Natural Resources
Conservation Service
Ecological site R010XA018OR
Juniper Shrubby Loam 10-12 PZ
Accessed: 10/30/2024
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.
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.
Associated sites
| R010XA009OR |
Juniper Shrubby Pumice Flat 10-12 PZ |
|---|
Similar sites
| R010XA019OR |
Shrubby Loam 8-12 PZ |
|---|---|
| R010XA001OR |
Loamy 8-10 PZ |
Table 1. Dominant plant species
| Tree |
(1) Juniperus occidentalis |
|---|---|
| Shrub |
(1) Purshia tridentata |
| Herbaceous |
(1) Pseudoroegneria spicata ssp. spicata |
Physiographic features
This site occurs on plateaus, ridgetops, and gently sloping to undulating uplands.
Table 2. Representative physiographic features
| Landforms |
(1)
Plateau
(2) Ridge |
|---|---|
| Elevation | 2,000 – 4,000 ft |
| Slope | 20% |
| Aspect | Aspect is not a significant factor |
Climatic features
The annual precipitation ranges from 10 to 12 inches which occurs mainly between the months of October and June, mostly in the form of rain and snow. The soil temperature regime is mesic. The average annual air temperature is 44 degrees F. with extreme temperatures ranging from -20 to 105 degrees F. The frost free period is 50 to 90 days. The optimum period for plant growth is from late March through June.
Table 3. Representative climatic features
| Frost-free period (average) | 90 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 12 in |
Influencing water features
Soil features
The soils of this site are shallow to moderately deep, well drained and medium textured. They are generally formed from loess and the underlying bedrock. Permeability is moderately slow and the available water holding capacity is 3 to 6 inches for the profile. The potential for water or wind erosion is low.
Table 4. Representative soil features
| Drainage class | Well drained |
|---|---|
| Permeability class | Moderately slow |
| Soil depth | 20 – 40 in |
| Available water capacity (0-40in) |
3 – 6 in |
Ecological dynamics
Overgrazing causes declines in bluebunch wheatgrass and Idaho fescue while Sandberg bluegrass, big sagebrush, and Thurber needlegrass increase. Burning results in a decline of juniper, sagebrush, bitterbrush and sometimes fescue, followed by invasions of weeds and rabbitbrush.
Bluebunch wheatgrass decreases while Idaho fescue and Thurber needlegrass increases on more coarse textured soils or on northerly aspects.
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 an open stand of western juniper, bitterbrush, big sagebrush, bluebunch wheatgrass, Idaho fescue, and Sandberg bluegrass. Thurber needlegrass and Junegrass are normally present but minor in the stand. A wide variety of forbs such as milkvetch, lupine, fleabane, yarrow, lomatium and hawksbeard occur along with small amounts of buckwheat. The vegetative composition is approximately 80% grasses, 5% forbs, and 15% shrubs/trees.
Figure 2. 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 | 486 | 671 | 855 |
| Shrub/Vine | 99 | 171 | 243 |
| Tree | 45 | 68 | 90 |
| Forb | 9 | 23 | 36 |
| Total | 639 | 933 | 1224 |
Figure 3. Plant community growth curve (percent production by month). OR4001, B10A Mesic, Low Elev., N/A, Sandy, Good Condition. B10A Mesic, Low Elev., N/A, Sandy, Good Condition RPC Growth Curve.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 5 | 20 | 55 | 15 | 5 | 0 | 0 | 0 | 0 | 0 |
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 | Dominant, perennial, deep rooted grasses | 405–675 | ||||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 270–405 | – | ||
| Idaho fescue | FEID | Festuca idahoensis | 135–270 | – | ||
| 2 | Sub-dominant, perennial, deep rooted grasses | 27–63 | ||||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 18–45 | – | ||
| Ross' sedge | CARO5 | Carex rossii | 9–18 | – | ||
| 4 | Sub dominant, perennial, shallow rooted grasses | 45–90 | ||||
| Sandberg bluegrass | POSE | Poa secunda | 45–90 | – | ||
| 5 | All other perennial grasses | 9–27 | ||||
| tufted wheatgrass | ELMA7 | Elymus macrourus | 2–7 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 2–7 | – | ||
| basin wildrye | LECI4 | Leymus cinereus | 2–7 | – | ||
| Cusick's bluegrass | POCU3 | Poa cusickii | 2–7 | – | ||
|
Forb
|
||||||
| 9 | All other perennial forbs | 9–36 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 1–3 | – | ||
| agoseris | AGOSE | Agoseris | 1–3 | – | ||
| pussytoes | ANTEN | Antennaria | 1–3 | – | ||
| Palouse milkvetch | ASAR7 | Astragalus arrectus | 1–3 | – | ||
| Idaho milkvetch | ASCO11 | Astragalus conjunctus | 1–3 | – | ||
| woollypod milkvetch | ASPU9 | Astragalus purshii | 1–3 | – | ||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 1–3 | – | ||
| fleabane | ERIGE2 | Erigeron | 1–3 | – | ||
| desertparsley | LOMAT | Lomatium | 1–3 | – | ||
| phacelia | PHACE | Phacelia | 1–3 | – | ||
| spreading phlox | PHDI3 | Phlox diffusa | 1–3 | – | ||
| salsify | TRPO | Tragopogon porrifolius | 1–3 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Dominant, perennial evergreen shrubs | 90–225 | ||||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 45–135 | – | ||
| basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 45–90 | – | ||
| 15 | All other perennial shrubs | 9–18 | ||||
| slender buckwheat | ERMI4 | Eriogonum microthecum | 1–2 | – | ||
| snow buckwheat | ERNI2 | Eriogonum niveum | 1–2 | – | ||
| wax currant | RICE | Ribes cereum | 1–2 | – | ||
| desert gooseberry | RIVE | Ribes velutinum | 1–2 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 1–2 | – | ||
|
Tree
|
||||||
| 16 | Dominant, perennial evergreen trees | 45–90 | ||||
| western juniper | JUOC | Juniperus occidentalis | 45–90 | – | ||
Interpretations
Animal community
Mule deer, hawks, coyotes, rabbits, and rodents
Hydrological functions
The soils of this site have high infiltration rates and moderate runoff potential.
Wood products
Fence posts, firewood, and specialty products.
Other products
This site is suited to use by livestock in all seasons. The key forage species are bluebunch wheatgrass and Idaho fescue.
Other information
Species suitable for range seedings inclue crested wheatgrass, Siberian wheatgrass, secar bluebunch wheatgrass, sheep fescue, and pubescent wheatgrass.
Supporting information
Other references
B10B sites also associated with this site include:
Droughty North 9-12 PZ #010XB084OR
JD North 9-12 PX
Contributors
Cici Brooks
E Ersch
Gene Hickman
K.Kennedy
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 | 08/03/2012 |
| Approved by | Bob Gillaspy |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None, Slight 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):
Shallow to moderately deep, well drained loams and cobbly loams; moderate OM (1-3%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (75-85%) and level to gently rolling slopes (0-20%) 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 > Sandberg bluegrass = Basin big sagebrush > Antelope bitterbrush = Western Juniper > other dominant grasses > other forbs > other grasses > other shrubsSub-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: 1100, Normal: 900, Unfavorable: 700 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 increases on 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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