Natural Resources
Conservation Service
Ecological site F022AY121NV
Pinus contorta-Abies magnifica/Artemisia tridentata ssp. tridentata/Achnatherum occidentale ssp. occidentale-Carex rossii
Accessed: 09/08/2026
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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Table 1. Dominant plant species
Tree (1) Pinus contorta
(2) Abies magnificaShrub (1) Artemisia tridentata ssp. tridentata
Herbaceous (1) Achnatherum occidentale ssp. occidentale
(2) Carex rossiiPhysiographic features
This forest community typically occurs on high elevations mountains on middle to upper sideslopes and ridge tops. This site occurs on all aspects but is most common on southeast and southwest-facing slopes. These sites characteristically lie above 8,000 feet. Slopes range from 15 to 75 percent, but 15 to 30 are most typical.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 8000 – 10000 ft Slope 15 – 75 % Aspect SE, SW Climatic features
">Influencing water features
There are no influencing water features associated with this site.
Soil features
Table 3. Representative soil features
Surface texture (1) Very gravelly loamy coarse sand
(2) Very bouldery coarse sand
(3) Very bouldery loamy coarse sand
Family particle size (1) Sandy
Drainage class Excessively drained Permeability class Rapid Soil depth 8 – 20 in Surface fragment cover <=3" 25 – 30 % Surface fragment cover >3" 15 – 35 % Available water capacity
(0-40in)0.7 – 0.9 in Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)4.5 – 6.5 Subsurface fragment volume <=3"
(Depth not specified)16 – 23 % Subsurface fragment volume >3"
(Depth not specified)2 – 26 % Ecological dynamics
This site is dominated by lodgepole pine and red fir. Sierra lodgepole pine establishes soon after disturbance and is moderatley shade tolerant. It forms stable climax communities in the zone just above red fir and white fir-mountain hemlock forests. California red fir will eventually become the climax species under a closed canopy of lodgepole pine. California red fir establishes well in openings and after disturbances and is moderately shade tolerant.
Fire Ecology:
Fire has an important role in Sierra Nevada conifer forests,particularly in the successional relationship between California red fir and lodgepole pine. Fire creates canopy openings by killing mature lodgepole pine and some mature California red fir. Where lodgepole pine occurs under a California red fir canopy, it is eventually succeeded by California red fir. The estimated fire frequency ranges from 10 to 65 years.
Seedlings of California red fir are easily killed by fire. Seedlings and saplings are killed by relatively low-intensity fires, but few older California red fir are affected. Larger California red fir are killed by severe fires.
Fire-return intervals in Sierra lodgepole pine forests vary. On the eastern slope where
drier conditions prevail, such fires may occur at intervals of less than 20 years. Sierra lodgepole pine is usually killed by fire because of its shallow root system and thin bark. Stand-replacing fires are related to insect attacks, particulary by pine mountain beetle, and declining vigor and high fuel loading in older stands. When fires occur in Sierra lodgepole stands, they are usually intense and extensive.
Mountain big sagebrush is highly susceptible to injury from fire. Plants are readily killed in all seasons, even light severity fires. Mountain big sagebrush plants top-killed by fire will not resprout.State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe historic climax plant community is the interpretative plant community for this site. The historic climax plant community is characterized by and overstory canopy of 10 to 25 percent. This site is dominated by lodgepole pine and California red fir. Western white pine, Jeffrey pine and Sierra juniper may also occur in the overstory. Shrubs are sparse in the understory of this site. Ross' sedge and western needlegrass are the most prevalent grass and grass-like species. Rockcress, coyote mint, phlox, and buckwheat are the most common uderstory forbs.
Forest overstory.Overstory tree composition is about 40 to 60 percent lodgepole pine with 25 to 40 percent California red fir and 5 percent each of Sierra juniper, Jeffrey pine, and western white pine.<br /> <br /> Major Successional Stages of Woodland Development<br /> <br /> HERBACEOUS: Vegetation is dominated by grasses and forbs under full sunlight. This stage is experienced for a short period after major disturbance such as crown fire or tree harvest. Skeleton forest (dead trees) remaining after fire or residual trees left following harvest have little or no affect on the composition and production of the herbaceous vegetation.<br /> <br /> SHRUB-HERBACEOUS: Herbaceous vegetation and woody shrubs dominate the site. This stage is experienced within two to three years after fire or harvest. Various amounts of tree seedlings (less than 20 inches in height) may be present up to the point where they are obviously a major component of the vegetal structure.<br /> <br /> SAPLING: In the absence of disturbance the tree seedlings develop into saplings (20 inches to 4.5 feet in height) with a range in canopy cover of about 5 to 10 percent. Vegetation consists of grasses, forbs and shrubs in association with tree saplings. Understory shrubs dominate the plant community.<br /> <br /> IMMATURE WOODLAND: The visual aspect and vegetal structure are dominated by lodgepole pine greater than 4.5 feet in height. At this stage of woodland development, the tree canopy has successfully broken through the suppression of early successional shrub communities. The young trees are still very susceptible to fire at this stage. The upper crown of dominant and co-dominant lodgepole pine are cone or pyramidal shaped. Seedlings and saplings of pines are common in the understory. Red fir saplings are common in the understory. Dominants are the tallest trees on the site; co-dominants are 65 to 85 percent of the highest of dominant trees. Understory vegetation is moderately influenced by a tree overstory canopy of about 10 to 20 percent.<br /> <br /> MATURE WOODLAND: The visual aspect and vegetal structure are dominated by lodgepole pine and red fir that have reached or are near maximal heights for the site. Tree canopy cover ranges from 10 to about 25 percent. This stage of community development is assumed to be representative of this woodland site in the pristine environment.<br /> <br /> OVER-MATURE WOODLAND: This stage is dominated by red fir and lodgepole pine that have reached maximal heights for the site. Tree canopy cover is commonly greater than 45 percent.<br /> <br />
Forest understory. Understory vegetative composition is about 45 percent grasses, 45 percent forbs, and 10 percent shrubs and young trees when the average overstory canopy is medium. verage understory production ranges from 80 to 180 pounds per acre.
