Natural Resources
Conservation Service
Ecological site R023XY508OR
PUMICE FLAT 10-12 PZ
Accessed: 11/21/2024
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.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Artemisia tridentata ssp. vaseyana |
| Herbaceous |
(1) Stipa occidentalis |
Physiographic features
This site occurs on nearly level to gently sloping areas within basins. Slopes range from nearly flat to 5 percent. Elevations range from 4,300 to 5,000 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Lava plain
(2) Lake terrace (3) Lava plateau |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 396 – 1,524 m |
| Slope | 0 – 5% |
| 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 November and June, mostly in the form of snow and spring-fall rains. The soil temperature regime is frigid. The 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 early July.
Table 3. Representative climatic features
| Frost-free period (average) | 90 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 305 mm |
Figure 2. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils of this site are moderately deep to very deep and well to somewhat excessively drained. They are generally formed from volcanic ash over residuum or alluvium. Permeability is moderately slow and the available water holding capacity (AWC) is 6.0 to 10.0 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 loamy sand (2) Ashy loamy sand (3) Gravelly coarse sand |
|---|---|
| Family particle size |
(1) Sandy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderate to rapid |
| Soil depth | 51 – 152 cm |
| Surface fragment cover <=3" | 15 – 40% |
| Surface fragment cover >3" | 0 – 5% |
| Available water capacity (0-101.6cm) |
3.3 – 20.07 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0% |
| Electrical conductivity (0-101.6cm) |
0 – 2 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 |
| Soil reaction (1:1 water) (0-101.6cm) |
6.6 – 7.8 |
| Subsurface fragment volume <=3" (Depth not specified) |
6 – 35% |
| Subsurface fragment volume >3" (Depth not specified) |
0 – 7% |
Ecological dynamics
Areas with greater amounts of gravel and coarse textured soil will have more needlegrass. Other areas higher in ash with less coarse material support greater amounts of Idaho fescue and less needlegrass.
With overgrazing by cattle, Junegrass, Thurber needlegrass, and Ross sedge can be reduced or eliminated from the stand. Burning reduces cover of sagebrush and increases rabbitbrush.
Cheatgrass, gray rabbitbrush, annual phlox, and collinsia may invade this site.
State and transition model
More interactive model formats are also available.
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference Plant Community
Community 1.1
Reference Plant Community
The reference native plant community is dominated by big sagebrush and western needlegrass. Ross sedge, squirreltail, buckwheat, and green rabbitbrush are also common in the stand. Vegetative composition is approximately 65% grasses, 5% forbs, and 30% shrubs.
Figure 3. 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 | 291 | 364 | 437 |
| Shrub/Vine | 135 | 168 | 202 |
| Forb | 22 | 28 | 34 |
| Total | 448 | 560 | 673 |
Table 6. Canopy structure (% cover)
| Height Above Ground (m) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.15 | – | 0-2% | – | – |
| >0.15 <= 0.3 | – | – | 5-10% | 0-2% |
| >0.3 <= 0.6 | – | – | 30-35% | 0-3% |
| >0.6 <= 1.4 | – | 10-15% | – | – |
| >1.4 <= 4 | – | – | – | – |
| >4 <= 12 | – | – | – | – |
| >12 <= 24 | – | – | – | – |
| >24 <= 37 | – | – | – | – |
| >37 | – | – | – | – |
Additional community tables
Table 7. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Perennial, bunch grass, deep-rooted | 168–280 | ||||
| western needlegrass | ACOCO | Achnatherum occidentale ssp. occidentale | 168–280 | – | ||
| 2 | Upland sedge | 56–84 | ||||
| Ross' sedge | CARO5 | Carex rossii | 56–84 | – | ||
| 3 | Perennial, bunch-grass, moderately deep-rooted | 28–56 | ||||
| squirreltail | ELEL5 | Elymus elymoides | 28–39 | – | ||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 11–28 | – | ||
| 4 | Perennial, rhizomatous | 6–11 | ||||
| thickspike wheatgrass | ELLA3 | Elymus lanceolatus | 6–11 | – | ||
| 8 | Other perennial grasses | 6–11 | ||||
| sedge | CAREX | Carex | 0–6 | – | ||
| Idaho fescue | FEID | Festuca idahoensis | 0–6 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–6 | – | ||
| mat muhly | MURI | Muhlenbergia richardsonis | 0–6 | – | ||
|
Forb
|
||||||
| 10 | Perennial forb | 6–11 | ||||
| buckwheat | ERIOG | Eriogonum | 6–11 | – | ||
| 15 | Other perennial forbs | 6–11 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–6 | – | ||
| western pearly everlasting | ANMA | Anaphalis margaritacea | 0–6 | – | ||
| pussytoes | ANTEN | Antennaria | 0–6 | – | ||
| rockcress | ARABI2 | Arabis | 0–6 | – | ||
| woollypod milkvetch | ASPU9 | Astragalus purshii | 0–6 | – | ||
| Indian paintbrush | CASTI2 | Castilleja | 0–6 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–6 | – | ||
| starlily | LEUCO | Leucocrinum | 0–6 | – | ||
| Lewis flax | LILE3 | Linum lewisii | 0–6 | – | ||
| lupine | LUPIN | Lupinus | 0–6 | – | ||
|
Shrub/Vine
|
||||||
| 20 | Evergreen | 112–140 | ||||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 112–140 | – | ||
| 21 | Evergreen | 22–34 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 22–34 | – | ||
| 22 | Sub-shrub | 0–6 | ||||
| granite prickly phlox | LIPU11 | Linanthus pungens | 0–6 | – | ||
Interpretations
Animal community
Winter grazing is possible in mild winters with little snow. Protection from cold is limited due to limited tall cover.
Wildlife include Pronghorn Antelope, Mule Deer, and various rodents.
Hydrological functions
Natural water is not usually available on this site.
The soils of this site have high infiltration rates and low runoff potential.
Other information
Adapted species for seedings include crested wheatgrass, Siberian wheatgrass, and thickspike wheatgrass.
Supporting information
Contributors
Gene Hickman
Justin Gredvig
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 | |
| Approved by | |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
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:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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 plant reproductive capability:
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