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Conservation Service
Ecological site R010XA673OR
Juniper Pumice Hills
8-11 PZ
Last updated: 4/02/2025
Accessed: 07/12/2026
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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.
MLRA notes
Major Land Resource Area (MLRA): 010X–Central Rocky and Blue Mountain Foothills
This MLRA is characterized by gently rolling to steep hills, plateaus, and low mountains at the foothills of the Blue Mountains in Oregon and the Central Rocky Mountains in Idaho. The geology of this area is highly varied and ranges from Holocene volcanics to Cretaceous sedimentary rocks. Mollisols are the dominant soil order and the soil climate is typified by mesic or frigid soil temperature regimes, and xeric or aridic soil moisture regimes. Elevation ranges from 1,300 to 6,600 feet (395 to 2,010 meters), increasing from west to east. The climate is characterized by dry summers and snow dominated winters with precipitation averaging 8 to 16 inches (205 to 405 millimeters) and increasing from west to east. These factors support plant communities with shrub-grass associations with considerable acreage of sagebrush grassland. Big sagebrush, bluebunch wheatgrass, and Idaho fescue are the dominant species. Stiff sagebrush, low sagebrush, and Sandberg bluegrass are often dominant on sites with shallow restrictive layers. Western juniper is one of the few common tree species and since European settlement has greatly expanded its extent in Oregon. Nearly half of the MLRA is federally owned and managed by the Bureau of Land Management. Most of the area is used for livestock grazing with areas accessible by irrigation often used for irrigated agriculture.
Ecological site concept
In reference condition, this site supports a plant community dominated by scattered old growth western juniper (Juniperus occidentalis) in the overstory, mountain big sagebrush (Artemisia tridentata ssp. vaseyana) in the shrub layer and Idaho fescue (Festuca idahoensis) in the herbaceous layer. Abiotically, this site is characterized by typically moderately deep, well drained soils with ashy fine loam surface textures. The high ash content of these soils increases available water content and effective precipitation thereby facilitating the presence of species such as Idaho fescue and mountain big sagebrush. Historically, plant community dynamics were driven by disturbances such as fire, drought and insect/disease. Presently, reference conditions are less common and current dynamics are influenced by the spread of invasive species, infill of western juniper, livestock grazing pressures and fire suppression.
Associated sites
R010XA659OR Juniper Pumice Plains 8-11 PZ
Occupying adjacent plains
Similar sites
R010XA027OR Juniper Pumice Flat 8-10 PZ
mesic rather than frigid soil temperature regime
R010XA009OR Juniper Shrubby Pumice Flat 10-12 PZ
mesic rather than frigid soil temperature regime, higher precipitation
Table 1. Dominant plant species
Tree (1) Juniperus occidentalis
Shrub (1) Artemisia tridentata ssp. tridentata
Herbaceous (1) Festuca idahoensis
Physiographic features
This site is located on summits and plateaus of volcanic tablelands. This site occurs on all aspects. No water table is present within the soil profile. and the site is not subject to ponding or flooding.
Table 2. Representative physiographic features
Landforms (1) Tableland > Plateau
(2) Hills > Plateau
Flooding frequency None Ponding frequency None Elevation 4600 – 4900 ft Slope 0 – 20 % Aspect W, NW, N, NE, E, SE, S, SW Climatic features
This site has an aridic soil moisture regime and a frigid soil temperature regime characterized by hot dry summers and cold wet winters. Mean annual precipitation ranges from 8 to 11 inches (200 - 275 mm) and falls primarily as rain and snow from November through April. The frost-free period ranges from 85 to 95 days. Localized convection storms occasionally occur during the summer. Climate graphs are based on the nearest available climate stations to modal site locations and are provided to indicate general climate patterns.
Table 3 Representative climatic features
Frost-free period (characteristic range) 90-100 days Freeze-free period (characteristic range) 130-140 days Precipitation total (characteristic range) 10-10 in Frost-free period (average) 90 days Freeze-free period (average) 130 days Precipitation total (average) 10 in Characteristic rangeActual rangeBarLineFigure 1. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 2. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 3. Monthly maximum temperature range
BarLineFigure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6 Annual average temperature pattern
Climate stations used
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(1) BROTHERS [USC00351067], Brothers, OR
">Influencing water features
This site is not influenced by or associated with water features.
Wetland description
N/A
Soil features
Soils on this site are moderately deep Durixerolls with surface textures of fine loams. These are well drained soils formed in volcanic ash over residuum and colluvium from volcanic rock.
