Natural Resources
Conservation Service
Ecological site R035XI905AZ
Loamy Upland 25-33" p.z.
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.
MLRA notes
Major Land Resource Area (MLRA): 035X–Colorado Plateau
AZ CRA 35.9 - Colorado Plateau Coniferous Forests
Elevations range from 8000 to 9700 feet and precipitation averages 25 to 33 inches per year. Vegetation includes white fir, ponderosa pine, quaking aspen, Engelmann spruce, subalpine fir ,Douglas fir, Blue spruce , muttongrass, upland sedge, big wildrye, redroot buckwheat, creeping mahonia, dwarf juniper, mat muhly, mountain muhly, needlegrasses, and alpine timothy. The soil temperature regime is frigid and the soil moisture regime is udic ustic. This unit occurs within the Colorado Plateau Physiographic Province and is characterized by a sequence of flat to gently dipping sedimentary rocks eroded into plateaus, valleys and deep canyons. Sedimentary rock classes dominate the plateau with volcanic fields occurring for the most part near its margin.
Associated sites
| F035XI902AZ |
Loamy Hills 25-33" p.z. (ABCO, PIPO, POTR5) |
|---|---|
| F035XI903AZ |
Loamy Hills 25-33" p.z. Cold (ABLA, PIEN) |
Similar sites
| R035XI904AZ |
Loamy Bottom 25-33" p.z. Subirrigated |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
(1) Muhlenbergia montana |
Physiographic features
This site occurs on the deep and very deep soils of the valleys and fan terraces along the wider drainageways that separate the plateaus and hills. Surface soil textures are sandy loam and loam, sometimes gravelly. Slope range is typically 1 to 8 percent, but can be as high as 15 percent. The site occurs on all aspects, and it may contain small inclusions of shallow soils and rock outcrop.
Table 2. Representative physiographic features
| Landforms |
(1)
Plateau
(2) Valley (3) Fan |
|---|---|
| Flooding duration | Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours) |
| Flooding frequency | None to very rare |
| Ponding frequency | None |
| Elevation | 2,195 – 2,865 m |
| Slope | 1 – 15% |
| Aspect | Aspect is not a significant factor |
Climatic features
Winter-Summer moisture ratios are typically 70:30. Late spring and summer is usually the driest periods and early fall moisture can be sporadic. Summer rains fall from June through September; moisture originates in the Gulf of Mexico and creates convective, usually brief, intense thunderstorms. Cool season moisture from October through May tends to be frontal; it originates in the Pacific and the Gulf of California and falls in widespread storms with longer duration and lower intensity. Precipitation generally comes as snow from October into April. Snow pack can persist for 3-4 months, although it may disappear in exposed areas during prolonged dry weather. Summer daytime temperatures are typically 60-70 F but rarely exceed 80 F. Winter temperatures around 10 F are common and can reach -10 F.
Table 3. Representative climatic features
| Frost-free period (average) | 90 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 838 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils on this site are typically deep and very deep, with occasional inclusions of moderate depth. Surface gravel content usually ranges from 2 to 5 percent and is occasionally as high as 20 percent. Most soils have a mollic epipedon that is 16 or more inches thick. Surface soil textures are sandy loam and loam; subsurface textures are mainly loam or sandy loam throughout the profile but may become clay loam to clayey below about 30 inches.
Table 4. Representative soil features
| Surface texture |
(1) Gravelly loam (2) Gravelly sandy loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Moderately well drained to well drained |
| Permeability class | Moderate to moderately rapid |
| Soil depth | 102 – 152 cm |
| Surface fragment cover <=3" | 10 – 20% |
| Available water capacity (0-101.6cm) |
12.7 – 25.4 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0 – 2% |
| Electrical conductivity (0-101.6cm) |
0 – 2 mmhos/cm |
| Soil reaction (1:1 water) (0-101.6cm) |
5.8 – 7.1 |
Ecological dynamics
The plant communities found on an ecological site are naturally variable. Composition and production will vary with yearly conditions, location, aspect, and the natural variability of the soils. The historical climax plant community represents the natural potential plant communities found on relict or relatively undisturbed sites. Other plant communities described here represent plant communities that are known to occur when the site is disturbed by factors such as grazing, fire, or drought.
