Natural Resources
Conservation Service
Ecological site DX035X04B321
Sandstone Hills
10-14" p.z.
Last updated: 5/20/2025
Accessed: 04/14/2026
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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.
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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.
MLRA notes
Major Land Resource Area (MLRA): 035X–Colorado Plateau
This ecological site is found in Common Resource Area 35.3 – the Colorado Plateau Sagebrush – Grasslands.
The Common Resource Area occurs within the Colorado Plateau Physiographic Province. It is characterized by a sequence of flat to gently dipping sedimentary rocks eroded into plateaus, valleys and deep canyons. Elevations range from 4800 to 6700 feet and precipitation averages 10 to 14 inches. The elevation range is lower (about 4500 to 6000 ) on the western side of the Colorado Plateau along the Grand Canyon, and moves up about 500 to 800 feet higher on the eastern side in the areas of the Navajo and Hopi Indian Reservations due to rain shadow effects from the Kaibab Plateau and Mogollon Rim. Common vegetation in this region includes Wyoming big sagebrush, Utah juniper, Colorado pinyon - cliffrose, Mormon tea, fourwing saltbush, blackbrush Indian ricegrass, needle and thread, western wheatgrass Galleta, black grama, blue grama, and sand dropseed. Sedimentary rock classes dominate the plateau with volcanic fields occurring for the most part near its margin. The soil temperature regime is mesic and the soil moisture regime is ustic aridic.Ecological site concept
This site occurs on landforms such as hillslopes and plateau escarpments with slopes of 5 to 60 percent. Soils are very shallow to shallow. Surface textures are generally very channery fine sandy loam to very channery sandy clay loam.
Table 1. Dominant plant species
Tree (1) Juniperus osteosperma
Shrub (1) Purshia stansburiana
(2) Artemisia bigeloviiHerbaceous (1) Pleuraphis jamesii
(2) Achnatherum hymenoidesLegacy ID
R035XC321AZ
Physiographic features
This site occurs on various sloping landforms, such as hills and plateu escarpments. Slopes range from 5 to 60 percent.
Table 2. Representative physiographic features
Landforms (1) Hill
(2) Plateau
(3) Escarpment
Flooding frequency None Ponding frequency None Elevation 4800 – 6700 ft Slope 5 – 60 % Aspect Aspect is not a significant factor Climatic features
Winter to summer moisture ratios range from 70:30 to 60:40. Late spring is usually the driest period, 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 December through February. Accumulations above 12 inches are not common but can occur. Snow usually lasts for 3-4 days, but can persist much longer. Summer daytime temperatures are commonly 95 - 100 F and on occasion exceed 105 F. Winter air temperatures can regularly go below 10 F and have been recorded below - 20 F.
Table 3 Representative climatic features
Frost-free period (average) 170 days Freeze-free period (average) 190 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
This site occurs in an upland position. The soil moisture on this ecological site comes from precipitation. It neither benefits from run-in moisture nor sustains excessive runoff unless denuded of its vegetation.
Soil features
Soils are very shallow to shallow. Surface textures are generally very channery fine sandy loam to very channery sandy clay loam. Subsoil textures are extremely channery clay loam and very channery sandy clay loam. Parent materials are alluvium and colluvium from sedimentary rock. Geologic formation is the Mesa verde group. Available water capacity is very low. Water erosion hazard is moderate to high. Wind erosion hazard is slight. Soils are non-saline, non-sodic and mildli to moderate alkaline (pH 7.4-8.4). Soil moisture is Ustic Aridic. Soil temperature regime is Mesic.
Typical taxonomic units include:
SSA-711 Navajo Mountain Area MU 39 Reef;
SSA-713 Chinle Area MU 41 Reef;
SSA-714 Hopi Area - MU 16 Kydestea and
SSA-715 Fort Defiance Area AZ/NM - MU 53 Kydestea, MU 30 Teesto family.
