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Conservation Service

Ecological site R023XY210OR

PUMICE 10-12 PZ

Accessed: 12/21/2024

Home / Esd catalog / MLRA 023X / Ecological site R023XY210OR

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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.

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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

R023XY221OR	GRAVELLY TERRACE 10-12 PZ Gravelly Terrace 10-12" PZ
R023XY508OR	PUMICE FLAT 10-12 PZ Pumice Flat 10-12" PZ
R023XY514OR	PUMICE 8-10 PZ Pumice 8-10" PZ

R023XY221OR

GRAVELLY TERRACE 10-12 PZ

Gravelly Terrace 10-12" PZ

R023XY508OR

PUMICE FLAT 10-12 PZ

Pumice Flat 10-12" PZ

R023XY514OR

PUMICE 8-10 PZ

Pumice 8-10" PZ

Similar sites

R023XY508OR	PUMICE FLAT 10-12 PZ Pumice Flat 10-12" PZ

R023XY508OR

PUMICE FLAT 10-12 PZ

Pumice Flat 10-12" PZ

Table 1. Dominant plant species

Tree	Not specified
Shrub	Not specified
Herbaceous	Not specified

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Physiographic features

This site occurs on nearly level to gently sloping basin and low ridges. Slopes range from 0 to 20 percent. Elevations range from 4300 to 5000 feet.

Table 2. Representative physiographic features

Landforms	(1) Ridge
Elevation	4,300 – 5,000 ft
Slope	20%
Water table depth	60 in
Aspect	Aspect is not a significant factor

Climatic features

The annual precipitation ranges from 10 to 12 inches. This occurs mainly between the months of November and June, mostly in the form of snow and spring-fall rains. The soil temperature regime is frigid. The average annual air temperature is 43 degrees F with extreme temperatures ranging from -30 to 103 degrees F. The frost free period is 50 to 90 days. The optimum period for plant growth is from mid-April through July.

Table 3. Representative climatic features

Frost-free period (average)	90 days
Freeze-free period (average)	0 days
Precipitation total (average)	12 in

Soil features

The soils of this site are very deep pumice sand and are excessively drained. They are generally underlain with mixed sand and gravel and often contain weakly cemented pans. Permeabiliity is moderately rapid and the available water holding capacity (AWC) is 7 to 10 inches for the profile. The potential for water erosion is low and for wind erosion is high.

Table 4. Representative soil features

Surface texture	(1) Gravelly sand
Family particle size	(1) Sandy
Drainage class	Excessively drained
Permeability class	Moderately rapid
Available water capacity (0-40in)	7 – 10 in

Ecological dynamics

Range in Characteristics:

Western needlegrass is more abundant where there is more coarse textured and/or gravelly pumice material.

Response to Disturbance:

Burning will temporarily reduce both big sagebrush and bitterbrush while encouraging rabbitbrush. Composition changes from overgrazing, are generally a decline in Idaho fescue and an increase in needlegrass.

State and transition model

Custom diagram

Standard diagram

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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. Historic Climax Plant Community

State 1 submodel, plant communities

1.1. Historic Climax Plant Community

State 1
Historic Climax Plant Community

Community 1.1
Historic Climax Plant Community

The potential native plant community is dominated by Idaho fescue (about 50 percent). Other prominent species include Thurber needlegrass, western needlegrass, and Ross sedge (about 5 percent each). Bitterbrush dominates the aspect (about 15 percent) and big sagebrush is also common in the stand (10 percent). Vegetative composition is approximately 70 percent grasses, 5 percent forbs, and 25 percent shrubs. Total foliar cover is about 80 percent, of which 30 percent is shrub cover, and 50 percent is grass/forb cover.

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	513	689	864
Shrub/Vine	189	243	297
Forb	45	68	90
Total	747	1000	1251

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, deep-rooted, dominant			360–540
	Idaho fescue	FEID	Festuca idahoensis	360–540	–
2	Perennial, deep-rooted, sub-dominant			135–288
	western needlegrass	ACOC3	Achnatherum occidentale	90–180	–
	Thurber's needlegrass	ACTH7	Achnatherum thurberianum	18–45	–
	Ross' sedge	CARO5	Carex rossii	18–45	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	9–18	–
4	Perennial, shallow-rooted, sub-dominant			9–18
	prairie Junegrass	KOMA	Koeleria macrantha	9–18	–
5	Other perennial grasses, all			9–18
	squirreltail	ELEL5	Elymus elymoides	0–9	–
	Sandberg bluegrass	POSE	Poa secunda	0–9	–
Forb
7	Perennial, all, dominant			36–72
	common yarrow	ACMI2	Achillea millefolium	9–18	–
	buckwheat	ERIOG	Eriogonum	9–18	–
	desertparsley	LOMAT	Lomatium	9–18	–
	lupine	LUPIN	Lupinus	9–18	–
9	Other perennial forbs, all			9–18
	pussytoes	ANTEN	Antennaria	0–4	–
	Douglas' dustymaiden	CHDO	Chaenactis douglasii	0–4	–
	common starlily	LEMO4	Leucocrinum montanum	0–4	–
	phacelia	PHACE	Phacelia	0–4	–
	phlox	PHLOX	Phlox	0–4	–
Shrub/Vine
11	Perennial, evergreen, dominant			180–270
	antelope bitterbrush	PUTR2	Purshia tridentata	135–180	–
	mountain big sagebrush	ARTRV	Artemisia tridentata ssp. vaseyana	45–90	–
15	Other perennial shrubs, all			9–27
	yellow rabbitbrush	CHVI8	Chrysothamnus viscidiflorus	0–7	–
	slender buckwheat	ERMI4	Eriogonum microthecum	0–7	–
	rubber rabbitbrush	ERNA10	Ericameria nauseosa	0–7	–

Interpretations

Animal community

Livestock Grazing:

Water is not usually available on-site. Fall-winter grazing may create a conflict with deer over the use of bitterbrush.

Native Wildlife Associated with the Potential Climax Community:

Deer
Antelope
Rabbits

Deer are important users of bitterbrush for browse.

Hydrological functions

The soils of this site have rapid infiltration rates and low runoff potential. The hydrologic soil group is C.

Other information

Adapted species for seedings include crested wheatgrass, Siberian wheatgrass, thickspike wheatgrass, and sheep fescue.

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
Contact for lead author	Oregon NRCS State Rangeland Management Specialist
Date	08/15/2012
Approved by	Bob Gillaspy
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
None, Moderate 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):
0-5%
Number of gullies and erosion associated with gullies:
None
Extent of wind scoured, blowouts and/or depositional areas:
None to some, High 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):
Slightly resistant to erosion: aggregate stability = 1-3
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Very deep excessively drained pumice sands: Low OM (0-2%)
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (70-80%) and gentle to moderate slopes (0-20%) effectively limit rainfall 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:
Idaho fescue > Western needlegrass > Antelope bitterbrush > other grasses = other shrubs > forbs

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. 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