Natural Resources
Conservation Service
Ecological site R010XB030OR
JD Loamy 12-16 PZ
Accessed: 11/13/2024
General information
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
| R010XB027OR |
JD Clayey 12-16 PZ JD Clayey 12-16" PZ |
|---|---|
| R010XB031OR |
JD Shallow 12-16 PZ JD Shallow 12-16 PZ |
| R010XB032OR |
JD Very Shallow 12-16 PZ JD Very Shallow 12-16 PZ |
Similar sites
| R010XB027OR |
JD Clayey 12-16 PZ JD Clayey 12-16" PZ (clayey soil, composition difference, lower production) |
|---|---|
| R010XB031OR |
JD Shallow 12-16 PZ JD Shallow 12-16" PZ (shallower soil, lower production) |
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
Not specified |
Physiographic features
This site occurs on rolling uplands and plateaus. Slopes range from 0 to 20 percent. Elevation varies from 2100 to 4000 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Plateau
(2) Hill |
|---|---|
| Elevation | 2,100 – 4,000 ft |
| Slope | 20% |
| Water table depth | 60 in |
| Aspect | Aspect is not a significant factor |
Climatic features
The annual precipitation ranges from 12 to 16 inches. The precipitation occurs as rain and snow during the months of November through March. Localized, occasionally severe, convection storms occur during the summer. The mean annual air temperature is approximately 50 degrees F. Extreme temperatures range from 100 degrees F to -10 degrees F. Soil temperature regimes are mesic to near frigid. The frost-free period ranges from 90 to 150 days. The period of optimum plant growth is from April through mid-July.
Table 3. Representative climatic features
| Frost-free period (average) | 150 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 16 in |
Influencing water features
Soil features
The soils of this site are formed on colluvium and loess over basalt and tuff. They are moderately deep to deep. Typically the surface layer is a silt loam or loam over a loamy to clay loam subsoil. Depth to bedrock is 30 to 60 inches. Soil permeability is moderate. The available water holding capacity (AWC) is 5 to 8 inches. The erosion potential is moderate.
Table 4. Representative soil features
| Surface texture |
(1) Silt loam (2) Loam |
|---|---|
| Family particle size |
(1) Clayey |
| Drainage class | Well drained |
| Permeability class | Moderate |
| Soil depth | 30 – 60 in |
| Available water capacity (0-40in) |
5 – 8 in |
Ecological dynamics
Range in Characteristics:
Variability in plant composition and production is dependent on soil depth and texture. Bluebunch wheatgrass increases on fine textured surfaces. Thurber needlegrass and needle-and-thread increase on coarse textured surfaces. Production increases with soil depth.
Response to Disturbance:
If the condition of the site deteriorates as a result of overgrazing, bluebunch wheatgrass, Idaho fescue, and needlegrass decrease while basin big sagebrush and western juniper increase. Cheatgrass and other annuals invade. Both basin big sagebrush and western juniper strongly increase in the absence of fire. With continued deterioration, areas of bare soil increase, soil erosion accelerates, and potential site productivity decreases.
Juniper Response:
Fine fuel reduction from improper grazing and fire suppression has led to an increase in the historical fire return interval on many western rangelands. A reduction in fire frequency on these sites leads to an increase in juniper cover, a decrease in sagebrush cover followed by a decrease in herbaceous cover and understory diversity. As juniper encroaches on north facing aspects sagebrush declines with a subsequent decrease in forbs, bluebunch wheatgrass and needlegrass. Idaho fescue becomes the primary herbaceous species occurring under the canopy of the juniper trees. Sandberg’s bluegrass increases in the plant community on lower elevation north slopes and warmer non-aspect sites while bare ground increases in the interspaces between trees. Bitterbrush is more resistant to juniper encroachment than sagebrush and maintains its presence in the community, however vigor and fitness (seed production) may be thwarted. The potential for soil erosion increases as the juniper woodland matures and the understory plant community cover declines. The combined effect of overgrazing and juniper invasion increases the rate of decline in ecological function and the probability of crossing a threshold is high.
