Natural Resources
Conservation Service
Ecological site R010XA009OR
Juniper Shrubby Pumice Flat 10-12 PZ
Accessed: 03/23/2025
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
| R010XA019OR |
Shrubby Loam 8-12 PZ Droughty 8-12 PZ, lower precipitation and production. Domnated by bluebunch wheatgrass. |
|---|---|
| R010XA023OR |
Juniper Lava Shrubby Blisters 10-12 PZ Lava Blisters 10-12 PZ, lower production due to shallower site. |
Similar sites
| R010XA027OR |
Juniper Pumice Flat 8-10 PZ Pumice Flat 8-10 PZ, lower precipitation. |
|---|
Table 1. Dominant plant species
| Tree |
(1) Juniperus occidentalis |
|---|---|
| Shrub |
(1) Purshia tridentata |
| Herbaceous |
(1) Festuca idahoensis |
Physiographic features
This site occurs on nearly level to gentle uplands.
Table 2. Representative physiographic features
| Landforms |
(1)
Lava plain
(2) Outwash plain (3) Stream terrace |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,500 – 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 48 degrees F. with extreme temperatures ranging from -27 to 105 degrees F. The frost free period is 40 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) | 130 days |
| Precipitation total (average) | 12 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils of this site are typically moderately deep to deep, somewhat excessively drained and coarse textured. They are generally formed in volcanic ash. Permeability is rapid and the available water holding capacity is 3 to 6 inches for the profile. The potential for water or wind erosion is slight to moderate, depending on slope.
Table 4. Representative soil features
| Surface texture |
(1) Ashy sandy loam (2) Loamy sand |
|---|---|
| Family particle size |
(1) Sandy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderately rapid to rapid |
| Soil depth | 20 – 60 in |
| Surface fragment cover <=3" | 10% |
| Surface fragment cover >3" | Not specified |
| Available water capacity (0-40in) |
2.5 – 6 in |
| Calcium carbonate equivalent (0-40in) |
Not specified |
| Electrical conductivity (0-40in) |
2 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
Not specified |
| Soil reaction (1:1 water) (0-40in) |
6.6 – 7.8 |
| Subsurface fragment volume <=3" (Depth not specified) |
35% |
| Subsurface fragment volume >3" (Depth not specified) |
5% |
Ecological dynamics
For most of this site, Idaho fescue (FEID) is concentrated beneath or near the canopy of juniper trees (JUOC) where it dominates the ground cover. Needle and thread (HECOC8) (plus most of the other grasses) are concentrated in the interspaces between trees where it dominates the ground cover. However, when this site is adjacent to the pine forest boundary, needle and thread disappears and Idaho fescue dominates the interspaces as well.
Disturbance Response
Three primary disturbances were identified for this group: grazing, tree cutting and the infrequent small area fire.
Inappropriate grazing causes a reduction in Idaho fescue, needle and thread, Indian ricegrass (ACHY), and Thurber needlegrass (ACTH7), which encourages rubber rabbitbrush ERNA10), granite prickly phlox (LIPU), squirreltail (ELEL5), and weeds. Idaho fescue may remain in the community under the north side canopy of juniper trees and cheatgrass (BRTE), if present, will increase on all other aspects under the canopy. Interspaces are normally sparse, however with overgrazing granite prickly phlox increases and grasses decline. Squirreltail may increase initially as needle and thread and Idaho fescue decline, however with continued overgrazing this species will also decline. Eventually deep rooted perennial bunchgrasses (DRPBG) are eliminated. Cheatgrass becomes dominant along with rubber rabbitbrush. Ground fire potential increases with increasing cheatgrass.
Juniper clearing is detrimental to Idaho fescue where fescue does not grow in the interspaces, since it is dependent on the overstory effects for its survival. Cutting of juniper (JUOC) leads to an increase in rubber rabbitbrush and an increase in cheatgrass with or without grazing. The addition of inappropriate grazing would lead to a decline in the other deep-rooted perennial bunchgrasses and an increase in annuals and granite prickly phlox.
Fire was infrequent in the historical community and limited to single tree or small area events (Miller, R. pers. comm. 2006). Fire was responsible for the maintenance of a grass or shrub steppe savanna. With the reduction in fire frequency trees invade rapidly reducing the understory shrub community. With juniper cutting and/or improper grazing cheatgrass will dominate the understory and the probability of ground fire increases, however without ladder fuels the fire would be small in extent. Burning reduces sagebrush (ARTRV), bitterbrush (PUTR2), and juniper while increasing cover of rabbitbrush. Fire may allow cheatgrass and other annuals to invade this site.
