Natural Resources
Conservation Service
Ecological site R010XA027OR
Juniper Pumice Flat 8-10 PZ
Accessed: 12/22/2024
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
| R010XA022OR |
Juniper Lava Blisters 8-10 PZ Lava Blisters 8-10 pz |
|---|
Similar sites
| R010XA009OR |
Juniper Shrubby Pumice Flat 10-12 PZ Pumice Flat 10-12 pz, higher precipitation and production. |
|---|---|
| R010XA021OR |
Juniper Shallow Pumice Hills 10-12 PZ Shallow Pumice Hills 10-12 pz. Dominated by Idaho fescue. Frigid temperature regime. |
Table 1. Dominant plant species
| Tree |
(1) Juniperus occidentalis |
|---|---|
| Shrub |
(1) Artemisia tridentata ssp. tridentata |
| Herbaceous |
(1) Hesperostipa comata |
Physiographic features
This site occurs on nearly level plains and gentle slopes of low hills.
Table 2. Representative physiographic features
| Landforms |
(1)
Plain
(2) Hill |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,800 – 4,000 ft |
| Slope | 10% |
| Aspect | Aspect is not a significant factor |
Climatic features
The annual precipitation ranges from 8 to 10 inches which occurs mainly between the months of November 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 -10 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) | 10 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 moderately deep or deep, well drained and sandy loam (medium) textured. They are generally formed in pumice ash over basalt bedrock. Permeability is moderately rapid and the available water holding capacity is 1 to 7 inches for the profile. The potential for wind erosion is high.
Table 4. Representative soil features
| Surface texture |
(1) Sandy loam (2) Ashy sandy loam (3) Loamy sand |
|---|---|
| Family particle size |
(1) Sandy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderately rapid |
| Soil depth | 20 – 60 in |
| Surface fragment cover <=3" | 25% |
| Surface fragment cover >3" | 20% |
| Available water capacity (0-40in) |
1.1 – 7.3 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) |
33% |
| Subsurface fragment volume >3" (Depth not specified) |
25% |
Ecological dynamics
Burning reduces sagebrush and juniper, while increasing the cover of rabbitbrush. Overgrazing damages Idaho fescue, needle and thread, Indian ricegrass, and Ross sedge, but encourages rabbitbrush, granite prickly phlox, cheatgrass, squirreltail, and weeds. Juniper clearing will be detrimental to Idaho fescue which is dependent on the overstory effects for its occurrence.
Increasers and invaders include rubber rabbitbrush, cheatgrass, mustard, collinsia, and gray parsely.
Local areas with pockets of deeper sand or pumice may have greater amounts of bitterbrush.
Disturbance Response:
Three primary disturbances were identified for this site: grazing, tree cutting, and the infrequent small area fire.
Inappropriate grazing causes a reduction in needle and thread (HECOC8), Indian ricegrass (ACHY), and other understory grass species. Idaho fescue (FEID) remains 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 (LIPU11) increases and grasses decline. Squirreltail (ELEL5) may increase initially as needle and thread declines, however with continued overgrazing this species will also decline. Eventually deep rooted perennial bunchgrasses (DRPBG) are eliminated. Cheatgrass becomes dominate along with rubber rabbitbrush (ERNA10). Ground fire potential increases with increasing cheatgrass, however fires would be infrequent and small in area.
Cutting of juniper (JUOC) leads to an increase in rubber rabbitbrush and an increase in cheatgrass with or without grazing. Idaho fescue is eliminated from areas where trees are removed due to harsh microclimate and cheatgrass replaces it. 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 extremely infrequent in the historical community and limited to single tree or small area events (Miller, R. pers. comm. 2006). 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. Fire would reduce the amount of sagebrush while increasing cheatgrass and other annuals.
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 an open stand of juniper. The understory is composed of two distinct communities in complex with each other. Under the trees and within influence of the crown is an Idaho fescue dominated ground layer. The interspaces between the trees (openings) are dominated by mountain and basin big sagebrush, needle and thread, and several other minor species such as Indian ricegrass, western needlegrass, and Thurber's needlegrass. Vegetative composition is approximately 75% grasses, 5% forbs, and 20% 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 | 450 | 600 | 750 |
| Shrub/Vine | 90 | 120 | 150 |
| Tree | 30 | 40 | 50 |
| Forb | 30 | 40 | 50 |
| Total | 600 | 800 | 1000 |
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 | 240–400 | ||||
| needle and thread | HECO26 | Hesperostipa comata | 240–400 | – | ||
| 2 | Perennial, bunch-grass, deep-rooted | 60–100 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 60–100 | – | ||
| 3 | Perennial, bunch-grass, deep-rooted | 90–150 | ||||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 30–50 | – | ||
| western needlegrass | ACOCO | Achnatherum occidentale ssp. occidentale | 30–50 | – | ||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 30–50 | – | ||
| 4 | Perennial, bunch-grass, deep-rooted | 54–90 | ||||
| thickspike wheatgrass | ELLA3 | Elymus lanceolatus | 18–30 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 12–20 | – | ||
| Ross' sedge | CARO5 | Carex rossii | 12–20 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 6–10 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 6–10 | – | ||
|
Forb
|
||||||
| 9 | Other perennial forbs | 30–50 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–5 | – | ||
| pussytoes | ANTEN | Antennaria | 0–5 | – | ||
| larkspur | DELPH | Delphinium | 0–5 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–5 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–5 | – | ||
| starlily | LEUCO | Leucocrinum | 0–5 | – | ||
| lupine | LUPIN | Lupinus | 0–5 | – | ||
| phacelia | PHACE | Phacelia | 0–5 | – | ||
| spreading phlox | PHDI3 | Phlox diffusa | 0–5 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Dominant evergreen shrubs | 42–70 | ||||
| basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 21–70 | – | ||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 21–70 | – | ||
| 12 | Sub-dominant evergreen shrubs | 30–50 | ||||
| spiny hopsage | GRSP | Grayia spinosa | 30–50 | – | ||
| 15 | Other shrubs | 18–30 | ||||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–10 | – | ||
| granite prickly phlox | LIPU11 | Linanthus pungens | 0–10 | – | ||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 0–10 | – | ||
| desert gooseberry | RIVE | Ribes velutinum | 0–10 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 0–10 | – | ||
|
Tree
|
||||||
| 16 | Dominant evergreen trees | 30–50 | ||||
| western juniper | JUOC | Juniperus occidentalis | 30–50 | – | ||
Interpretations
Animal community
This site is suitable to grazing by livestock.
Wildlife associated with this site include Mule deer, coyote, and passerine birds.
Hydrological functions
The soils of this site have high infiltation rates and low runoff potential.
Wood products
Firewood and fence posts.
Other products
This site is usually without natural sources of livestock water.
Other information
For range seedings, recommended species are crested wheatgrass, Siberian wheatgrass, thickspike wheatgrass, tall wheatgrass, and Indian ricegrass.
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 - 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):
20-30% -
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):
Slightly to moderately resistant to erosion: aggregate stability = 2-5 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
single grain to moderate very fine granular structure, dry color value 4-5, 7-12 inches thick; low organic matter content (1-2%). -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (60-70%) and moderate slopes (0-10%) 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:
Perennial, deep-rooted bunch-grassesSub-dominant:
Evergreen shrubsOther:
Evergreen trees = perennial forbs > other shrubsAdditional:
-
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: 1000, Normal: 800, Unfavorable: 600 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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