Natural Resources
Conservation Service
Ecological site R010XA002OR
Juniper Shrubby Pumice Hills
8-10 PZ
Last updated: 4/10/2025
Accessed: 04/17/2026
-
Search
Major Land Resource Area or ecological site by name and/or ID.
PreviousSectionsNextGeneral 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.
Click to explore map
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
R010XA007OR Juniper Pumice South 9-12 PZ
SOUTH 10-12 PZ
R010XA083OR Juniper Shrubby North 9-12 PZ
SANDY NORTH 10-12 PZ
R010XA001OR Loamy 8-10 PZ
DROUGHTY LOAM 8-10 PZ
R010XA018OR Juniper Shrubby Loam 10-12 PZ
LOAMY 10-12 PZ
Similar sites
R010XA027OR Juniper Pumice Flat 8-10 PZ
PUMICE FLAT 8-10 PZ
Table 1. Dominant plant species
Tree (1) Juniperus occidentalis
Shrub (1) Artemisia tridentata ssp. tridentata
(2) Purshia tridentataHerbaceous (1) Hesperostipa comata
(2) Oryzopsis hymenoidesPhysiographic features
This site occurs on flat to gentle slopes and swales in uplands; also on dry basins, drainage terraces, fans, or slopes adjacent to bottomlands.
Table 2. Representative physiographic features
Landforms (1) Swale
(2) Terrace
(3) Fan
Flooding frequency None Ponding frequency None Elevation 610 – 1067 m Slope 0 – 30 % Aspect Aspect is not a significant factor Climatic features
The annual precipitation typically ranges from 8 to 10 inches, but occasionally up to 12 inches. Most precipitation occurs between November and early 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 freeze free period is 90 to 120 days. The optimum period for plant growth is from early March through June.
Table 3 Representative climatic features
Frost-free period (average) 120 days Freeze-free period (average) 120 days Precipitation total (average) 250 mm BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
The soils of this site are moderately deep to deep, well or excessively drained, and have sandy textured surfaces. Subsoils are sandy and sometimes gravelly. They are generally formed in isolated deposits of volcanic ash. Permeability is moderately rapid and the available water holding capacity is 4 to 6.7 inches for the profile. The potential for wind erosion is high.
Table 4. Representative soil features
Surface texture (1) Very gravelly sandy loam
(2) Ashy sandy loam
(3) Loam
Family particle size (1) Sandy
Drainage class Well drained to somewhat excessively drained Permeability class Moderately rapid to moderately slow Soil depth 51 – 152 cm Surface fragment cover <=3" 0 – 37 % Surface fragment cover >3" Not specified Available water capacity
(0-101.6cm)10.16 – 17.02 cm Calcium carbonate equivalent
(0-101.6cm)Not specified Electrical conductivity
(0-101.6cm)0 – 2 mmhos/cm Sodium adsorption ratio
(0-101.6cm)Not specified Soil reaction (1:1 water)
(0-101.6cm)6.1 – 7.8 Subsurface fragment volume <=3"
(Depth not specified)0 – 18 % Subsurface fragment volume >3"
(Depth not specified)0 – 9 % Ecological dynamics
The existence of the reference state today is rare or not at all, therefore it is presented in this model as a reminder of what once was. Community changes were likely rare, spatially dispersed, and precipitated by small or single tree fires.
The ecological function of State 2 has not changed from that of the reference state, however the resiliency of the state has been reduced by the presence of cheatgrass.
Burning reduces the cover of sagebrush, bitterbrush, and juniper.
Increasers and invaders include cheatgrass, annual fescue, collinsia, fiddleneck, cryptantha, hemizonia, mustard, pepperweed, snakeweed, and rubber rabbitbrush.
The percent composition for several species, i.e., Idaho fescue, bluebunch wheatgrass, bitterbrush, and juniper may vary considerably depending on the locality, precipitation, and variations in soil characteristics.
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 (HECO26), indian ricegrass (ACHY), bluebunch wheatgrass (PSSP6), 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 and bluebunch wheatgrass decline, however with continued overgrazing this species will also decline. Eventually deep rooted perennial bunchgrasses (DRPBG) are eliminated. Cheatgrass becomes dominate along with rubber rabbitbrush (ERNAN5).
Cutting of juniper (JUOC) leads to an increase in grey rabbitbrush and 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 and bitterbrush while increasing cheatgrass and other annuals.
Ground fire potential increases with increasing cheatgrass, however fires would be infrequent and small in area.State and transition model
Custom diagramStandard diagram
More interactive model formats are also available. View Interactive Models
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 dominated by an open stand of juniper and needle and thread. Other prominent grasses include indian ricegrass, Thurber's needlegrass, Sandberg bluegrass, and bluebunch wheatgrass. Idaho fescue is usually poresent in high precipitation zones, but restricted to areas beneath the tree canopy if present in low precipoitation areas. Bitterbrush and big sagebrush are also present.
