Natural Resources
Conservation Service
Ecological site F035XF619AZ
Limestone Upland
13-17" p.z.
(JUOS, PIED)
Last updated: 5/20/2025
Accessed: 04/28/2026
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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 35.6 - the Colorado Plateau Pinyon-Juniper-Sagebrush
The Common Resource Area occurs within the Colorado Plateau Physiographic Province. Elevations range from 5800 to 7300 feet and precipitation averages 13 to 17 inches per year. Vegetation includes pinyon, juniper, big sagebrush, cliffrose, Mormon tea, muttongrass, prairie junegrass, squirreltail, western wheatgrass, and blue grama. The soil temperature regime is mesic and the soil moisture regime is aridic 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 on this site are very shallow to moderately deep with surface textures that include extremely cherty very fine sandy loam, extremely cobbly loam and gravelly to extremely gravelly loam. This ecological site is found on hills, escarpments and fan terraces of undulating plateaus. Slopes generally range from 2-25%.
Table 1. Dominant plant species
Tree (1) Juniperus osteosperma
(2) Pinus edulisShrub (1) Purshia stansburiana
(2) Quercus turbinellaHerbaceous (1) Bouteloua curtipendula
(2) Poa fendlerianaPhysiographic features
This site is found on hills, escarpments and fan terraces of undulating plateaus very shallow to moderately deep soils. Slopes generally range from 2-25% with some areas of short runs up to 35%.
Table 2. Representative physiographic features
Landforms (1) Hill
(2) Escarpment
(3) Terrace
Flooding frequency None Ponding frequency None to rare Elevation 5800 – 7300 ft Slope 2 – 25 % Aspect Aspect is not a significant factor Climatic features
The climate of this land resource unit is semiarid with warm summers and cool winters. The mean annual precipitation ranges from 13 – 17 inches, but it is very erratic, often varying substantially from year to year. The majority of the precipitation comes from October through April. This precipitation comes as gentle rain or snow from frontal storms coming out of the Pacific Ocean. Snow is common from November through February. Generally no more than a few inches of snow accumulates, melting within a few days, but may last a week or more. The remaining precipitation comes from July through September as spotty, unreliable and sometimes violent thunderstorms. The moisture for this precipitation originates in the Gulf of Mexico (and the Pacific Ocean in the fall) and flows into the area on the north end of the Mexican monsoon. Late May through late June is generally a dry period. The mean annual air temperature ranges from 47 to 49 degrees Fahrenheit (F). The frost-free period (air temperature > 32 degrees F) ranges from 113 to 144 days (@ 50 percent probability). Strong winds are common, especially in the spring.
Table 3 Representative climatic features
Frost-free period (average) 140 days Freeze-free period (average) 160 days Precipitation total (average) 20 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 on this site are very shallow to moderately deep with surface textures that include extremely cherty very fine sandy loam, extremely cobbly loam and gravelly to extremely gravelly loam. Subsurface textures include loam, very gravelly, very cobbly to extremely cobbly loams, gravelly clay loam, clay, cobbly clay to very cobbly clay. They are derived from residuum and alluvium from limestone and basalt. The Geologic formations include Tonto Group (Muav limestone); Quaternary alluvium from Kaibab limestone; basalt.
Typical taxonomic units include:
SSA-625 Mohave county NE part MU's 71 & 72 Yumtheska;
SSA-629 Coconino County N. Kaibab part MU's 14 17 & 52 Houserock, 51 52 Yumtheska;
SSA-697 Central Mohave county MU's 33 Tovar, 33 Dye, 88 Milkweed, 88 Quartermaster;
SSA-699 Hualapai/Havasupai Area MU's 47 Toqui & Tovar, 57 Wodomont, 25 Milkweed & Quartermaster;
SSA-701 Grand Canyon area MU's 23 Chunkmonk family, 23 123 167 Wodomont family, 36 Disterheff, 83 84 Natank, 167 Topocoba family & 36 83 84 125 131 172 173 175 Yumtheska;
SSA-707 Little Colorado MU - 9 Gladel.Table 4. Representative soil features
Parent material (1) Residuum – basalt
(2) Alluvium – limestone
Surface texture (1) Very gravelly loam
(2) Extremely cobbly loam
(3) Extremely gravelly loam
Family particle size (1) Loamy
Drainage class Moderately well drained to well drained Permeability class Slow to moderately rapid Soil depth 5 – 30 in Surface fragment cover <=3" 15 – 30 % Surface fragment cover >3" 20 – 45 % Available water capacity
(0-40in)0 – 2.5 in Calcium carbonate equivalent
(0-40in)15 – 40 % Soil reaction (1:1 water)
(0-40in)6.6 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 15 % Subsurface fragment volume >3"
(Depth not specified)10 – 35 % 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. Limestone Upland 13-17"p.z.
