Natural Resources
Conservation Service

Ecological site F035XF614AZ

Loamy Upland
13-17" p.z. Gravelly
(PIED, JUOS)

Last updated: 5/20/2025
Accessed: 04/30/2026

Home / esd CATALOG / MLRA 035X / ecological site F035XF614AZ

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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.

MLRA notes

Major Land Resource Area (MLRA): 035X–Colorado Plateau

AZ CRA 35.6 - Colorado Plateau Pinyon-Juniper-Sagebrush

Elevations range from 5500 to 7000 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.

Table 1. Dominant plant species

Tree	(1) Pinus edulis (2) Juniperus osteosperma
Shrub	(1) Artemisia tridentata ssp. wyomingensis (2) Purshia stansburiana
Herbaceous	(1) Poa fendleriana (2) Pleuraphis jamesii

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Physiographic features

Site is located on footslopes, toeslopes, fan terraces of colluvial slopes at the base of cliffs and hills.

Table 2. Representative physiographic features

Landforms	(1) Cliff (2) Hill
Flooding frequency	None
Ponding frequency	None
Elevation	5600 – 6500 ft
Slope	2 – 20 %
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

Bar

Line

Figure 1. Monthly precipitation range

Bar

Line

Figure 2. Monthly average minimum and maximum temperature

Soil features

Soils are very deep. Surface textures are extremely gravelly fine sandy loam, very gravelly fine sandy loam, extremely gravelly loam, gravelly loam, loam and very gravelly loam. Subsurface textures are very gravelly loam, very cobbly loam, very gravelly sandy clay loam, extremely gravelly coarse sandy loam, loam, clay loam and gravelly clay.
Parent materials are alluvium, colluvium from limestone and sandstone. Geologic formation is Quaternary colluvium, alluvium from Kaibab limestone. Water erosion potential is slight to severe. Wind erosion potential is slight to moderate. Soils are non-saline, non-sodic with pH range of 6.1-8.4. Available water capacity is low to high.

Typical taxonomic units include:

SSA-623 Shivwits Area MU's 25 Goesling, 94 Katzine;
SSA-625 Mohave County NE part MU 57 Section;
SSA-629 Coconino County N. Kaibab part MU's 13, 14 & 17 Disterheff;
SSA-699 Hualapai/Havasupai area MU's 24 Mextank, Lykorly & Disterheff;
SSA-701 Grand Canyon area MU 171 Katzine;
SSA-717 Shiprock Area MU's 402 & 403 Chazner, 404 Tsezhin.

Table 4. Representative soil features

Parent material	(1) Alluvium – limestone and sandstone
Surface texture	(1) Very cobbly fine sandy loam (2) Extremely gravelly fine sandy loam (3) Extremely gravelly loam
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Slow to moderate
Soil depth	60 – 70 in
Surface fragment cover <=3"	10 – 55 %
Surface fragment cover >3"	5 – 40 %
Available water capacity (0-40in)	2.5 – 10 in
Calcium carbonate equivalent (0-40in)	3 – 35 %
Electrical conductivity (0-40in)	Not specified
Sodium adsorption ratio (0-40in)	Not specified
Soil reaction (1:1 water) (0-40in)	6.1 – 8.4
Subsurface fragment volume <=3" (Depth not specified)	15 – 55 %
Subsurface fragment volume >3" (Depth not specified)	0 – 35 %

Ecological dynamics

For state and transition model refer to Ecological Group ID DX035X02EESG20, Arizona Strip - Aridic Ustic - Limestone or Loamy Upland.

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.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Historic Climax Plant Community

State 1 submodel, plant communities

1.1. Historic Climax Plant Community

State 1
Historic Climax Plant Community

Community 1.1
Historic Climax Plant Community

The potential plant community consists of appx. 60% tree canopy cover over an understory of grasses, forbs, shrubs and small trees. In the herbaceous/shrub stage, shrubs and grasses dominate with some tree seedlings and forbs present. In the immature stage, medium sized trees are competing with shrubs. Grasses and some forbs are present. In the mature/climax stage, trees are dominant. Shrubs will dominate the understory; grasses and forbs are few.

