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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
MLRA 22A
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 has s 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 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. 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 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 "B" Southern Sierra Subalpine
The Southern Sierra sublalpine LRU "B" occurs south of latitude 39 degrees north, and elevations are typically between 9,000 to 10,500 feet (2,743 to 3,200 m). MAAT ranges from 31 to 40 degrees F (-0.5 to 4.4 C), MAP ranges from 32 to 59 inches (813 to 1,499 mm), and the frost free season is 25 to 60 days. Forests are dominated by whitebark pine and foxtail pine near timberline, and a mix of Sierra lodgepole pine, whitebark pine, and/or mountain hemlock at the lower elevations. Threadleaf sedge (Carex filifolia) or mountain heather dominates the non-forested areas.Ecological site concept
This ecological site is typically on lower 1/3 of north facing slopes with very deep soils in concave positions with additional moisture. Soils have a high percentage of rock fragments (skeletal), with sandy loam or very fine sandy loam textures. Sierra lodgepole pine (Pinus contorta var. murrayana) is dominant in the overstory and purple mountain heath (Phyllodoce breweri) is abundant in the understory. Whitebark (Pinus albicaulis) pine may be present at the higher elevations.
Table 1. Dominant plant species
Tree (1) Pinus contorta ssp. murrayana
(2) Pinus albicaulisShrub (1) Phyllodoce breweri
Herbaceous Not specified