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 StateThis is a forest site with an overstory comprised of juniper and pinyon with approximately 45% to 50% canopy cover. The understory is comprised of shrubs, grasses and minor amounts of forbs and small trees.
Community 1.1
Juniper-Pinyon / Shrubs and Grasses (HCPC)
Figure 5. Limestone Upland 13-17" p.z. Phase 1.1
Figure 6. Limestone Upland 13-17" p.z. Phase 1.2
This site has an overstory comprised of pinyon pine (30%) and juniper (70%). The tree canopy cover is generally 40-55%, but can be higher. The understory is comprised of aproximately 60% shrubs, 30% grasses and 5% each small trees and forbs. Understory species include sideoats grama, muttongrass, blue grama, penstemon, Stansbury cliffrose, turbinella oak and desert ceanothus.
Non-native plant species may be present in minor amounts. Once non-native plants are introduced into the plant community, it is very difficult to eliminate these plants from the site.
Forest understory. The understory responds to the density of the overstory canopy. The relationship of sparse, Representative Value and dense canopy cover versus the understory composition and production is shown in the third table below.
Figure 7. 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 210 270 330 Grass/Grasslike 105 135 165 Tree 15 25 35 Forb 10 20 30 Total 340 450 560 Figure 8. Plant community growth curve (percent production by month). AZ3929 , 35.6 13-17" p.z. turbinella oak. Growth begins in spring and continues through the summer. Seed set occurs in 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 10 15 20 15 15 15 10 0 0 Figure 9. Plant community growth curve (percent production by month). AZ3930 , 35.6 13-17" p.z. banana yucca. Most leaf growth occurs in late spring. Flowers in summer. Seed set occurs in late summer to 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 10 10 20 20 20 10 10 0 0 Figure 10. Plant community growth curve (percent production by month). AZ3506 , 35.6 13-17" p.z. blue grama. Growth occurs mostly in summer and early fall during the 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 5 10 15 25 30 15 0 0 0 Figure 11. Plant community growth curve (percent production by month). AZ3512 , 35.6 13-17" p.z. Stansbury cliffrose. Growth begins in spring and continues through the summer. Stem elongation, flowering, and seed set occur in 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 0 0 5 20 20 30 20 5 0 0 0 Figure 12. Plant community growth curve (percent production by month). AZ3515 , 35.6 13-17" p.z. sideoats grama. Most growth occurs in summer and early fall during the 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 5 10 20 30 20 10 5 0 0 Figure 13. Plant community growth curve (percent production by month). AZ3602 , 35.6 13-17" p.z. muttongrass. Most growth occurs in early to mid spring, plants may be green in the fall. Seed set occurs by 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 0 10 20 30 15 5 5 10 5 0 0 Community 1.2
Juniper-Pinyon / Increased ShrubsIn this community the understory is affected by disturbace that reduces the grass component and shrubs increase and become more dominant. Shrub species that can increase are broom snakeweed, mormon tea, big sage and banana yucca.
Non-native plant species may be present in minor amounts. Once non-native plants are introduced into the plant community, it is very difficult to eliminate these plants from the site.Pathway 1.1a
Community 1.1 to 1.2Disturbance that reduces perennial grasses, unmanaged grazing, drought, fire suppression.
Pathway 1.2A
Community 1.2 to 1.1Brush removal and possibly tree removal in conjunction with grazing 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 Grasses 65–115 muttongrass POFE Poa fendleriana 45–70 – sideoats grama BOCU Bouteloua curtipendula 45–65 – blue grama BOGR2 Bouteloua gracilis 23–45 – 2 Occasional Grasses 20–70 Indian ricegrass ACHY Achnatherum hymenoides 5–23 – Fendler's threeawn ARPUF Aristida purpurea var. fendleriana 0–23 – black grama BOER4 Bouteloua eriopoda 5–23 – squirreltail ELEL5 Elymus elymoides 5–23 – needle and thread HECO26 Hesperostipa comata 5–23 – prairie Junegrass KOMA Koeleria macrantha 0–23 – Grass, annual 2GA Grass, annual 0–9 – Grass, perennial 2GP Grass, perennial 0–9 – Forb3 Forbs 15–30 Forb, annual 2FA Forb, annual 0–10 – Forb, perennial 2FP Forb, perennial 0–10 – pingue rubberweed HYRI Hymenoxys richardsonii 0–9 – paperflower PSILO3 Psilostrophe 0–9 – globemallow SPHAE Sphaeralcea 0–5 – Shrub/Vine4 Common Shrubs 135–225 Stansbury cliffrose PUST Purshia stansburiana 45–90 – Sonoran scrub oak QUTU2 Quercus turbinella 23–68 – desert ceanothus CEGR Ceanothus greggii 23–68 – pricklypear OPUNT Opuntia 23–45 – 5 Other Shrubs 65–120 banana yucca YUBA Yucca baccata 5–45 – broom snakeweed GUSA2 Gutierrezia sarothrae 5–45 – Fremont's mahonia MAFR3 Mahonia fremontii 0–23 – Shrub (>.5m) 2SHRUB Shrub (>.5m) 0–23 – Subshrub (<.5m) 2SUBS Subshrub (<.5m) 0–23 – pointleaf manzanita ARPU5 Arctostaphylos pungens 0–23 – Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 5–23 – mormon tea EPVI Ephedra viridis 5–23 – ashy silktassel GAFL2 Garrya flavescens 0–23 – Tree6 Trees 15–35 Utah juniper JUOS Juniperus osteosperma 5–25 – twoneedle pinyon PIED Pinus edulis 0–15 – singleleaf pinyon PIMO Pinus monophylla 0–15 – Table 7. Community 1.1 forest overstory composition
