Level IV: (80k) Partly Forested Mountains
The Partly Forested Mountains ecoregion occupies the elevational belt above the Semiarid Uplands on the Jarbidge, Independence, Owyhee, and Steens mountains, from 6,500 to 10,900 feet (1,981 to 3,322 m). These are partially glaciated, high, rugged mountains with glacial features including moraines, cirques, and tarn (lake)s.
Perennial or intermittent, high gradient, cold streams are fed by snowmelt and springs, supporting federally threatened bull trout and Lahontan cutthroat trout in Nevada. Riffle segments have cobble or boulder substrates.
Annual precipitation is sufficient to support a Great Basin pine forest community of Douglas-fir, subalpine fir, ponderosa pine, and limber pine, with whitebark pine near the tree line, and aspen stands in riparian meadows, moist draws, and wet depressions. The understory features low juniper, mountain big sagebrush, mountain brush, serviceberry, snowberry, mountain-mahogany, Idaho fescue, sheep fescue, rough fescue, bottlebrush squirreltail, prairie lupine, mountain brome, bluebunch wheatgrass, and Sandberg bluegrass. Small areas of tundra and alpine meadows are found at the highest elevations. On Steens Mountain, above the juniper woodland zone of the Semirarid Uplands, the landscape is almost treeless; broad areas of mountain big sagebrush alternate with scattered groves of aspen.
Alpine areas on Steens Mountain were seriously eroded following intense grazing by domestic sheep in the late 19th century. The region covers 105 square miles (272 km2) in Nevada, 103 square miles (267 km2) in Oregon, and 38 square miles (98 km2) in Idaho, and contains the Jarbidge Wilderness in the Humboldt-Toiyabe National Forest.