Production data provided in this site description is standardized to air-dry weight at the end of the summer growing season. The plant communities described in this site description are based on near normal rainfall years.
NRCS uses a Similarity Index to compare existing plant communities to the plant communities described here. Similarity Index is determined by comparing the production and composition of a plant community to the production and composition of a plant community described in this site description. To determine Similarity Index, compare the production (air-dry weight) of each species to that shown in the plant community description. For each species, count no more than the maximum amount shown for the species, and for each group, count no more than the maximum shown for the group. Divide the resulting total by the total normal year production shown in the plant community description. If rainfall has been significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant Community
Community 1.1
Historic Climax Plant Community
This is a draft site. This site developed under historic Colorado Plateau conditions, and reflects the natural influences of herbivores, climate fluctuations, and occasional fire. This state includes the native plant communities that occurred on the site prior to European immigration and settlement. This community is a grass/forb site with a great deal of species diversity, especially with regard to perennial and annual forbs. Shrubs and sub-shrubs are infrequent. In the prolonged absence of fire, trees will encroach on this site areound the edges, especially quaking aspen and blue and Engelmann spruce. terraces along the narrower drainageways between the forested hills, which were historically open, may become forested themselves.
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 | 555 | 681 | 807 |
| Forb | 202 | 278 | 353 |
| Total | 757 | 959 | 1160 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 0% |
| Grass/grasslike foliar cover | 30-40% |
| Forb foliar cover | 10-20% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 0% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 0% |
Figure 5. Plant community growth curve (percent production by month). AZ3591, 35.9 25-33" p.z. all sites. Growth begins in late spring and continues into the fall..
| 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 | 0 | 0 | 15 | 15 | 20 | 25 | 20 | 5 | 0 | 0 |
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 Dominant Native | 151–303 | ||||
| mountain muhly | MUMO | Muhlenbergia montana | 151–303 | – | ||
| 2 | Common Native Mid Grasses | 101–252 | ||||
| pine dropseed | BLTR | Blepharoneuron tricholepis | 50–151 | – | ||
| sedge | CAREX | Carex | 50–151 | – | ||
| 3 | Occasional Native Summer Perennial | 11–50 | ||||
| Grass, perennial | 2GP | Grass, perennial | 0–22 | – | ||
| rough bentgrass | AGSC5 | Agrostis scabra | 0–11 | – | ||
| timber oatgrass | DAIN | Danthonia intermedia | 0–11 | – | ||
| slimstem muhly | MUFI | Muhlenbergia filiculmis | 0–11 | – | ||
| creeping muhly | MURE | Muhlenbergia repens | 0–11 | – | ||
| mat muhly | MURI | Muhlenbergia richardsonis | 0–11 | – | ||
| spike muhly | MUWR | Muhlenbergia wrightii | 0–11 | – | ||
| 4 | Occasional Native Spring Perennial | 50–252 | ||||
| Porter brome | BRPO2 | Bromus porteri | 0–50 | – | ||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 0–50 | – | ||
| big squirreltail | ELMU3 | Elymus multisetus | 0–50 | – | ||
| Arizona fescue | FEAR2 | Festuca arizonica | 0–50 | – | ||
| sheep fescue | FEOV | Festuca ovina | 0–50 | – | ||
| muttongrass | POFE | Poa fendleriana | 0–50 | – | ||