The vegetative composition of the community is approximately 75% grass, 10% forbs, and 15% 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
(kg/hectare)Representative value
(kg/hectare)High
(kg/hectare)Grass/Grasslike 504 673 841 Shrub/Vine 67 90 112 Forb 67 90 112 Tree 34 45 56 Total 672 898 1121 Figure 5. 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 () Foliar cover (%) Grass/Grasslike1 Perennial, bunch-grass, deep-rooted 336–560 needle and thread HECO26 Hesperostipa comata 336–560 – 2 Perennial, bunch-grass, deep-rooted 47–78 Indian ricegrass ACHY Achnatherum hymenoides 47–78 – 3 Perennial, bunch-grass, deep-rooted 34–56 Thurber's needlegrass ACTH7 Achnatherum thurberianum 34–56 – 4 Perennial, bunch-grass, deep-rooted 34–56 Idaho fescue FEID Festuca idahoensis 20–34 – bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 13–22 – 5 Perennial, bunch-grass, shallow-rooted 34–56 Sandberg bluegrass POSE Poa secunda 34–56 – 6 Other perennial grasses 7–34 Ross' sedge CARO5 Carex rossii 0–11 – squirreltail ELEL5 Elymus elymoides 0–11 – prairie Junegrass KOMA Koeleria macrantha 0–11 – basin wildrye LECI4 Leymus cinereus 0–11 – Forb7 Perennial 54–90 common yarrow ACMI2 Achillea millefolium 7–11 – pussytoes ANTEN Antennaria 7–11 – milkvetch ASTRA Astragalus 7–11 – hawksbeard CREPI Crepis 7–11 – fleabane ERIGE2 Erigeron 7–11 – desertparsley LOMAT Lomatium 7–11 – lupine LUPIN Lupinus 7–11 – spreading phlox PHDI3 Phlox diffusa 7–11 – 9 Other perennial forbs 13–22 agoseris AGOSE Agoseris 0–11 – woollypod milkvetch ASPU9 Astragalus purshii 0–11 – Douglas' dustymaiden CHDO Chaenactis douglasii 0–11 – phacelia PHACE Phacelia 0–11 – deathcamas ZIGAD Zigadenus 0–11 – Shrub/Vine11 Evergreen, dominant 20–34 basin big sagebrush ARTRT Artemisia tridentata ssp. tridentata 20–34 – 12 Evergreen, subdominant 13–22 slender buckwheat ERMI4 Eriogonum microthecum 13–22 – 13 Deciduous, dominant 20–34 antelope bitterbrush PUTR2 Purshia tridentata 20–34 – 15 Other shrubs 13–22 rubber rabbitbrush ERNA10 Ericameria nauseosa 0–11 – granite prickly phlox LIPU11 Linanthus pungens 0–11 – spineless horsebrush TECA2 Tetradymia canescens 0–11 – Tree16 Evergreen trees 34–56 western juniper JUOC Juniperus occidentalis 34–56 – Interpretations
Animal community
This site is suitable to grazing by livestock.
Mule deer, coyotes, and passerine birds may be found on this site.Hydrological functions
The soils of this site have high infiltration rates and low runoff potential.
Wood products
Firewood and posts.
Other information
Key species for cattle are needle and thread, indian ricegrass, Thurber needlegrass, Idaho fescue, and bluebunch wheatgrass. Species adapted to use in range seeding include crested wheatgrass, siberian wheatgrass, indian ricegrass, tall wheatgrass, secar bluebunch wheatgrass, and sheep fescue (in higher precipitation areas).
Supporting information
Other references
Site also associated with B10B Sites
Droughty South 9-12 PZ #010XB042OR
Droughty North 9-12 PZ #010XB084ORContributors
Cici Brooks
Gene Hickman
K.KennedyApproval
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 and Bruce Franssen Contact for lead author State Rangeland Management Specialist for NRCS - Oregon Date 04/24/2003 Approved by 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 to some -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
10-15% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
Some to few -
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 resistant to erosion: aggregate stability = 3-4 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak very fine to fine granular structure, dry color value 5-6, 8 to 10 inches thick; low OM (1-2%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (55-65%) and level to moderately steep slopes 0-30%) moderately 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-grasses > perennial forbsSub-dominant:
Evergreen shrubs >= deciduous shrubsOther:
Evergreen treesAdditional:
-
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
Print Options
Sections
Font
AAAAOther
PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
Accessibility statement
