Natural Resources
Conservation Service
Ecological site DX035X03B812
Sandy Upland
17-25" p.z.
(PIPO)
Last updated: 5/20/2025
Accessed: 04/30/2026
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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 occurs in Common Resource Area 35.8 - the Colorado Plateau Ponderosa Pine Forests
The Common Resource Area occurs within the Colorado Plateau Physiographic Province. Elevations range from 6800 to 8500 feet and precipitation averages 17 to 25 inches per year. Vegetation includes ponderosa pine, white fir, aspen, pinyon, juniper, Gambel oak, big sagebrush, ceanothus, blue elderberry, muttongrass, upland sedge, and big wildrye, mountain muhly, Arizona fescue, pine dropseed, and blue grama. The soil temperature regime ranges from mesic to frigid and the soil moisture regime is typic 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.Ecological site concept
Soils grouped in this site are moderately deep to very deep. Surface textures range from loamy fine sand to fine sandy loam. Parent material is alluvium from sandstone and basalt. This ecological site occurs on fan terraces and toeslopes of stable landslides, mountains and plateaus. Slopes are generally 0 to 15 percent, but may be slightly steeper in spots. The site does not benefit significantly from run-on moisture from other sites.
Table 1. Dominant plant species
Tree (1) Pinus ponderosa
(2) Pseudotsuga menziesiiShrub (1) Quercus gambelii
(2) Ceanothus fendleriHerbaceous (1) Carex geophila
(2) Lupinus argenteusLegacy ID
F035XH812AZ
Physiographic features
This site occurs on fan terraces and toeslopes of stable landslides, mountains and plateaus. Slopes are generally 0 to 15 percent, but may be slightly steeper in spots. The soils are deep. Surface textures range from loamy fine sand to fine sandy loam. The site does not benefit significantly from run-on moisture from other sites.
Table 2. Representative physiographic features
Landforms (1) Fan
(2) Plateau
(3) Structural bench
Flooding frequency None Ponding frequency None Elevation 7600 – 8500 ft Slope 0 – 15 % Aspect Aspect is not a significant factor Climatic features
Winter-Summer moisture ratios are typically 70:30 on the west side of this CRA and shift to 60:40 on the east side. 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 October into April. Snowpack can persist for 3-4 months, although it may disappear in exposed areas during prolonged dry weather. Summer daytime temperatures are typically 80-90 F but can exceed 95 F. Winter temperatures around 0 F are common and can reach -25 F.
Table 3 Representative climatic features
Frost-free period (average) 100 days Freeze-free period (average) 130 days Precipitation total (average) 30 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.
Soil features
Soils are moderatly deep to very deep. Surface textures range from loamy fine sand to fine sandy loam. Subsurface textures range from loamy fine sand to fine sandy loam. Parent material is alluvium from sandstone and basalt.
Water erosion hazard is slight to moderate; wind erosion is very high to high. Soils are non-saline, non-sodic. pH range is 5.6-7.3. Available water capacity is very low to very high. Soil moisture regime is typic ustic; temperature regime is frigid.
Soil survey map unit components that have been correlated to this ecological site include;
SSA-713 Chinle Area MU 59-Typic Ustipsamments;
SSA-715 Ft. Defiance Area NM/AZ 51-Sandark family;
SSA-717 Shiprock Area AZ/NM MU's 604 & 606 Sandark.Table 4. Representative soil features
Parent material (1) Alluvium – sandstone
(2) Residuum – basalt
Surface texture (1) Loamy fine sand
(2) Sand
(3) Fine sandy loam
Family particle size (1) Sandy
Drainage class Somewhat excessively drained to excessively drained Permeability class Moderately slow to rapid Soil depth 40 – 80 in Surface fragment cover <=3" 0 – 10 % Available water capacity
(0-40in)2 – 10 in Soil reaction (1:1 water)
(0-40in)5.6 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)0 – 10 % Ecological dynamics
An ecological site is not a precise assemblage of species for which the proportions are the same from place to place or from year to year. In all plant communities, variability is apparent in productivity and occurrence of individual species. Spatial boundaries of the communities; however, can be recognized by characteristic patterns of species composition, association, and community structure. The historic climax plant community for this ecological site has been described by sampling relict or relatively undisturbed sites and/or reviewing historic records. The historic climax plant community is the plant community that evolved over time with the soil forming process and long term changes in climatic conditions of the area. It is the plant community that was best adapted to the unique combination of environmental factors associated with the site.