Inappropriate grazing, juniper thinning and fire can lead to an increase in cheatgrass particularly on the south side of the juniper canopies.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference Plant Community
Community 1.1
Reference Plant Community
The potential native plant community is dominated by western juniper, mountain big sagebrush, bitterbrush, Idaho fescue, needle and thread. Vegetative composition is approximately 70% grasses, 5% forbs, and 25% shrubs/trees.
Figure 4. 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 | 490 | 630 | 770 |
| Shrub/Vine | 140 | 180 | 220 |
| Tree | 35 | 45 | 55 |
| Forb | 35 | 45 | 55 |
| Total | 700 | 900 | 1100 |
Figure 5. Plant community growth curve (percent production by month). OR4011, B10A Mesic, Mid Elev., N/A, Good Condition. RPC Growth Curve (Pumice Flats).
| 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 | 2 | 10 | 58 | 28 | 2 | 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 | Perennial, bunch-grass, deep-rooted | 210–330 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 210–330 | – | ||
| 2 | Perennial, bunch-grass, deep-rooted | 140–220 | ||||
| needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 140–220 | – | ||
| 3 | Perennial, bunch-grass, deep-rooted | 119–187 | ||||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 35–55 | – | ||
| western needlegrass | ACOC3 | Achnatherum occidentale | 28–44 | – | ||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 21–33 | – | ||
| thickspike wheatgrass | ELLA3 | Elymus lanceolatus | 21–33 | – | ||
| Ross' sedge | CARO5 | Carex rossii | 14–22 | – | ||
| 5 | Other perennial grasses | 21–33 | ||||
| squirreltail | ELEL5 | Elymus elymoides | 0–11 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 0–11 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 0–11 | – | ||
|
Forb
|
||||||
| 9 | Other perennial forbs | 35–55 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–22 | – | ||
| pussytoes | ANTEN | Antennaria | 0–22 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–22 | – | ||
| starlily | LEUCO | Leucocrinum | 0–22 | – | ||
| desertparsley | LOMAT | Lomatium | 0–22 | – | ||
| lupine | LUPIN | Lupinus | 0–22 | – | ||
| phacelia | PHACE | Phacelia | 0–22 | – | ||
| phlox | PHLOX | Phlox | 0–22 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Deciduous, dominant | 70–110 | ||||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 70–110 | – | ||
| 12 | Evergreen, dominant | 35–55 | ||||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 35–55 | – | ||
| 15 | Other shrubs | 35–55 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–22 | – | ||
| slender buckwheat | ERMI4 | Eriogonum microthecum | 0–22 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–22 | – | ||
| granite prickly phlox | LIPU11 | Linanthus pungens | 0–22 | – | ||
| desert gooseberry | RIVE | Ribes velutinum | 0–22 | – | ||
|
Tree
|
||||||
| 16 | Evergreen trees | 35–55 | ||||
| western juniper | JUOC | Juniperus occidentalis | 35–55 | – | ||
Interpretations
Animal community
Mule deer use this site as winter range. This site is suited to use by livestock in all seasons under a planned grazing system.
Hydrological functions
The soils of this site have high infiltration rates and low runoff potential.
Wood products
Fence posts, firewood, and speciality products.
Other products
Natural stock watering sources are not normally available on this site.
Other information
For range seedings, recommended species are crested wheatgrass, Siberian wheatgrass, thickspike wheatgrass, Indian ricegrass, and sheep fescue.
Supporting information
Contributors
Bob Gillaspy
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 Franssen. |
|---|---|
| Contact for lead author | State Rangeland Management Specialist for NRCS in Oregon. |
| Date | 04/24/2003 |
| Approved by | Bob Gillaspy |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None -
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):
15-30% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None to some -
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):
Moderately resistant to erosion: aggregate stability = 4-5 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak to moderate very fine granular structure, dry color value 4-5, 7-20 inches thick; low SOM (1-2%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (65-80%) and level to gently rolling slopes (0-20%) significantly 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 bunch-grassesSub-dominant:
Deciduous shrubs > evergreen shrubsOther:
perennial forbsAdditional:
-
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 -
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:
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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