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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 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 22AG Central (northern) Mid Montane Sierran Montains
This LRU occurs between the elevations of 3,600 to 5,900 ft (1097 to 1798 m), and extends from the Tuolumne River in the south to highway 80 in the north . The MAAT ranges from 48 to 52 degrees F (8.9 to 11.1 degrees C), MAP ranges from 41 to 63 inches (104 to 160 cm), and the frost free season ranges from 115 to 180 days. Geology is primarily granitic (Cretaceous granodiorite and quartz monzonite), with areas of Tertiary andesite and ryholite. Ponderosa pine (Pinus ponderosa) forests are dominant, and increase on south facing slopes at the lower elevations and southern latitudes. Incense cedar (Calocedrus decurrens) and sugar pine (Pinus lambertiana) are intermixed in the ponderosa pine forests. Douglas-fir (Pseudotsuga menziesii) forests are restricted to moist north facing slopes. White fir (Abies concolor) occurs at the highest elevations.Ecological site concept
This ecological site occurs on the more moist landscape positions (i.e. N-facing) found at elevations of 1000 - 1500 m on steep slopes (> 50%, usually N facing) and deep cut drainages. Generally exceed 45 inches of MAP.
Dense stands of Douglas fir are common. As these are steep and often do not receive much solar radiation, the productivity is lower than other AG sites (F022AG202CA), but generally greater than the AI sites.Table 1. Dominant plant species
Tree (1) Pseudotsuga menziesii
(2) Pinus ponderosaShrub (1) Chamaebatia foliolosa
(2) Ribes nevadenseHerbaceous Not specified