Natural disturbances, such as drought, fire, grazing of native fauna, and insects, are inherent in the development and maintenance of these plant communities. The effects of these disturbances are part of the range of characteristics of the ecological site. Fluctuations in plant community structure and function caused by the effects of natural disturbances help establish the boundaries and characteristics of an ecological site. They are accounted for as part of the range of characteristics of the ecological site. Recognizable plant community phases are identified in the reference state of the ecological site. Some sites may have a small range of variation, while others have a large range. Some plant community phases may exist for long periods of time, while others may only occur for a couple of years after a disturbance.
Deterioration of the plant community, hydrology, or soil site stability on an ecological site can result in crossing a threshold or potentially irreversible boundary to another state, or equilibrium. This can occur as a result of the loss of soil surface through erosion, the loss of the stability of the site due to disturbances that cause active erosion on the site, increases in the amounts and/or patterns or runoff from rainstorms, changes in availability of surface and subsurface water, significant changes in plant structural and functional types, or the introduction of non-native species. When these thresholds are crossed, the potential of the ecological site to return to the historic climax plant community can be lost, or restoration will require significant inputs . There may be multiple states possible for an ecological site, determined by the type and or severity of disturbance.
The known states and transition pathways for this ecological site are described in the state and transition model. Within each state, there may be one or more known plant community phases. These community phases describe the different plant community that can be recognized and mapped across this ecological site. The state and transition model is intended to help land users recognize the current plant community on the ecological site, and the management options for improving the plant community to the desired plant community.
Plant production information in this site description is standardized to the annual production on an air-dry weight basis in near normal rainfall years.
State and transition model
Custom diagramStandard diagram
Figure 4. 358 SandyUpland S&T
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 2 submodel, plant communities
State 1
Reference StateThis site has a potential tree canopy cover of 65-75% dominated by ponderosa pine with a mix of Douglas fir and quaking aspen. Other tree species present in minor amounts include Gambel oak, Rocky Mountain juniper and Colorado pinyon pine. Common herbaceous species include White Mountain sedge, nodding brome, squirreltail, needle and thread, silvery lupine, western brackenfern and geranium. Low woody species present in small amounts include creeping barberry, Navajo yucca, kinnikinnick, Fendler ceanothus and short Gambel oaks. At higher elevations quaking aspen and Douglas fir will increase in canopy cover along with kinnikinnick and common juniper.
Community 1.1
Historic Cllimax Plant CommunityThis plant community has a tree canopy cover of 65-75%, with an understory comprised mainly of grasses and forbs, with a few scattered shrubs and short trees. The main tree stand in dominated by ponderosa pine with the secondary stand of Douglas fir and quaking aspen.
Figure 5. 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 150 220 310 Forb 120 175 245 Tree 105 155 215 Shrub/Vine 30 65 95 Total 405 615 865 Figure 6. Plant community growth curve (percent production by month). AZ3581 , 35.8 17-25" p.z. all sites. Growth begins in the spring, most growth occurs during the summer rainy season..
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 4 10 24 21 23 13 5 0 0 Community 1.2
Severely reduced PIPO overstory1 to 10% canopy, with 10 to 20% cover in shorter trees.
