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Major Land Resource Area or ecological site by name and/or ID.
General information
Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
MLRA notes
Major Land Resource Area (MLRA): 022A–Sierra Nevada and Tehachapi Mountains
Major Land Resource Area 22A, Sierra Nevada Mountains, is located predominantly in California and a small section of western Nevada. The area lies completely within the Sierra Nevada Section of the Cascade-Sierra Mountains Province. The Sierra Nevada range is highly asymmetrical with a long, gentle western slope, and a very abrupt eastern slope. The Sierra Nevada consists of hilly to steep mountains and occasional flatter mountain valleys. Elevation ranges between 1,500 and 9,000 ft throughout most of the range, but certain peaks often exceed 12,000 ft. The highest point in the continental US occurs in this MLRA (Mount Whitney, 14,494 ft). Most of the Sierra Nevada is dominated by granitic rock of the Mesozoic age, known as the Sierra Nevada Batholith. The northern half is flanked on the west by a metamorphic belt, which consists of highly metamorphosed sedimentary and volcanic rocks of Paleozoic and Mesozoic ages. Additionally, glacial activity of the Pleistocene has played a major role in shaping Sierra Nevada features, including cirques, arĂȘtes, and glacial deposits and moraines. Average annual precipitation ranges from 20 to 80 inches in most of the area, with increases along elevational and south-north gradients. Soil temperature regime ranges from mesic, frigid, and cryic. Due to the extreme elevational range found within this MLRA, Land Resource Units (LRUs) were designated to group the MLRA into similar land units.
LRU "H" Southern Sierra Mid Montane
This LRU comprises the mid-elevations (4,218 to 7,000 ft) of the western slope of the southern Sierra Nevada. The frost free season is 85 to 165 days, MAAT ranges from 43 to 52 degrees F, and MAP ranges from 18 to 47 inches . Soil temperature regimes are mesic and frigid, while soil moisture regimes are xeric. Geology is primarily granitic, with some metamorphic rock. This LRU contains most of the giant sequoia (Sequoiadendron giganteum) groves in the Sierra Nevada.Ecological site concept
This ecological site occurs on upland areas on colluvium, alluvium and/or till in canyon bottoms, often associated with C-channel systems. Slope is generally low 2-15%. Site has a mesic soil temperature regime with deep to very deep sandy-skeletal soils. Sites range from dense incense cedar to ponderosa pine, and variable understories.
Table 1. Dominant plant species
Tree (1) Pinus ponderosa
(2) Calocedrus decurrensShrub Not specified
Herbaceous (1) Poa cusickii
(2) Achnatherum