Figure 3. 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 4. 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

Figure 5. Plant community growth curve (percent production by month). AZ3603 , 35.6 13-17" p.z. Wyoming big sagebrush. Most growth occurs in 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	5	15	20	20	20	10	10	0	0

Figure 6. 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

Additional community tables

Table 5. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 6. Community 1.1 forest overstory composition

Common name	Symbol	Scientific name	Nativity	Height ft	Canopy cover (%)	Diameter in	Basal area (square ft/acre)
Tree
twoneedle pinyon	PIED	Pinus edulis	Native	5-30	20-40	4-15	0
Utah juniper	JUOS	Juniperus osteosperma	Native	1-16	20-40	3-12	0

Table 7. Community 1.1 forest understory composition

Common name	Symbol	Scientific name	Nativity	Height (ft)	Canopy cover (%)
Grass/grass-like (Graminoids)
James' galleta	PLJA	Pleuraphis jamesii	Native	0.1–1	3–7
muttongrass	POFE	Poa fendleriana	Native	0.1–1	1–3
Forb/Herb
Wright's bird's beak	COWR2	Cordylanthus wrightii	Native	0.5–2.5	1–2
Siler's penstemon	PELIS	Penstemon linarioides ssp. sileri	Native	0.2–1.5	1–2
phlox	PHLOX	Phlox	Native	0.2–1	1–2
Shrub/Subshrub
Sonoran scrub oak	QUTU2	Quercus turbinella	Native	1–6	5–10
mountain big sagebrush	ARTRV	Artemisia tridentata ssp. vaseyana	Native	1–2.5	5–10
Stansbury cliffrose	PUST	Purshia stansburiana	Native	1–6	2–8
broom snakeweed	GUSA2	Gutierrezia sarothrae	Native	0.2–1	2–5
Utah serviceberry	AMUT	Amelanchier utahensis	Native	1–4	1–5
fourwing saltbush	ATCA2	Atriplex canescens	Native	0.5–2.5	2–5
tulip pricklypear	OPPH	Opuntia phaeacantha	Native	0.2–2	1–4
banana yucca	YUBA	Yucca baccata	Native	0.1–2.5	1–2
Tree
Utah juniper	JUOS	Juniperus osteosperma	Native	1–15	20–40
twoneedle pinyon	PIED	Pinus edulis	Native	4–25	20–40
Wyoming big sagebrush	ARTRW8	Artemisia tridentata ssp. wyomingensis	Native	2–8	10–15

Interpretations

Animal community

Due to the thickness of trees, the site is only fairly suitable for grazing by cattle, sheep and horses in summer and fall. Management considerations are grazing systems, proper grazing use and snow covered forage.

Water can be found in some springs and man-made water facilities. Elk and Deer use the site for winter cover. Food is adequate for native wildlife species. Topography provides escape habitat.

Recreational uses

Recreational activities include hiking, hunting, wildlife observations and photography. Aesthetic appeal is fair.

Wood products

Rubber-tired equipment is best used for harvesting & site preparation. All kinds of equipment is suitable to tree planting and precommercial thinning. Slopes of 15% may limit some equipment. Erosion potential is very slight. Rock litter protects the soils. Water erosion may occur on slopes over 10% however. Compaction potential is good. Rutting will occur when soils are wet. Revegetation potential is good.

Harvest mature trees when canopy exceeds 40%. Cut posts and Christmas trees to improve wood growth of the remaining trees. Prescribed burning is not recommended. Mechanical tree removal is practical, although gravel in soils may cause some difficulty. Control pests to prevent tree damage and loss. Fire hazard is medium due to dense shrub understory's potential to be a high fuel load. Replating potential is good, however gravel in soils may cause problems. Seedling mortality is moderate to severe. Natural regeneration is slow, but will occur in time. Seedlings should be protected from grazing. Plant competition is moderate as shrubs compete for moisture. Windthrow hazard is slight. Trees root well in the deep soils.

Table 8. 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
twoneedle pinyon	PIED	85	95	10	13	–	–	–

Supporting information

Type locality

Location 1: Coconino County, AZ
Township/Range/Section	T30N R8W S34
General legal description	Hockey Puck Spring Quad, 0.5 mile east of Mexican Tank; Sec 34, T30N, R8W; Hualapai Indian Reservation, AZ.

Contributors

HSH
Karlynn Huling
Larry D. Ellicott

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)
Contact for lead author
Date	04/30/2026
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:

Download reference sheet

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