Dense and abundant grass and forb cover.Community 1.3
Short dense PIPO OverstoryPole sized PIPO with very dense overstory
Dense upper and lower canopies (50-60%) sparse understoryPathway 1.1
Community 1.1 to 1.2Partial removal of mature PIPO canopy through timber harvest, or bark beetle infestation with drought. The reduced canopy results in higher production on the forest floor of grass, forb and to some extent shrubs.
Conservation practices
Forage Harvest Management Forest Land Management Pathway 1.2
Community 1.1 to 1.3Openings are filled in by natural regeneration of ponderosa pine through favorable wet climate, forming an even aged tight canopy of sapling to pole size ponderosa pine.
Pathway 1.2
Community 1.2 to 1.3Openings are filled in by natural regeneration of ponderosa pine, forming an even aged tight canopy of sapling to pole size ponderosa pine
Pathway 1.3
Community 1.3 to 1.1Trees mature and are thinned either naturally or through pre-commercial forest thinning forming a mature canopy.
Conservation practices
Forest Stand Improvement Forest Land Management Pathway 1.4
Community 1.3 to 1.2Trees mature and are thinned more heavily than 1.3 plant community, through nature fire or timber harvest (thinning) forming a patchy and mature canopy.
Conservation practices
Forest Stand Improvement Forest Land Management State 2
Canopy removed Grass and Forb DominatedCommunity 2.1
Canopy removed Grass and Forb DominatedLess than 5% canopy remains site is dominated by grasses and forbs with inadequate tree regeneration.
Transition 1
State 1 to 2Catastrophic wildfire event removes the majority of overstory.
Restoration pathway 1
State 2 to 1Tree planting and forest management
Conservation practices
Agroforestry Planting Forest Land Management Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Common Perennial Grasses/Grasslikes 123–185 nodding brome BRAN Bromus anomalus 31–92 – White Mountain sedge CAGE Carex geophila 31–92 – squirreltail ELEL5 Elymus elymoides 31–62 – Arizona fescue FEAR2 Festuca arizonica 6–62 – needle and thread HECO26 Hesperostipa comata 6–62 – 2 Ocassional Perennial Grasses 31–62 pine dropseed BLTR Blepharoneuron tricholepis 0–31 – prairie Junegrass KOMA Koeleria macrantha 0–31 – mountain muhly MUMO Muhlenbergia montana 0–31 – muttongrass POFE Poa fendleriana 0–31 – western wheatgrass PASM Pascopyrum smithii 0–18 – blue grama BOGR2 Bouteloua gracilis 0–18 – 3 Others Grasses 0–18 Grass, perennial 2GP Grass, perennial 0–18 – Grass, annual 2GA Grass, annual 0–12 – Forb4 Common Forbs 125–185 silvery lupine LUAR3 Lupinus argenteus 31–62 – hairy brackenfern PTAQP2 Pteridium aquilinum var. pubescens 31–62 – New Mexico groundsel PANE7 Packera neomexicana 0–31 – woodland strawberry FRVEB2 Fragaria vesca ssp. bracteata 0–31 – pineywoods geranium GECA3 Geranium caespitosum 0–31 – 5 Occasional Forbs 31–62 western yarrow ACMIO Achillea millefolium var. occidentalis 0–18 – pussytoes ANTEN Antennaria 0–18 – ragleaf bahia BADI Bahia dissecta 0–18 – winged buckwheat ERAL4 Eriogonum alatum 0–18 – pingue rubberweed HYRI Hymenoxys richardsonii 0–18 – scarlet gilia IPAG Ipomopsis aggregata 0–12 – Wright's deervetch LOWR Lotus wrightii 0–12 – wild bergamot MOFI Monarda fistulosa 0–12 – catchfly SILEN Silene 0–12 – Mt. Albert goldenrod SOSI3 Solidago simplex 0–12 – Forb, perennial 2FP Forb, perennial 0–12 – sanddune wallflower ERCA14 Erysimum capitatum 0–12 – trailing fleabane ERFL Erigeron flagellaris 0–12 – aspen fleabane ERSP4 Erigeron speciosus 0–12 – yellow hawkweed HIFE Hieracium fendleri 0–12 – Mexican woollywhite HYME Hymenopappus mexicanus 0–12 – James' cryptantha CRCI3 Cryptantha cinerea 0–12 – Carruth's sagewort ARCA14 Artemisia carruthii 0–12 – tarragon