Natural Resources
Conservation Service
Ecological site R010XC070OR
SR Mountain
16-20 PZ
Last updated: 4/10/2025
Accessed: 06/28/2026
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Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Associated sites
R010XC032OR SR Mountain 12-16 PZ
SR Mountain 12-16 PZ - Lower elevation, ppt. and different composition - greater diversity of species
R010XC037OR SR Mountain Shallow 12-16 PZ
SR Mountain Shallow 12-16 PZ - Stony Loam surface texture, shallow to bedrock, lower production
R010XC040OR SR Very Shallow 16-20 PZ
SR Very Shallow 16-20 PZ - Very shallow to bedrock, lower production, dominated by stiff sagebrush and Sandberg bluegrass
R010XC049OR SR Shrubby Mountain South 16-20 PZ
SR Shrubby Mountain South 16-20 PZ - Steeper south aspects, lower production, dominated by a diversity of shrubs and bluebunch wheatgrass/
R010XC055OR SR Mountain Shallow South 16-20 PZ
SR Shrubby Mountain Shallow South 16-20 PZ - Steeper south aspects, lower production, dominated by a diversity of shrubs and bluebunch wheatgrass.
R010XC069OR SR Mountain North 16-20 PZ
SR Mountain North 16-20 PZ - Steeper north aspects, greater production
Similar sites
R010XC069OR SR Mountain North 16-20 PZ
SR Mountain North 16-20 PZ - Steeper north aspects, greater production
R010XC032OR SR Mountain 12-16 PZ
SR Mountain 12-16 PZ - Lower elevation, different composition - more shrubs, less Idaho fescue
R010XC037OR SR Mountain Shallow 12-16 PZ
SR Mountain Shallow 12-16 PZ - Stony Loam surface texture, shallow to bedrock, lower production
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. vaseyana
Herbaceous (1) Festuca idahoensis
(2) EriogonumPhysiographic features
This site occurs on mountain ridges and plateaus adjacent to forestland. Slopes typically range from 2 to 12%. Elevations typically range from 6,000 to 7,500 feet.
Table 2. Representative physiographic features
Landforms (1) Ridge
(2) Plateau
Elevation 6000 – 7500 ft Slope 2 – 12 % Aspect Aspect is not a significant factor Climatic features
The annual precipitation ranges from 16 to 20 inches plus, most of which occurs in the form of snow during the months of December through March. Localized convection storms occasionally occur during the summer. The soil temperature regime is frigid with a mean air temperature of 42 degrees F. Temperature extremes range from 80 to -30 degrees F. The frost free period is less than 30 days. The optimum growth period for plant growth is late May through July.
Table 3 Representative climatic features
Frost-free period (average) 30 days Freeze-free period (average) Precipitation total (average) 20 in ">Influencing water features
Soil features
The soils of this site are typically moderately deep and well drained. Typically, the surface layer is a silt loam about 8 inches thick. The subsoil is a silt loam to stony clay loam about 20 inches thick. Depth to bedrock or an indurated pan ranges from 20 to 40 inches. Permeability is moderate. The available water holding capacity (AWC) is about 6 to 10 inches for the profile. The erosion potential is moderate to severe.
Table 4. Representative soil features
Surface texture (1) Silt loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate to moderately slow Soil depth 20 – 40 in Surface fragment cover <=3" 0 – 10 % Surface fragment cover >3" 0 – 10 % Available water capacity
(0-40in)6 – 10 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Ecological dynamics
The potential native plant community is strongly dominated by Idaho fescue. Mountain big sagebrush and shrubby buckwheat (parsnip flower buckwheat)are scattered. A variety of other forbs and grass/grass-like plants, prairie unegrass, sedges and Sandberg bluegrass are present. Vegetative composition of the community is approximately 85 percent grasses, 10 percent forbs and 5 percent shrubs. Approximate ground cover is 80 to 90 percent (basal and crown).
Range in Characteristics:
Idaho fescue is strongly dominant. Bluebunch wheatgrass increases on slight south and west exposures. Sedges increase in moist areas. Shrubs increase in shallower areas and over fractured substratums. Production increases on deeper soils and at the upper end of the precipitation zone.
Response to Disturbance - States:
If the condition of the site deteriorates as a result of overgrazing, Idaho fescue decreases. Mountain big sagebrush increases. Mountain brome, Sandberg bluegrass and forbs increase. Juniper slowly invades from rocky areas. With continued overgrazing, mountain big sagebrush dominates the overstory. Mountain brome, Sandberg bluegrass and forbs dominate the understory. Annual invasion is limited unless ground disturbance occurs. With fire and heavy use or ground disturbance, unpalatable forbs, annuals and Sandberg-bulbous bluegrass continue increase. In moist areas Kentucky and Canada bluegrass invades. Bare ground rapidly increases and excessive erosion contributes to downstream sedimentation.
States: ARTRV/FORBS/BRMA4-POSE-Bare Ground; JUOC/ARTRV/FORBS/BRMA4-POSE-Bare Ground; FORBS/POA complex -Annuals-Bare Ground
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
ReferenceCommunity 1.1
Reference Plant CommunityThe potential native plant community is strongly dominated by Idaho fescue. Mountain big sagebrush and shrubby buckwheat (parsnip flower buckwheat)are scattered. A variety of other forbs and grass/grass-like plants, prairie unegrass, sedges and Sandberg bluegrass are present. Vegetative composition of the community is approximately 85 percent grasses, 10 percent forbs and 5 percent shrubs. Approximate ground cover is 80 to 90 percent (basal and crown).