Table 4. Representative soil features
Parent material (1) Loess
(2) Residuum – volcanic rock
(3) Volcanic ash – volcanic rock
Surface texture (1) Ashy loam
(2) Ashy very fine sandy loam
Family particle size (1) Fine-loamy
Drainage class Well drained Permeability class Moderately rapid Depth to restrictive layer 20 – 40 in Soil depth 20 – 40 in Surface fragment cover <=3" 0 – 45 % Surface fragment cover >3" 0 – 45 % Available water capacity
(0-40in)3.4 – 4.8 in Soil reaction (1:1 water)
(0-40in)7.4 – 7.8 Subsurface fragment volume <=3"
(4-40in)0 – 20 % Subsurface fragment volume >3"
(4-60in)5 – 25 % Ecological dynamics
In its reference phase, this site is dominated by scattered old growth western juniper (Juniperus occidentalis) in the overstory, mountain big sagebrush (Artemisia tridentata ssp. vaseyana) in the shrub layer and Idaho fescue (Festuca idahoensis) in the herbaceous layer.
Disturbance and ecological dynamics:
While historical disturbances were most likely driven by climate, current disturbances include continued infill of western juniper, invasion of exotic annual grasses, and livestock grazing pressures. This site is considered a persistent juniper woodland, where at least some old growth juniper would be present even in the absence of altered disturbance regimes that have led to the encroachment of juniper throughout much of the Great Basin. Still, in its present state, this site is likely to have a much higher proportion of juniper than historically due to infill into these woodlands because of wildfire suppression, historic livestock grazing, and climate change (Bunting 1994). Persistent juniper woodlands often occur on sites with low productivity, coarse soils or protected rock outcrops and as such experience low fuel loading and discontinuous fuels. These conditions lead to very long fire return intervals that may range into the 100s of years (Miller 2019). Grazing disturbance may increase the plant community composition of Thurber's needlegrass (Achnatherum thurberianum) and squirreltail (Elymus elymoides) at the expense of Idaho fescue. This site may also be susceptible to invasion by exotic annual grasses. The invasion of sagebrush communities by cheatgrass (Bromus tectorum) has been linked to disturbances (fire, abusive grazing) that have resulted in fluctuations in resources (Chambers et al. 2007).
The state and transition model below represents a partial understanding of ecological dynamics on this site as they relate to grazing pressure. Future field work will further refine and expand this model to include other disturbance dynamics such as invasion by annual grasses and encroachment of juniper.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
T1A - Prolonged inappropriate grazing management R2A - Extended rest from grazing T2A - Continued prolonged inappropriate grazing management State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Historic ReferenceThis is the Historical Reference State, with the absence of an altered disturbance regime.
Dominant plant species
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western juniper (Juniperus occidentalis), tree
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basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
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bluebunch wheatgrass (Pseudoroegneria spicata ssp. spicata), grass
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Thurber's needlegrass (Achnatherum thurberianum), grass
Community 1.1
Reference Plant CommunityDominant plant species
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western juniper (Juniperus occidentalis), tree
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basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
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Idaho fescue (Festuca idahoensis), grass
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bluebunch wheatgrass (Pseudoroegneria spicata ssp. spicata), grass
Figure 7. 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 275 410 550 Shrub/Vine 50 75 100 Forb 40 65 85 Tree 35 50 65 Total 400 600 800 State 2
AlteredIn this state perennial grass composition has been significantly altered.
Dominant plant species
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western juniper (Juniperus occidentalis), tree
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basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
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Thurber's needlegrass (Achnatherum thurberianum), grass
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Idaho fescue (Festuca idahoensis), grass
Community 2.1
Altered Plant CommunityDominant plant species
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western juniper (Juniperus occidentalis), tree
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basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
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Thurber's needlegrass (Achnatherum thurberianum), grass
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Idaho fescue (Festuca idahoensis), grass
State 3
DisturbedIn this state, the community has lost a significant number of perennial grass species from the community, disturbance/early seral adapted species dominate.
Dominant plant species
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western juniper (Juniperus occidentalis), tree
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basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
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squirreltail (Elymus elymoides), grass
Community 3.1
Disturbed Plant CommunityDominant plant species
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western juniper (Juniperus occidentalis), tree
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basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
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squirreltail (Elymus elymoides), grass
Transition T1A
State 1 to 2Prolonged inappropriate grazing management leading to a change in perennial grass composition, marked by decreases in sensitive species such as Idaho fescue and bluebunch wheatgrass, and an increase in disturbance adapted species such as bottlebrush squirreltail and Thurber's needlegrass.
