Natural Resources
Conservation Service
Ecological site F022AC007CA
North-Facing Cryic Loamy Mountain Slopes
Accessed: 12/05/2024
General information
Approved. An approved ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model, enough information to identify the ecological site, and full documentation for all ecosystem states contained in the state and transition model.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
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 a 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, arêtes, 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 "C" Northern Sierra Subalpine: Elevations are typically between 7,800 and 9,800 feet. The frost free period is between 30 and 90 days, MAAT is between 35 and 44 degrees, MAP is between 45 and 65 inches. Soils are typically cryic, but frigid soils may occur at lower elevations on southern aspects. Forests are dominated by whitebark pine (Pinus albicaulis), Sierra lodgepole pine (Pinus contorta spp. murrayana), mountain hemlock (Tsuga mertensiana) and/or California red fir (Abies magnifica).
Classification relationships
Forest Alliance = Tsuga mertensiana – Mountain hemlock forest; Association =tentatively Tsuga mertensiana-Pinus contorta ssp. murrayana-Pinus monticola. (Sawyer, John O., Keeler-Wolf, Todd, and Evens, Julie M. 2009. A Manual of California Vegetation. 2nd ed. California Native Plant Society Press. Sacramento, California.)
Ecological site concept
This site occurs on moderate to steep subalpine, north-facing mountain slopes typically between 7,600 and 9,000 feet. Slopes are typically between 15 and 70 percent. At these high elevations snow persists late into the season, and the growing season is short. Soils are andic, and are moderately deep over paralithic andesitic tuff with medial skeletal textures. Fertile loamy soils support a relatively productive subalpine forest dominated by mountain hemlock (Tsuga mertensiana), western white pine (Pinus monticola), Sierra lodgepole pine (Pinus contorta var. murrayana) and California red fir (Abies magnifica). The understory is generally sparse with scattered grasses and forbs.
Associated sites
F022AC006CA |
Moderately Deep Cryic Sandy Till Occurs on adjacent south-facing slopes with moderately deep, loamy-skeletal soils over dense till, derived primarily from volcanic parent material. Vegetation is an open Sierra lodgepole pine forest (Pinus contorta var. murrayana) with red fir (Abies magnifica) and western white pine (Pinus monticola). |
---|---|
F022AX101CA |
Moist Colluvial Headwater System Occurs on adjacent headwater swales and first order streams. A complex of vegetation community types is present, and quaking aspen (Populus tremuloides) is a characteristic species. |
R022AA200CA |
Alpine Scree Occurs at higher elevations, above treeline, on windswept alpine slopes and ridges with very shallow to moderately deep, sandy skeletal granitic soils. The sparse vegetation consists of dwarf forbs and grasses. |
R022AC202CA |
Shallow Andesite Ridge Occurs on adjacent slopes with loamy shallow soils over andesitic bedrock. The vegetation is a low productivity shrubland dominated by low sagebrush (Artemisia arbuscula). |
R022AC204CA |
Cryic, Umbric Or Andic Slopes Occurs on adjacent mountain slopes with andic soils or a thick umbric epipedon. Mountain big sagebrush (Artemisia tridentata ssp. vaseyana) and antelope bitterbrush (Purshia tridentata) dominate with a productive herbaceous community. |
Similar sites
F022AC005CA |
Cryic Sheltered, Moist Sandy Mountain Slopes This site occurs on deep sandy skeletal granitic soils. The overstory vegetation is similar, but the understory is generally more productive and dense, with purple mountainheath (Phyllodoce breweri) and rose meadowsweet (Spiraea splendens) frequently dominant in the understory. |
---|---|
F022AC002CA |
Cryic Sandy North Apsect Mountain Slopes This site occurs in more exposed positions at higher elevations near treeline. Mountain hemlock (Tsuga mertensiana) dominates with whitebark pine (Pinus albicaulis), and there is very little understory vegetation. |
Table 1. Dominant plant species
Tree |
(1) Tsuga mertensiana |
---|---|
Shrub |
Not specified |
Herbaceous |
(1) Eucephalus breweri |
Click on box and path labels to scroll to the respective text.