Figure 1. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Grass/Grasslike 1020 1360 1700 Forb 120 160 200 Shrub/Vine 60 80 100 Total 1200 1600 2000 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant, deep rooted perennial bunchgrass 1120–1280 Idaho fescue FEID Festuca idahoensis 1120–1280 – 4 Other perennial grasses 35–160 sedge CAREX Carex 10–32 – prairie Junegrass KOMA Koeleria macrantha 10–32 – basin wildrye LECI4 Leymus cinereus 0–32 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 5–32 – Sandberg bluegrass POSE Poa secunda 5–16 – mountain brome BRMA4 Bromus marginatus 5–16 – Forb7 Dominant perennial forbs 32–48 parsnipflower buckwheat ERHE2 Eriogonum heracleoides 32–48 – 8 Sub-dominant perennial forbs 64–128 tapertip hawksbeard CRAC2 Crepis acuminata 16–32 – desertparsley LOMAT Lomatium 16–32 – lupine LUPIN Lupinus 16–32 – ragwort SENEC Senecio 16–32 – 9 Other perennial forbs 29–128 milkvetch ASTRA Astragalus 5–16 – arrowleaf balsamroot BASA3 Balsamorhiza sagittata 5–16 – Scouler's woollyweed HISC2 Hieracium scouleri 5–16 – waterleaf HYDRO4 Hydrophyllum 0–16 – woodland-star LITHO2 Lithophragma 2–10 – stoneseed LITHO3 Lithospermum 0–10 – sagebrush buttercup RAGL Ranunculus glaberrimus 2–10 – mariposa lily CALOC Calochortus 2–10 – Indian paintbrush CASTI2 Castilleja 2–10 – fleabane ERIGE2 Erigeron 2–10 – buckwheat ERIOG Eriogonum 2–10 – common yarrow ACMI2 Achillea millefolium 2–10 – Shrub/Vine11 Dominant evergreen shrub 48–128 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 48–128 – 15 Other shrubs 5–74 Saskatoon serviceberry AMAL2 Amelanchier alnifolia 0–16 – wax currant RICE Ribes cereum 0–16 – Woods' rose ROWO Rosa woodsii 0–16 – common snowberry SYAL Symphoricarpos albus 5–16 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 0–10 – Tree16 Evergreen sub-dominant trees 0–32 western juniper JUOC Juniperus occidentalis 15–30 – ponderosa pine PIPO Pinus ponderosa 15–30 – ponderosa pine PIPO Pinus ponderosa 0–16 – Douglas-fir PSME Pseudotsuga menziesii 0–16 – Interpretations
Animal community
Livestock grazing:
This site is suitable for livestock grazing use in the summer, and early fall under a planned grazing system. Use should be postponed until the soils are firm enough to prevent trampling damage and soil compaction. Grazing management should be keyed to Idaho fescue. Deferred grazing or rest is recommended at least once every three years.
Native Wildlife Associated with the Potential Climax Community:
This site is commonly used by mule deer, elk, rabbits, rodents, upland birds and various predators. It is a preferred site for upland bird nesting and rearing areas. Mule deer and elk make excellent use of the site for summer and fall forage. Nearby forested areas provide escape, hiding, and thermal cover.
Hydrological functions
The soils of this site are typically in an upland topographic position. They have moderate high runoff potential and medium infiltration rates when the hydrologic cover is high. Under frozen ground conditions runoff potential is significantly increased. This occurs for extended periods when deep rooted perennial bunchgrass cover is negligible. Hydrologic cover is good when the Idaho fescue deep rooted bunchgrass component is >70 percent of potential.
Other information
Juniper invasion from rock outcrops is a moderate risk on this site. Increases in western juniper and the subsequent competition for moisture will lead to a reduction of available forage. Overgrazing can easily reduce ground cover and accelerate soil loss. Juniper control measures include prescribed burning and/or cutting followed by rest to improve vigor, density and seed production of existing deep rooted perennial bunchgrasses. Consider seeding following control measures if an inadequate stand of bunchgrass is present.
When incised channels are present, rehabilitation will markedly improve production, reduce downstream sedimentation, and restore good hydrologic characteristics. On altered sites, the reintroduction of Idaho fescue and basin wildrye may be needed to fully restore the site potential.
Supporting information
Contributors
T.Bloomer, E.Petersen, A.Bahn
Approval
Kirt Walstad, 4/10/2025
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) Jeff Repp, Bruce Frannsen Contact for lead author NRCS Oregon State Rangeland Management Specialist Date 07/11/2007 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
None, Moderate to severe sheet & rill erosion hazard -
Presence of water flow patterns:
None -
Number and height of erosional pedestals or terracettes:
None to very few (some frost heaving) -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-15% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None, Moderate wind erosion hazard -
Amount of litter movement (describe size and distance expected to travel):
Fine - limited movement -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Significantly resistant to erosion: aggregate stability = 4-6 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Granular to platy to sub-angular blocky structure; Dry color value 4-5; 3-9" thickness; Low to moderate OM (1-4%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Moderate to significant ground cover (60-70%) and gentle slopes (2-12%) effectively limit rainfall impact and overland flow -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None -
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:
Deep rooted, perennial, cool-season bunchgrassesSub-dominant:
shrubsOther:
other grasses > forbsAdditional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Normal decadence and mortality expected -
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):
Favorable: 2000, Normal: 1500, Unfavorable: 1000 lbs/acre/year at high RSI (HCPC) -
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:
Perennial brush species will increase with deterioration of plant community. Western Juniper readily invades the site. Cheatgrass and Medusahead invade sites that have lost deep rooted perennial grass functional groups -
Perennial plant reproductive capability:
All species should be capable of reproducing annually
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