Table 4. Representative soil features
Parent material (1) Alluvium – sandstone
(2) Colluvium – sandstone and shale
Surface texture (1) Very channery fine sandy loam
(2) Very channery very fine sandy loam
(3) Very channery sandy clay loam
Family particle size (1) Loamy
Drainage class Moderately well drained to well drained Permeability class Moderately slow Soil depth 5 – 20 in Surface fragment cover <=3" 0 – 45 % Surface fragment cover >3" 0 – 15 % Available water capacity
(0-40in)0 – 2.9 in Calcium carbonate equivalent
(0-40in)0 – 15 % Subsurface fragment volume <=3"
(Depth not specified)20 – 40 % Subsurface fragment volume >3"
(Depth not specified)0 – 10 % 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 fire, grazing, 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 amount shown for each group. Divide the resulting total by the total normal year production shown in the plant community description. If the rainfall has ben 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.
The State and Transition model shows the most common occurring plant communities likely to be encountered on this ecological site. This model may not show every possible plant community, but only those that are most prevalent and observed through field inventory. As more data is collected these plant communities may be revised, removed, and some added to reflect the ecological dynamics of this site.State and transition model
Custom diagramStandard diagram
Figure 4. STM - R035XC321AZ
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
State 1 submodel, plant communities
State 1
Reference StateIn aspect view this plant community is dominated by trees. Tree canopy cover is 10 - 25% with Utah juniper dominates with less amounts of Colorado pinyon..
Understory species are comprised of grasses, including galleta and Indian ricegrass, forbs such like stemless goldenweed and James cryptantha, shrubs like Stansbury cliffrose and Bigelow sagebrush.Community 1.1
Juniper/Stansbury cliffrose/Galleta
Figure 5. Sandstone Hills 10-14" p.z.
In the this plant community shrubs and trees dominate the plant community. The understory is mostly grasses with small percentage of forbs. Tree canopy ranges from 5 to 20% depending on aspects and elevations. In the understory there is a mix of cool and warm season grasses. Common shrubs include Stansbury cliffrose and Bigelow sage. At the highest elevation Wyoming big sagebrush will replace Bigelow sage.
Figure 6. 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)Shrub/Vine 75 175 250 Tree 50 150 250 Grass/Grasslike 45 100 150 Forb 15 35 50 Total 185 460 700 Table 6. Ground cover
Tree foliar cover 10-30% Shrub/vine/liana foliar cover 10-10% Grass/grasslike foliar cover 0-10% Forb foliar cover 0-0% Non-vascular plants 0% Biological crusts 0% Litter 10-20% Surface fragments >0.25" and <=3" 0-50% Surface fragments >3" 0-20% Bedrock 0% Water 0% Bare ground 20-30% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 0-2% 0-2% 0-1% >0.5 <= 1 – 0-5% 0-2% 0-1% >1 <= 2 0-1% 0-5% 0-1% 0-1% >2 <= 4.5 0-3% – – – >4.5 <= 13 5-20% – – – >13 <= 40 0-1% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 7. Plant community growth curve (percent production by month). AZ3531 , 35.3 10-14" p.z. all sites. Growth begins in the spring and continues through the summer..
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 1 3 17 18 10 19 20 10 1 1 0 Community 1.2
Juniper-Pinyon Woodland with ShrubsIn this plant community the tree canopy has increased (10-25%)and dominated by juniper with pinyon. The understory canopy of shrubs has increased and herbaceous cover has decline, especially perennial cool season grasses. Common shrubs found include Stansbury cliffrose, Bigelow sagebrush, snakeweed, rabbitbrush, big sagebrush, Torrey mormon tea and yucca.
Pathway 1.1A
Community 1.1 to 1.2Drought, improper grazing reduces perennial herbaceous cover, lack of fire.
