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State Plans Idaho
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Central Rocky Mountains
(Area - 60,227,400 ha)
Description - The Central Rockies is a huge physiographic
area, extending from northwest Wyoming over all of western Montana, the northern 2/3 of
Idaho, large areas of eastern Oregon and Washington, much of southeast British Columbia
and a sliver of west Alberta. It is an area of high mountains, with elevations up to 2,700
m (9,000 ft). Glaciation has left broad flat valleys between mountain ranges. Elevation
determines the dominant vegetation. Highest areas are alpine tundra. The subalpine zone is
dominated by Engelmann spruce and subalpine fir, with ponderosa pine and Douglas fir in
the montane zone below that. Stand-replacement fire can change forests in either of those
zones to lodgepole pine or aspen. Grass and sagebrush occur under open pine forests that
grade downslope into grasslands, woodlands, or shrubsteppe.
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Conservation recommendations and needs - Approximately 28 species of birds have a larger population in the Central Rocky Mountains than in any other physiographic area. This is the largest such number of any physiographic area in the lower 48 states. It seems to represent the huge size of the area and the vast quantity of quality bird habitat that still exists. This is not an area of noted endemism, but is the heart of the mountainous West and the center of distribution for many birds, particularly those of coniferous forests, that range more widely.
Perhaps the habitat that has been most altered in this region is that dominated by ponderosa pine. These forests were adapted to frequent low-intensity fires, and as a result presented a parkland aspect dominated by very large trees primarily of this single species. Birds particularly adapted to this system include the White-headed Woodpecker and Flammulated Owl. Harvest of the larger trees and fire suppression have created opportunities for invasion and co-dominance by Douglas fir and other trees, radically changing the nature of the forest. Where the other trees have matured, restoration involved mechanical harvest of unwanted trees followed by regular fire management. The Forest Service has ambitious plans, supported by PIF, for restoration of ponderosa pine ecosystems on its lands.
Unlike historical fire in ponderosa pine, fire in higher elevation forest tends to be of high intensity and low frequency. After such stand-replacing fires, either aspen or lodgepole pine occupy a site until a century or more of succession results in redominance of the site-specific hemlock, spruce, or fir species. Many birds track this process. Both Black-backed and Three-toed Woodpeckers specialize in foraging on charred post-fire trees. Blue Grouse and Williamson’s Sapsucker are among those species most abundant in aspen.
A huge percentage of the Central Rockies in the United States is in public ownership, mostly by the Forest Service. Maintenance or restoration of healthy forest ecosystems on public and private industrial lands will be the most important factor in keeping the Central Rocky Mountains a source for so many forest birds.
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