Natural Resources
Conservation Service

Ecological site R010XA018OR

Juniper Shrubby Loam
10-12 PZ

Last updated: 5/06/2025
Accessed: 04/20/2026

Home / esd CATALOG / MLRA 010X / ecological site R010XA018OR

USC

Metric

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.

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.

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 averaging8 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.

Associated sites

R010XA009OR	Juniper Shrubby Pumice Flat 10-12 PZ

R010XA009OR

Juniper Shrubby Pumice Flat 10-12 PZ

Similar sites

R010XA019OR	Shrubby Loam 8-12 PZ
R010XA001OR	Loamy 8-10 PZ

R010XA019OR

Shrubby Loam 8-12 PZ

R010XA001OR

Loamy 8-10 PZ

Table 1. Dominant plant species

Tree	(1) Juniperus occidentalis
Shrub	(1) Purshia tridentata (2) Artemisia tridentata
Herbaceous	(1) Pseudoroegneria spicata ssp. spicata (2) Festuca idahoensis

Download full description

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	2000 – 4000 ft
Slope	0 – 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)
Precipitation total (average)	10 in

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

Custom diagram

Standard 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 text

Ecosystem states

1. Reference

State 1 submodel, plant communities

1.1. Reference Plant Community

State 1
Reference

Community 1.1
Reference 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	510	650	800
Shrub/Vine	125	165	200
Tree	50	65	75
Forb	15	20	25
Total	700	900	1100

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 ()	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
	thickspike wheatgrass	ELLA3	Elymus lanceolatus	0–9	–
	prairie Junegrass	KOMA	Koeleria macrantha	0–9	–
	basin wildrye	LECI4	Leymus cinereus	0–9	–
	Cusick's bluegrass	POCU3	Poa cusickii	0–9	–
Forb
9	All other perennial forbs			9–36
	common yarrow	ACMI2	Achillea millefolium	0–9	–
	agoseris	AGOSE	Agoseris	0–9	–
	pussytoes	ANTEN	Antennaria	0–9	–
	Palouse milkvetch	ASAR7	Astragalus arrectus	0–9	–
	Idaho milkvetch	ASCO11	Astragalus conjunctus	0–9	–
	woollypod milkvetch	ASPU9	Astragalus purshii	0–9	–
	arrowleaf balsamroot	BASA3	Balsamorhiza sagittata	0–9	–
	fleabane	ERIGE2	Erigeron	0–9	–
	desertparsley	LOMAT	Lomatium	0–9	–
	phacelia	PHACE	Phacelia	0–9	–
	spreading phlox	PHDI3	Phlox diffusa	0–9	–
	salsify	TRPO	Tragopogon porrifolius	0–9	–
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	0–9	–
	snow buckwheat	ERNI2	Eriogonum niveum	0–9	–
	wax currant	RICE	Ribes cereum	0–9	–
	desert gooseberry	RIVE	Ribes velutinum	0–9	–
	spineless horsebrush	TECA2	Tetradymia canescens	0–9	–
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.

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
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 shrubs

Sub-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

Download reference sheet

Natural ResourcesConservation Service