Pathway 1.2A
Community 1.2 to 1.1Reduced tree canopy thru fire or woodcutting, Prescribed grazing or No grazing, favorable moisture/climate.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Grasses 45–150 James' galleta PLJA Pleuraphis jamesii 25–75 – Indian ricegrass ACHY Achnatherum hymenoides 15–35 – blue grama BOGR2 Bouteloua gracilis 5–25 – squirreltail ELELE Elymus elymoides ssp. elymoides 5–25 – needle and thread HECOC8 Hesperostipa comata ssp. comata 5–25 – muttongrass POFE Poa fendleriana 5–25 – alkali sacaton SPAI Sporobolus airoides 0–10 – Forb2 Forbs 15–50 Wright's bird's beak COWR2 Cordylanthus wrightii 0–10 – thrift mock goldenweed STARA Stenotus armerioides var. armerioides 0–10 – Forb, perennial 2FP Forb, perennial 0–10 – winged buckwheat ERAL4 Eriogonum alatum 0–10 – Fendler's bladderpod LEFE Lesquerella fendleri 0–5 – rock goldenrod PEPU7 Petradoria pumila 0–5 – gooseberryleaf globemallow SPGR2 Sphaeralcea grossulariifolia 0–5 – biennial wormwood ARBI2 Artemisia biennis 0–5 – milkvetch ASTRA Astragalus 0–5 – whitemargin sandmat CHAL11 Chamaesyce albomarginata 0–5 – rose heath CHER2 Chaetopappa ericoides 0–5 – desert princesplume STPI Stanleya pinnata 0–5 – James' cryptantha CRCIJ Cryptantha cinerea var. jamesii 0–5 – Brenda's yellow cryptantha CRFL5 Cryptantha flava 0–5 – Forb, annual 2FA Forb, annual 0–5 – Shrub/Vine3 Shrubs 75–250 Bigelow sage ARBI3 Artemisia bigelovii 10–40 – Stansbury cliffrose PUST Purshia stansburiana 10–40 – big sagebrush ARTR2 Artemisia tridentata 0–25 – broom snakeweed GUSA2 Gutierrezia sarothrae 5–25 – shadscale saltbush ATCO Atriplex confertifolia 0–20 – Greene's rabbitbrush CHGR6 Chrysothamnus greenei 0–20 – Shrub (>.5m) 2SHRUB Shrub (>.5m) 0–20 – Utah serviceberry AMUT Amelanchier utahensis 0–20 – black sagebrush ARNO4 Artemisia nova 0–20 – mormon tea EPVI Ephedra viridis 0–20 – crispleaf buckwheat ERCO14 Eriogonum corymbosum 0–20 – narrowleaf yucca YUAN2 Yucca angustissima 0–10 – banana yucca YUBA Yucca baccata 0–10 – Whipple cholla CYWH Cylindropuntia whipplei 0–5 – plains pricklypear OPPO Opuntia polyacantha 0–5 – Tree4 Trees 50–250 Utah juniper JUOS Juniperus osteosperma 50–200 – twoneedle pinyon PIED Pinus edulis 0–50 – Table 9. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Site is fairly suitable for grazing for cattle, sheep, goats and horses in late spring, summer and fall. Steep slopes limit livestock movement. Management consideration should be placed on proper grazing use, grazing systems and water developments.
Natural water is scarce. Mule deer use the area for winter cover. Food is adequate for most wildlife species. The area is sometimes used by grassland wildlife species.
Recreational uses
Site has a high aesthetic appeal, particularly where it borders open grasslands for contrast. Hunting, hiking, and wildlife observation are the main recreational activities.
Wood products
Equipment with rubber tires work best. Crawler tractor type equipment works best on slopes 10-25%. Tree thinning is best done by hand. Slopes over 15% limit equipment use. There are no limitations on unsurfaced roads. Some rock outcrop and stones are present. Equipment is not limited by water table/flooding.
Wind erosion is slight. Water erosion is accelerated by slopes. Compaction potential is fair as soil and channery material mix well. Soils will rut when wet. Revegation potential is poor due to shallow, droughty soils.
Harvest cutting should be limited due to low production. Prescribed burning and mechanical tree removal is not recommended. Control pests to prevent tree damage and loss. Fire hazard is low, shallow soils produce low fuel load. These areas are locally important for fuel wood harvesting.
Replanting potential is poor due to shallow soils. Seedling mortality is severe as the soil is droughty. Natural regeneration is slow, but will occur in time. Shrubs and grasses compete for moisture. There is no windthrow hazard.