Common name Symbol Scientific name Nativity Height ft Canopy cover (%) Diameter in Basal area (square ft/acre) TreeUtah juniper JUOS Juniperus osteosperma Native 2-18 30-40 4-13 0 singleleaf pinyon PIMO Pinus monophylla Native 3-25 10-20 3-11 0 Table 8. Community 1.1 forest understory composition
Common name Symbol Scientific name Nativity Height (ft) Canopy cover (%) Grass/grass-like (Graminoids)sideoats grama BOCU Bouteloua curtipendula Native 0.3–2.7 5–15 blue grama BOGR2 Bouteloua gracilis Native 0.1–1.2 3–8 Indian ricegrass ACHY Achnatherum hymenoides Native 0.2–1.5 1–4 black grama BOER4 Bouteloua eriopoda Native 0.1–1.5 1–3 squirreltail ELELE Elymus elymoides ssp. elymoides Native 0.3–3.2 1–3 needle and thread HECOC8 Hesperostipa comata ssp. comata Native 0.2–4 1–3 Fendler's threeawn ARPUF Aristida purpurea var. fendleriana Native 0.1–1.2 1–2 muttongrass POFE Poa fendleriana Native 0.1–1.5 1–2 Shrub/SubshrubStansbury cliffrose PUST Purshia stansburiana Native 3–8 8–15 Sonoran scrub oak QUTU2 Quercus turbinella Native 2–7 4–10 desert ceanothus CEGR Ceanothus greggii Native 1–5 3–9 mormon tea EPVI Ephedra viridis Native 1–3 2–5 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana Native 0.3–3.5 2–5 pointleaf manzanita ARPU5 Arctostaphylos pungens Native 0.3–4 3–5 broom snakeweed GUSA2 Gutierrezia sarothrae Native 0.1–1.1 2–5 ashy silktassel GAFL2 Garrya flavescens Native 1–5 1–4 Fremont's mahonia MAFR3 Mahonia fremontii Native 1–5 1–3 Fremont's mahonia MAFR3 Mahonia fremontii Native 1–6 1–2 TreeUtah juniper JUOS Juniperus osteosperma Native 2–20 30–40 singleleaf pinyon PIMO Pinus monophylla Native 2–11 10–20 Table 9. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
The suitability of this site for livestock grazing is only fair. Many of the brush species are not palatable. Management considerations include Prescribed Grazing, Water developments, stock trails on the steep slopes and Range Planting after disturbance such as fire, wood harvesting etc.. Wildlife use may be limited because of scarce water sources in natural springs and pockets. There is, however, a good diversity of food sources, good cover for most species and the topography provides escape habitat.
Recreational uses
Recreational activities available are hiking, wildlife observations, photography and star gazing at night.
Wood products
Steep slopes, rock outcrops and shallow soils limit the types of equipment and the ability to do tree planting and harvesting. Revegetation potential is poor due to shallow rocky soil and steep slopes. Rubber tired equipment on less than 15% slopes and crawler tractors on steeper slopes.
Silvicultural considerations and potentials include: harvesting mature trees (fuelwood and posts) when canopy exceeds 35%; harvesting of posts and Christmas trees will thin and improve the stand; prescribed burning is not recommended due to the effect of increasing the shrub density and retarding the tree growth.
Suitability for replanting is poor due to shallow rocky soils.
Seedling mortality is severe for same reason.
Natural regeneration is slow, but can occur in time.
Seedlings should be protected from trampling, etc. due to grazing.
Plant competition is moderate because of shallow soil.
Windthrow hazard is moderate as some trees may blow over due to shallow soil.
Table 10. Representative site productivity
Common name Symbol Site index low Site index high CMAI low CMAI high Age of CMAI Site index curve code Site index curve basis Citation Utah juniper JUOS 60 70 6 7 – – – Supporting information
Type locality
Location 1: Mohave County, AZ Township/Range/Section T25N R17W S11 General legal description Milkweed Canyon SW Quad - 1 mile SE of Quail Tank; Section 11, T25N, R17W; Hualapai Indian Reservation, AZ. 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
Karlynn Huling
Larry D. EllicottApproval
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 04/28/2026 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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