilus) and whitebark pine (Pinus albicaulis). Both can survive in harsh environments, are drought resistant and produce high-fat, energy-rich and nut-like seeds that provide diet for a variety of creatures including red squirrels, Clark’s nutcrackers and American black bears. Seeds develop in cones that are harvested and dispersed by Clark’s nutcracker. These trees also offer nesting habitat for Northern flickers, Mountain bluebirds and squirrels. Both may occur with high elevation Douglas-Fir on dry sites, as well as with mountain mahogany.
Limber pine is more common than whitebark pine and generally occurs at elevations from approximately 5,500 feet to treeline. It is more common on the eastern areas of the Field Office. Whitebark pine may occur at slightly higher elevations, and is found more commonly in the western regions of the Challis area. Whitebark pine is also recognized as a keystone species of high elevation habitats and is vital in maintaining a healthy ecosystem. Although they appear similar at first glance, upon closer observation they can be distinguished by specific characteristics of their cones. The whitebark pine cone is indehiscent, which means that its cone scales do not open freely upon maturity and drying. The seeds within the cones are not dropped out or scattered by the wind. Whitebark pine seeds are dependant upon the Clark’s nutcracker for seed dispersal. When the Clark's nutcracker fails to retrieve the cached seed, the seed may germinate and become a tree. It is rare to find an intact whitebark pine cone because Clark’s nutcrackers and red squirrels harvest them quickly and efficiently when they are available. The fragile cones from a whitebark pine are 4-7 cm long and are dark purple when immature.
For more information please visit: http://www.whitebarkfound.org/ or USGS webpages:
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The BLM has been working to protect ancient stands of whitebark pine, which surpass 400 years of age, in the Poverty Flat Area. Poverty Flat is located at 9,400 feet near the confluence of the East Fork and Main Salmon Rivers. Whitebark populations are being reduced by a variety of factors including blister rust from Europe, fire suppression and mountain pine beetle. In response to this deadly epidemic, the Challis Field Office initiated a project in early summer 2005 to treat 500 whitebark pines with a capsulated repellant, Verbenone, to provide individual trees protection from mountain pine beetles. The project will continue, pending funding, to fight these dangerous invaders.
Limber Pine is not indehiscent, so the cone scales open and the seeds and cones fall to the ground. Since the seed can free-fall, it may find a microsite to germinate and become a tree. Whole cones are likely found underneath this tree, as opposed to the whitebark pine cones. Cones from a limber pine are 6-12 cm long, light green or tan when immature.