Natural Resources
Conservation Service
Ecological site F022AC004CA
Cryic Very Gravelly Loamy Mountain Slopes
Accessed: 11/02/2024
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
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 = Abies magnifica-Abies concolor – Red fir-white fir forest; Association = tentatively Abies magnifica-Abies concolor-Pinus jeffreyi. (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 is found on gentle to steep upper montane mountain slopes at elevations of approximately 7,500 to 9,000 feet, predominately along the eastern side of the Lake Tahoe Basin, where precipitation is relatively lower. Slopes are typically between 30 and 50 percent. Soils are very deep, and are derived from metamorphic parent material. Soils have a high degree of development, with argillic horizons and loam and silty clay loam subsurface textures. The vegetation is a relatively open California red fir (Abies magnifica) - Jeffrey pine (Pinus jeffreyi) forest with a dense understory of upper montane shrubs, which commonly includes roundleaf snowberry (Symphoricarpos rotundifolius) and wax currant (Ribes cereum). California red fir is a slow-growing, long-lived tree that has high frost tolerance and low drought tolerance, and reaches dominance only in cooler and moister upper elevation. Jeffrey pine is indicative of the eastern, lower precipitation environment of this site. Loamy soils support the dense understory.
Associated sites
F022AC003CA |
Frigid-Cryic Sandy Slopes Occurs on adjacent mountain slopes with moderately deep to very deep, poorly developed, gravelly coarse sandy soils over decomposed granite. Vegetation is a red fir (Abies magnifica) - western white pine (Pinus monticola) forest with pinemat mananita (Arctostaphylos nevadensis) dominant in canopy openings. |
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F022AF006CA |
Loamy Frigid Metamorphic Slopes Occurs on lower elevation slopes with very deep, fine loamy soils developed from metamorphic parent material. The forest is dominated by a dense productive Jeffrey pine (Pinus jeffreyi) and white fir (Abies magnifica) forest, and a diverse herbaceous understory is present. |
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. |
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
F022AC008CA |
Cryic Volcanic Mountain Slopes This site is found on south-facing slopes in areas receiving more precipitation. White fir (Abies concolor) is co-dominant with red fir (Abies magnifica). Greenleaf manzanita (Arctostaphylos patula) and whitethorn ceanothus (Ceanothus cordulatus) are common shrub species. |
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F022AC003CA |
Frigid-Cryic Sandy Slopes This site occurs on poorly developed soils derived from granitic parent materials. Western white pine (Pinus monticola) is co-dominant with red fir (Abies magnifica) and Jeffrey pine (Pinus jeffreyi) is a minor species if present. The understory is less productive and less diverse, and is dominated by pinemat manzanita (Arctostaphylos nevadensis). |
F022AF006CA |
Loamy Frigid Metamorphic Slopes This site is found at lower elevations. White fir (Abies concolor) is co-dominant with Jeffrey pine (Pinus jeffreyi), while red fir (Abies magnifica) is a secondary species. |
F022AE007CA |
Frigid, Sandy, Moraines And Hill Slopes This site occurs on lower elevations on glacial outwash and moraines. White fir (Abies concolor) is co-dominant with Jeffrey pine (Pinus jeffreyi), and red fir (Abies magnifica) is a minor species if present. |
F022AF004CA |
Frigid, Shallow To Deep, Sandy Mountain Slopes This site occurs at on south-facing slopes at lower elevations on poorly developed sandy soils. The vegetation is dominated by an open Jeffrey pine (Pinus jeffreyi) forest while red fir (Abies magnifica) is a minor species if present. A dense shrub layer has variable composition, with greenleaf manzanita (Arctostaphylos patula) and antelope bitterbrush (Purshia tridentata) common species. |
F022AF005CA |
Frigid, Deep To Very Deep, Sandy-Loamy Mountain Slopes This site is found at lower elevations on north-facing slopes with coarse sandy soils. White fir (Abies concolor) is co-dominant with Jeffrey pine (Pinus jeffreyi) and red fir (Abies magnifica) is minor if present. |
Table 1. Dominant plant species
Tree |
(1) Abies magnifica |
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Shrub |
(1) Symphoricarpos rotundifolius |
Herbaceous |
(1) Lupinus argenteus |
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