Treatment Response:
This site responds positively to juniper removal if soil erosion is not significant. Seeding may be necessary if there are less than 1-2 bunchgrass plants per meter square in the understory. Forbs may also need to be seeded if adult plants are no longer present in the understory.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant Community
Community 1.1
Historic Climax Plant Community
The potential native plant community is dominated by bluebunch wheatgrass. Idaho fescue, Thurber needlegrass, and needle-and-thread are common. Basin big sagebrush and minor amounts of other shrubs are present. Juniper is sporadic. The potential vegetative composition is approximately 90 percent grasses, 5 percent forbs, and 5 percent shrubs. Approximate ground cover is 60-70 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 | 1408 | 1704 | 2000 |
| Forb | 64 | 168 | 272 |
| Shrub/Vine | 32 | 88 | 144 |
| Tree | 16 | 24 | 32 |
| Total | 1520 | 1984 | 2448 |
Additional community tables
Table 6. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Perennial, deep-rooted, dominant | 1120–1280 | ||||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 1120–1280 | – | ||
| 2 | Perennial, deep-rooted, sub-dominant | 240–560 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 80–240 | – | ||
| needle and thread | HECO26 | Hesperostipa comata | 80–160 | – | ||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 80–160 | – | ||
| 5 | Other perennial grasses, all | 48–160 | ||||
| squirreltail | ELEL5 | Elymus elymoides | 0–40 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–40 | – | ||
| basin wildrye | LECI4 | Leymus cinereus | 0–40 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 0–40 | – | ||
|
Forb
|
||||||
| 7 | Perennial, all, dominant | 48–144 | ||||
| milkvetch | ASTRA | Astragalus | 16–48 | – | ||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 16–48 | – | ||
| lupine | LUPIN | Lupinus | 16–48 | – | ||
| 9 | Other perennial forbs, all | 16–128 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–18 | – | ||
| agoseris | AGOSE | Agoseris | 0–18 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–18 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–18 | – | ||
| desertparsley | LOMAT | Lomatium | 0–18 | – | ||
| grasswidow | OLSYN | Olsynium | 0–18 | – | ||
| phlox | PHLOX | Phlox | 0–18 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Perennial, evergreen, dominant | 16–48 | ||||
| basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 16–48 | – | ||
| 15 | Other perennial shrubs, all | 16–96 | ||||
| Saskatoon serviceberry | AMAL2 | Amelanchier alnifolia | 0–19 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–19 | – | ||
| green rabbitbrush | ERTE18 | Ericameria teretifolia | 0–19 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 0–19 | – | ||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 0–19 | – | ||
|
Tree
|
||||||
| 16 | Perennial, evergreen, dominant | 16–32 | ||||
| ponderosa pine | PIPO | Pinus ponderosa | 16–32 | – | ||
Interpretations
Animal community
Livestock Grazing:
This site is suited to spring, summer, and fall use by cattle, sheep, and horses under a planned grazing system. The key species is bluebunch wheatgrass. Bluebunch wheatgrass can be damaged if heavily grazed during periods of flowering and seed formation when root reserves and soil moisture is low. Use in the spring should be postponed until the soils are firm enough to prevent trampling damage and soil compaction.
Native Wildlife Associated with the Potential Climax Community:
Mule deer
elk
upland birds
When the ecological condition is high, this site provides food and cover for deer, elk, other mammals, and upland birds. It is an important wintering area for deer and elk.
Threatened and Endangered Animals:
Listed endangered species (1993), which may occur on this site include the peregrine falcon. Listed threatened species is the bald eagle.
Hydrological functions
The soils of this site have high water holding capacities providing late season water for plant growth. The hydrologic cover condition is good when the ecological condition is high.
Other information
When in poor condition this site has high potential for range seeding because it is moderately deep to deep, non-stony, not droughty, and occurs on gentle slopes.
Supporting information
Contributors
A V Bahn
M. Parks (OSU)
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 and Bruce Frannsen |
|---|---|
| Contact for lead author | State Rangeland Management Specialist for NRCS - Oregon |
| Date | 08/06/2012 |
| Approved by | Bob Gillaspy |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None, moderate sheet & rill erosion hazard -
Presence of water flow patterns:
None -
Number and height of erosional pedestals or terracettes:
None -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-10% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None, slight 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):
Moderately deep to deep, well drained silt loams and loams: moderate OM (2-4%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Moderate ground cover (60-70%) and gentle slopes (0-20%) 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:
Bluebunch wheatgrass > Idaho fescue > other grasses > shrubs > forbsSub-dominant:
Other:
Additional:
-
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):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 2000, Normal: 1600, Unfavorable: 1200 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:
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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