| Letterman's needlegrass | ACLE9 | Achnatherum lettermanii | 0–34 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–34 | – | ||
| Grass, perennial | 2GP | Grass, perennial | 0–22 | – | ||
| western wheatgrass | PASM | Pascopyrum smithii | 0–11 | – | ||
| Canada bluegrass | POCO | Poa compressa | 0–11 | – | ||
| blue wildrye | ELGL | Elymus glaucus | 0–11 | – | ||
| Canada wildrye | ELCA4 | Elymus canadensis | 0–11 | – | ||
|
Forb
|
||||||
| 5 | Common Native Perennial Short Forbs | 50–101 | ||||
| white sagebrush | ARLU | Artemisia ludoviciana | 6–50 | – | ||
| redroot buckwheat | ERRA3 | Eriogonum racemosum | 6–50 | – | ||
| aspen fleabane | ERSPM | Erigeron speciosus var. macranthus | 6–50 | – | ||
| 6 | Occasional Native Perennial Short Forbs | 50–151 | ||||
| Forb, perennial | 2FP | Forb, perennial | 0–34 | – | ||
| western yarrow | ACMIO | Achillea millefolium var. occidentalis | 0–34 | – | ||
| pussytoes | ANTEN | Antennaria | 0–34 | – | ||
| Fendler's sandwort | ARFE3 | Arenaria fendleri | 0–34 | – | ||
| Indian paintbrush | CASTI2 | Castilleja | 0–34 | – | ||
| Wheeler's thistle | CIWH | Cirsium wheeleri | 0–34 | – | ||
| chaparral fleabane | EROR5 | Erigeron oreophilus | 0–34 | – | ||
| gentian | GENTI | Gentiana | 0–34 | – | ||
| showy goldeneye | HEMU3 | Heliomeris multiflora | 0–34 | – | ||
| hairy false goldenaster | HEVIM3 | Heterotheca villosa var. minor | 0–34 | – | ||
| pygmy bluet | HOWR | Houstonia wrightii | 0–34 | – | ||
| lupine | LUPIN | Lupinus | 0–34 | – | ||
| cinquefoil | POTEN | Potentilla | 0–34 | – | ||
| goldenweed | PYRRO | Pyrrocoma | 0–34 | – | ||
| heartleaf buttercup | RACA4 | Ranunculus cardiophyllus | 0–34 | – | ||
| Macoun's buttercup | RAMA2 | Ranunculus macounii | 0–34 | – | ||
| Mt. Albert goldenrod | SOSI3 | Solidago simplex | 0–34 | – | ||
| alpine leafybract aster | SYFO2 | Symphyotrichum foliaceum | 0–34 | – | ||
| 7 | Occasional Native Annual Short Forbs | 11–101 | ||||
| Forb, annual | 2FA | Forb, annual | 0–20 | – | ||
| trailing fleabane | ERFL | Erigeron flagellaris | 0–20 | – | ||
| Cooper's rubberweed | HYCO2 | Hymenoxys cooperi | 0–20 | – | ||
| fineleaf hymenopappus | HYFI | Hymenopappus filifolius | 0–20 | – | ||
| scarlet gilia | IPAG | Ipomopsis aggregata | 0–20 | – | ||
| yellow owl's-clover | ORLU2 | Orthocarpus luteus | 0–20 | – | ||
| purplewhite owl's-clover | ORPU2 | Orthocarpus purpureoalbus | 0–20 | – | ||
| sticky polemonium | POVI | Polemonium viscosum | 0–20 | – | ||
| white prairie aster | SYFAC | Symphyotrichum falcatum var. commutatum | 0–20 | – | ||
Interpretations
Animal community
This site is suitable for grazing by all classes of livestock. The site is used primarily as late spring to early fall seasonal range. When grazed with sites with less accessibility and productivity it normally becomes a key management area.
This site has relatively poor habitat diversity in the native plant community. It is primarily adapted to grassland wildlife species except at the edge of timber where it is utilized by many species. Large game animals are migratory onto the site primarily for summer use.
Recreational uses
This site has a variety of summer flowers. Its open grassland which abruptly joins the timber edge makes the site aesthetically pleasing. Summers are cool and pleasant but winters are harsh and cold.
Activities for which this site is suited include hunting, camping, wildlife observation and photography.
Supporting information
Type locality
| Location 1: Coconino County, AZ | |
|---|---|
| General legal description | Approximately 10 miles south of Jacobs Lake, AZ |
Contributors
Larry D. Ellicott
Steve Barker
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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