ARDR4 Artemisia dracunculus 0–12 – Fendler's sandwort ARFE3 Arenaria fendleri 0–12 – Forb, annual 2FA Forb, annual 0–6 – Shrub/Vine6 Shrubs 31–92 kinnikinnick ARUV Arctostaphylos uva-ursi 0–31 – Fendler's ceanothus CEFE Ceanothus fendleri 0–31 – creeping barberry MARE11 Mahonia repens 0–31 – alderleaf mountain mahogany CEMO2 Cercocarpus montanus 0–18 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–18 – hairy false goldenaster HEVI4 Heterotheca villosa 0–18 – common juniper JUCO6 Juniperus communis 0–18 – Forb, perennial 2FP Forb, perennial 0–18 – Shrub (>.5m) 2SHRUB Shrub (>.5m) 0–12 – Subshrub (<.5m) 2SUBS Subshrub (<.5m) 0–12 – Forb, annual 2FA Forb, annual 0–12 – Navajo yucca YUBA2 Yucca baileyi 0–12 – Tree7 Trees (<4.5') 123–185 Gambel oak QUGA Quercus gambelii 92–154 – twoneedle pinyon PIED Pinus edulis 0–31 – ponderosa pine PIPO Pinus ponderosa 0–31 – quaking aspen POTR5 Populus tremuloides 0–31 – Douglas-fir PSME Pseudotsuga menziesii 0–31 – Table 7. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 1.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Site is suitable for grazing by cattle, sheep, goats and horses during summer or early fall before the tree canopy exceeds 50%.
Management considerations include grazing systems, proper grazing, and avoiding livestock concentrations that would denude the vegetation exposing the soil to erosion. Grazing should not damage young trees.
Water is found in scattered springs or man-made watering facilities. Cover for wildlife is good for most species. Food has good potential except where grazing is unmanaged. Topography provides escape habitat.Recreational uses
Recreational activities include hiking, horseback riding, camping, hunting, wildlife observation and photography. Landscape quality is good.
Wood products
Rubber tired equipment is best on these sandy soils for harvesting, site preparation, tree planting and precommercial thinning. Caution should be used on loose sands. Slopes are non-restrictive. Equipment could get stuck in sand with continuous heavy use.
Water erosion potential on cutover areas/bare ground/roads/trails/landings is slight to moderate. Wind erosion potential in this type of area is very high to high.
Compaction potential is poor. Soils are too coarse to rut. Revegetation potential is fair to good due to water holding capacity.
Harvest mature trees on a sustained yield basis. Final removal cuts and intermediate cuts are desirable. Thick stands need thinned to improve growth rate of trees left. Periodic ground fires will reduce dense understory vegetation competing for moisture. Loose sands ae the only possible limitation to mechanical tree removal. Control unwanted pests to limit tree damage and loss. Fire hazard could become extreme if understory fuel load builds up. Replanting suitability is fair to good, drought sandy soils could be a problem. Seedling mortality is moderate to severe. Natural regeneration is slightly limited bacause of competition for moisture. Seedlings need protection from grazing. Dense grass and forb cover may impede regeneration. Windthrow hazard is slight; rooting depth is greater than 30".
Table 10. Representative site productivity
Supporting information
Type locality
Location 1: San Juan County, NM Township/Range/Section T23N R20W S11 General legal description Toadlena Quad, Chuska Mountains, Navajo 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.
Contributors
Dan Carroll
Dean Schlichting
HSH
Karlynn Huling
Kenneth Gishi
Larry D. Ellicott
Steve BarkerApproval
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) Contact for lead author Date 04/30/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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