Restoration pathway R2A
State 2 to 1Extended rest from grazing allowing sensitive native grasses to increase in cover.
Context dependence.Excessive grazing leading to a loss of species diversity or reproductive output or altering abiotic conditions by significantly compacting or eroding soil, for example, will not recover by rest alone and will require additional inputs.
Transition T2A
State 2 to 3Continued prolonged inappropriate grazing management leading to a change in perennial grass composition and the loss of several species including Idaho fescue, bluebunch wheatgrass, and Thurber's needlegrass.
Constraints to recovery.Site has crossed an abiotic threshold that may only be rehabilitated by intensive restoration measures if at all.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Perennial Grasses 270–420 Idaho fescue FEID Festuca idahoensis 180–240 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 60–120 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 30–60 – 2 Other Perennial Grasses 12–30 squirreltail ELEL5 Elymus elymoides 0–12 – Forb4 Forbs 30–60 granite prickly phlox LIPU11 Linanthus pungens 6–12 – pussytoes ANTEN Antennaria 6–12 – erigenia ERIGE Erigenia 6–12 – phlox PHLOX Phlox 6–12 – buckwheat ERIOG Eriogonum 6–12 – 5 Other Forbs 6–18 lupine LUPIN Lupinus 0–6 – phacelia PHACE Phacelia 0–6 – common starlily LEMO4 Leucocrinum montanum 0–6 – common yarrow ACMI2 Achillea millefolium 0–6 – larkspur DELPH Delphinium 0–6 – Shrub/Vine7 Shrubs 30–60 basin big sagebrush ARTRT Artemisia tridentata ssp. tridentata 30–60 – 8 Other Shrubs 12–30 slender buckwheat ERMI4 Eriogonum microthecum 0–12 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–12 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 0–12 – Tree6 Trees 30–60 western juniper JUOC Juniperus occidentalis 30–60 – Table 7. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
GRAZING:
This site is suited to use under a planned grazing system by cattle. Care should be taken to avoid use until soils are sufficiently dry and stable as to reduce the impacts of trampling and root reserves have been established.
WILDLIFE:
This site is seasonally utilized by native ungulates (mule deer, elk, and antelope). Other animals that use this site are quail, coyotes, bobcats, and rabbits.
This site provides nesting and feeding cover to a variety of wildlife species. Use should be managed in such a manner as to maintain or improve conditions for wildlife populations.Wood products
This site has potential for fence posts or firewood.
Supporting information
Type locality
Location 1: Lake County, OR Township/Range/Section T24S R21E S30 General legal description Chicago valley quad in northern Lake County, T24S., R21E. NW NE Sec. 30. References
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1980. Fire Effects Information System. http://www.fs.fed.us/database/feis/.
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. 2021 (Date accessed). USDA PLANTS Database. http://plants.usda.gov.
Other references
Bunting, S.C., B.M. Kilgore, and C.L. Bushey. 1987. Guidelines for Prescribe burning sagebrush-grass rangelands in the Northern Great Basin. General Technical Report INT-231. USDA Forest Service Intermountain Research Station, Ogden, UT. 33.
Chambers, J.C., B.A. Bradley, C.S. Brown, C. D’Antonio, M.J. Germino, J.B. Grace, S.P. Hardegree, R.F. Miller, and D.A. Pyke. 2013. Resilience to Stress and Disturbance, and Resistance to Bromus tectorum L. Invasion in Cold Desert Shrublands of Western North America. Ecosystems 17:360–375.
Miller, Richard F.; Chambers, Jeanne C.; Evers, Louisa; Williams, C. Jason; Snyder, Keirith A.; Roundy, Bruce A.; Pierson, Fred B. 2019. The ecology, history, ecohydrology, and management of pinyon and juniper woodlands in the Great Basin and Northern Colorado Plateau of the western United States. Gen. Tech. Rep. RMRS-GTR-403. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 284 p.Contributors
Cici Brooks
Kyle Hansen
Jenni Moffitt, general edits and updates 2020
Andrew Neary - additional minor PES updates 2021Approval
Kirt Walstad, 4/02/2025
Acknowledgments
Original Authors: ESI Team, Burns, Oregon January 2000
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) Contact for lead author Date 02/14/2025 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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