Additional community tables
Table 4. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Livestock Interpretations:
This site is poorly suited to livestock grazing due to low forage production. When livestock use occurs, it is primarily the result of grazing animals transiting this site to access more productive cummunities.
Initial Stocking Rates
Stocking rates vary with such factors as kind and class of grazing animal, season of use and fluctuations in climate. Actual use records for individual sites, a determination of the degree to which the sites have been grazed and an evaluation of trend in site condition offer the most reliable basis for developing initial stocking rates.
Selection of initial stocking rates for given grazing units is a planning decision. This decision should be made only after careful consideration of the total resources available, evaluation of alternatives for use and treatment and establishment of objectives by the decision maker.
Example: Sample Calculations using Favorable Year production amounts:
500 lbs of available forage/ac x. 25 (Harvest Efficiency) = 125 lbs forage consumed
125 lbs/790 lbs = .16 AUMs/ac or 6.32 ac/AUM
NOTE: 790 lbs/month for one Animal Unit is used as the baseline for maintenance requirements. This equates to 30 lbs/day of air-dry forage (1000 lb cow at 2.6% of body weight). See NRCS National Range and Pasture Handbook.
Forage Value Rating
The forage value rating is not an ecological evaluation of the understory as is the range condition rating for rangeland. The forage value rating is a utilitarian rating of the existing understory plants for use by specific kinds of grazing animals.
Wildlife Interpretations:
This forest site provides food and shelter for squirrels, birds, deer, bear, bobcats, and mountain lions. Dead or dying trees provide nesting site for cavity-nesting birds and mammals. The fallen branches from these trees provide ground nesting birds and mammals. Blue grouse feed on Sierra lodgepole pine needles during the winter. The seeds are a food source for squirrels, chipmunks, birds, and mice.Hydrological functions
The hydrology of this site is characterized by heavy snowmelt in the spring, with very little precipitation in the summer months.
Recreational uses
This area would be available for hiking throughout, and biking and cross/country skiing on available dirt roads.
Wood products
Lodgepole pine and red fir provide timber products. Thinning projects would increase the health of the forest, reduce extreme fire hazards, and maintain the natural dominance of the lodgepole pine and red fir forest.
PRODUCTIVE CAPACITY
Low quality site for tree production. Site index for lodgepole pine ranges from about 60 to 75. (Table 25, SCS, 190-V-NFM Amend.3; from Dahms, 1964. USDA FS PNW Res. Paper No.8).
Site index for red fir ranges from about ?? to ??. (Table 23, SCS, 190-V-NFM Amend.3; from Schumacher, 1928. Calif. Ag. Exp. Sta. Bull. No. 456).
Productivity Class (Lodgepole Pine): 4
Productivity Class (Red Fir): 7
CMAI* (Lodgepole Pine): <51 to 64 cu ft/ac/yr;<3.6 to 4.5 cu m/ha/yr.
*CMAI: is the culmination of mean annual increment highest average growth rate of the stand in the units specified.
Basal Area (Lodgepole Pine): 119 sq. ft./acre with average D.B.H=15" and average age 126years (AB50).
Other products
California red fir are used for christmas trees. Cones can be used for decorations and art projects.
Native peoples used big sagebrush leaves and branches for medicinal teas, and the leaves as a fumigant. Bark was woven into mats, bags and clothing.Table 5. Representative site productivity
Common name Symbol Site index low Site index high CMAI low CMAI high Age of CMAI Site index curve code Site index curve basis Citation lodgepole pine PICO 62 75 51 64 – – – Supporting information
Type locality
Location 1: Mono County, CA Latitude 38° 49′ 15″ Longitude 119° 54′ 29″ General legal description Toiyabe National Forest. Other references
Fire Effects Information System[Online], http://www.fs.fed.us/database/feis
Plants Database [Online], http://www.plants.usda.gov
Lanner, Ronald M.. 1984. Trees of the Great Basin, A Natural History. Reno University of Nevada Press.
Dahms, W. G.. 1964. Data from Grass and Net Yield Tables for Lodgepole Pine. USDA FS PNW No. 8.
USDA-NRCS. 1980. National Forestry Manual - Part 537. Washington, D.C.
Potter, D. A. 1998. Forested Communities of the Upper Montane in the Central and Southern Sierra Nevada. USDA FA PSW GTR 169.
Schumacher, F. X. 1928. Normal Yeld Tables for Red Fir. Calif. Ag. Exp. Sta. Bull. No. 456).
Contributors
Angela Mushrush
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
Author(s)/participant(s) Contact for lead author Date Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
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Perennial plant reproductive capability:
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