John Muir Wilderness

Occupying much of the Sierra between Yosemite and Sequoia-Kings Canyon National Parks, the John Muir Wilderness is the largest in the State. On the west, the Wilderness begins in the mid-elevations and extends eastward to include portions of the Sierra crest and the eastern escarpment. Thus there is a variety of communities present, ranging from the ponderosa pine forest on the lower slopes in the west to alpine fell fields near the crest.

In the lower portions a mixed conifer forest occurs, with white fir, Abies concolor, Jeffrey, ponderosa and sugar pines, Pinus jeffreyi, Pinus ponderosa and Pinus lambertiana. Higher, there is a red fir forest with Abies magnifica and lodgepole and silver pines, Pinus murrayana and Pinus monticola, which, in turn, gives way to a subalpine forest with whitebark pine, Pinus albicaulis, limber pine, Pinus flexilis, foxtail pine, Pinus balfouriana, and mountain hemlock, Tsuga mertensiana.

Alpine and subalpine meadows are present, as are several riparian associations. Quaking aspen, Populus tremuloides, occurs in the moist areas, as does the water birch, Betula occidentalis, on the eastern slope. In the higher elevations much of the area is barren or with very sparse, scattered vegetation.

Nine rare or uncommon plants have been found in the area: Aster peirsonii, Astragalus ravenii, Dicentra nevadensis, Draba lonchocarpa var. lonchocarpa, Hackelia sharsmithii, Ivesia argyrocoma, Lomatium rigidum, Lupinus padre-crowleyi and Penstemon papillatus.

Animal life is abundant. An estimated 50,000 head of mule deer, Odocoileus hemionus, utilize the area during the summer. Several bands of bighorn sheep, Ovis canadensis, range the Wilderness. Among other mammals found here are pika, Ochotona princeps, marmot, Marmota flaviventris, marten, Martes americana, fisher, Cartes pennanti, and the rare wolverine, Gulo luscus. Birds include such montane and alpine inhabitants as Clark's nutcracker, Nucifraga columbiana, and gray-crowned rosy finch, Leucosticte tephrocotis.

Mesozoic granitic rocks of the Sierra batholith, which are exposed and form rock barrens in much of the higher part of the area, underlie most of the Wilderness. Other formations include Paleozoic limestones and, on the eastern boundary, Pleistocene lava flows.

Approximately 20 glaciers occur in the Wilderness between the Mount Abbott region in the north and the Palisades in the south. The Palisade glacier is the largest existing glacier in the Sierra and is approximately 2.4 kilometers (1.5 miles) long; it is, however, about half the size it was in 1850. The middle Palisade glacier, a kilometer or so southeasterly, is the southernmost glacier in the United States.

Moraines, cirques, tills and other evidence of glacial activity are common in the area.

Integrity: There are trails and other facilities within the boundaries. Portions are heavily impacted by human and pack-animal use, and protective measures have been undertaken and are under further consideration .

Use: Present

March 1980