Natural Resources
Conservation Service
Ecological site R022AX006CA
High Gradient, Glacially Scoured Headwater Riverine
Accessed: 05/19/2026
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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
Major Land Resource Area (MLRA) 22A, Sierra Nevada Mountains, is found primarily in California, and to a minor extent in Nevada. It lies entirely within the Sierra Nevada Mountains. Most of this area is dominated by granitic bedrock from the Sierra Nevada Batholith. It is characterized by hilly to steep mountain relief and occasional mountain valleys. The average annual precipitation is 40 to 80 inches (1,015 to 2,030 millimeters) in much of this area, but it as low as 6 inches (150 millimeters) in the lower elevations and as much as 100 inches (2,540 millimeters) on the mountain peaks. Much of the winter precipitation occurs as snow. The average annual temperature is 25 to 63 degrees F (-4 to 17 degrees C), decreasing with elevation. The freeze-free period ranges from 65 to 345 days, decreasing in length with elevation. Elevation ranges from 1,500 to 9,000 feet (455 to 2,745 meters) in most of the area. The highest peaks can exceed 12,000 feet (3,660 meters). Mount Whitney, at an elevation of 14,494 feet (4,419 meters), is the highest point in the lower 48 States. The soils in the area dominantly have a mesic, frigid, or cryic soil temperature depending largely on elevation; a xeric soil moisture regime; and mixed mineralogy. This area supports montane coniferous forests, dominated by Ponderosa pine at the lower elevations, white fir forest type in the mid elevations, California red fir or Jeffrey pine forest types at the upper montane region, and mountain hemlock, Sierra lodgepole pine, and whitebark pine forest types in the subalpine zone. At the highest elevations are alpine plant communities, and montane shrublands. Meadows and riparian systems are present throughout the MLRA. Chaparral communities are present at the lowest elevations. 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 “AX” Ubiquitous in MLRA (environmental or chemical features dominate).
This LRU designation is set aside for ecological sites that are ubiquitous throughout the MLRA. These sites are driven by environmental or chemical features that override the climatic designations of the other LRU's or are atypical compared to the surrounding landscape. The “AX” LRU in this MLRA is composed primarily of riparian areas, meadows, and seeps. Riparian ecological site complexes are influenced or formed by water. Soils may have redoximorphic features, finer textures than the upland soils, multiple depositional layers, and/ or organic surface horizons. These sites are associated with meadows, stream channels, seeps, discharge slopes, or depressions.
Ecological site concept
This site is comprised of a riparian high (mid) gradient stream system. These are small headwater and first order streams located in alpine and subalpine glacial cirques and basins. Elevations are between 10,800 and 12,000 feet (3291 to 3658 m). Channel gradient ranges from 3 to 15%. Channel morphology changes quickly as it cascades over bedrock benches, into flatter meadows, and across cobbly till. Several community components are present. Along the more active channels is a Sierra willow (Salix orestera) - scented shootingstar (Dodecatheon redolens) community. On more stable floodplains and benches a community composed of dwarf bilberry (Vaccinium cepsitosum), alpine willow (Salix petrophila), purple mountainheath (Phyllodoce breweri), shorthair reedgrass (Calamagrostis breweri), and Idaho bentgrass (Agrostis idahoensis) is present. A diversity of species may be present. This ecological site may be associated with R022AX007CA when stream gradients are below 2% and may be associated with R022AX002CA when stream gradients are greater than 20 percent.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Salix orestera
Herbaceous (1) Dodecatheon redolens