Other products
These sites, where adaquate pinyon tree grow, provide areas of pinyon nut harvesting during years of good nut productions.
Supporting information
Type locality
Location 1: Navajo County, AZ General legal description John Daw Mesa, Kydestea Spring, Red Willow Spring and Owl Valley Quads on the Hopi Indian Reservation. Other references
Updates and revisions for this ESD were conducted as part of a 2007-2012 Interagency Technical Assistance Agreement between the Bureau of Indian Affairs–Navajo Region and the NRCS-Arizona.
This site was originally developed as a woodland site (F035XC321AZ). These sites are not forestland sites, but are rangeland ecological sites.Contributors
Ken Gishi
Approval
Kendra Moseley, 5/20/2025
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) Kenneth Gishi Contact for lead author State Rangeland Management Specialist, NRCS-Arizona State Office, Phoenix, AZ Date 09/19/2012 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
Rills may be common on steepest slopes due to high amount of rock outcrop directing runoff onto soils and low potential to support vegetative growth on shallow and very shallow soils. -
Presence of water flow patterns:
Water flow patterns may be common on the steepest slopes due to high amount of rock outcrop directing runoff onto the soils and low potential for supporting vegetative growth on the shallow and very shallow soils. These patterns are short and discontinuous across larger soil areas, but may be longer and more continuous where soils lie adjacent to bedrock. -
Number and height of erosional pedestals or terracettes:
Pedestals and terracettes may be common due to the slopes and moderate potential for water erosion. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground ranges from 15 to 25 percent. -
Number of gullies and erosion associated with gullies:
Few are expected. When site is well vegetated and covered with rock fragments gullies are stablilzed with vegetation, shallow and will only show minor signs of active erosion. -
Extent of wind scoured, blowouts and/or depositional areas:
Wind scour and blowouts are not expected on this site. There may be some deposition around large shrubs and trees. -
Amount of litter movement (describe size and distance expected to travel):
Herbaceous and fine woody litter will be transorted in water flow pathways and by wind. Coarse woody litter will remain under shrub and tree canopies. Litter movement may be greatest in areas of steep slopes or areas adjacent to rock outcrop. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
The expected average soil stability is 2. Surface fragments, litter, and vegetation cover aid in reducing erosion. This site has moderate resistance to wind erosion and low resistance to water erosion. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil surface structures are waek platy (thin, fine to moderate) parting to medium granular structure. Surface thickness of the A-horizon is 1-3 inches. Color of the A-horizon does not differ significatly from the subsurface soil horizons. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
This site is characterized by a relatively even distribution of perennial grasses with scattered half-shrubs, large shrubs, forbs and scattered trees. The vegetation when well distributed along with rock fragments across the site lends to slowing runoff and allowing for some infiltration. Steep slopes and areas of rock outcrops lends to high runoff on this site. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. These soils are shallow with rock fragments. -
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:
Shrubs (large and low shrubs) >Sub-dominant:
Trees > cool season grasses > warm season grasses >Other:
Forbs > cacti & succulentsAdditional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
All plant functional groups are adapted to survival in all but the most severe droughts. Severe winter droughts affect the shrubs the most. Severe summer droughts affect grasses the most. -
Average percent litter cover (%) and depth ( in):
Litter size and depth on this size will vary greatly beneath tree canopies and the platn interspaces. Litter size will range from 1 leaf thickness to woody litter 3 inches in diameter. Litter will be the highest under tree canopies with a mix of herbaceous, duff and woody litter. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Average annual production on this site is expected to be 400 to 500 lbs/ac. in a year of average annual precipitation. -
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:
Juniper, broom snakeweed and rabbitbrush are all native to the site, but may have the potential to increase with continued disturbance. Cheatgrass and Russian thistle are non-native annuals that have the potential to invade the site with or without disturbance. -
Perennial plant reproductive capability:
All plants native to the site are adapted to the climate and are capable of producing seeds, stolons, and/or rhizomes during the most severe droughts.
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