Natural Resources
Conservation Service
Ecological site R035XY305UT
Upland Loam (Gambel Oak)
Last updated: 5/19/2025
Accessed: 05/05/2026
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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
MLRA notes
Major Land Resource Area (MLRA): 035X–Colorado Plateau
This ecological site occurs in the northern portion of MLRA 35, Colorado Plateau Province. It is found principally in the Canyon Lands and High Plateaus of Utah sections within that MLRA. This area has been structurally uplifted over time while rivers flowing across it were cutting down into its bedrock. Areas of shale, sandstone, limestone, dolomite, and volcanic rock outcrop are found throughout the region.
Ecological site concept
This ecological site occurs within the upland zone of MLRA 035X (Colorado Plateau) in southwest Utah. It is found on plateaus, valleys, valley floors and structural benches at elevations between 5,270 and 7,850 feet and occurs on slopes ranging from 2 to 35 percent. The average annual precipitation ranges from 13 to 17 inches. The soils of this ecological site are deep or very deep and well drained or somewhat excessively drained. These soils are usually formed in alluvium, slope alluvium or eolian deposits derived from sandstone and shale. The soil textures range from loamy sand to silty clay loam; but are usually sandy loam, loam or sandy clay loam. The soil temperature regime is mesic and the soil moisture regime is aridic ustic. The dominant plant aspect consists of Gambel oak shrub communities with intermixed mountain big sagebrush and an understory component of grasses and forbs. It is not uncommon for the site to burn and the site is typically heavily dominated by Gambel oak following post-fire succession. The site is less susceptible to the establishment of cheatgrass and other non-native species following a burn.
Table 1. Dominant plant species
Tree (1) Quercus gambelii
(2) Juniperus osteospermaShrub (1) Artemisia tridentata ssp. vaseyana
(2) Purshia tridentataHerbaceous Not specified
Physiographic features
This ecological site occurs on plateaus, valleys, valley floors and structural benches. Slopes typically range from 2 to 35 percent. Elevation ranges are generally 5,270 to 7,850 feet.
Table 2. Representative physiographic features
Landforms (1) Plateau
(2) Valley
(3) Structural bench
Runoff class Low to medium Flooding frequency None Ponding frequency None Elevation 5270 – 7850 ft Slope 2 – 35 % Climatic features
The climate is characterized by warm summers and cool to cold winters. Approximately 35 to 40 percent of the annual moisture comes during the plant growth period from April 1 through September 30. During the growing season, July, August and September are the months that provide the greatest amount of moisture. On the average, May and June are the months that provide the least amount of annual moisture and January and February are the months that provide the greatest amount of annual moisture.
Table 3 Representative climatic features
Frost-free period (characteristic range) 110-120 days Freeze-free period (characteristic range) 150-150 days Precipitation total (characteristic range) 20 in Frost-free period (actual range) 110-120 days Freeze-free period (actual range) 150-150 days Precipitation total (actual range) 20-20 in Frost-free period (average) 120 days Freeze-free period (average) 150 days Precipitation total (average) 20 in Characteristic rangeActual rangeBarLineFigure 1. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 2. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 3. Monthly maximum temperature range
BarLineFigure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6 Annual average temperature pattern
Climate stations used
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(1) ORDERVILLE [USC00426534], Orderville, UT
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(2) NEW HARMONY [USC00426181], Hurricane, UT
">Influencing water features
Due to the landscape position, this site is not influenced by streams or wetlands.
Soil features
The soils of this ecological site are deep or very deep and well drained or somewhat excessively drained. These soils are usually formed in alluvium, slope alluvium or eolian deposits derived from sandstone and shale; lower horizons may contain residuum from shale or sandstone. The soils are moderately coarse textured to moderately fine textured; mainly fine sandy loam, loam or sandy clay loam. Loamy sand and silty clay loam textured soils also occur, but are less common. Permeability on these soils ranges from moderately rapid to moderately slow. The available water holding capacity ranges from 2.5 to 8.7 inches in the upper 40 inches of the soil and averages about 6 inches in most soils. The soils are generally non-saline and neutral to moderately alkaline. The soil temperature regime is mesic and the soil moisture regime is aridic ustic.
This site has been used in the following soil surveys and has been correlated to the following
components:
Soil Survey Soil Component
UT642 – Kane County Area Caval,
Flugle, Orderville, Parkelei, Parkelei Family, Ramps
UT690 – Zion National Park Caval
Typical Profile:
A 0-7 inches Fine Sandy Loam Neutral
Bt1 7-17 inches Fine Sandy Loam Slightly Alkaline
Bt2 17-42 inches Sandy Clay Loam Slightly Alkaline
Btk 42-54 inches Loam Slightly Alkaline
Bk 54-60 inches Loam Moderately AlkalineTable 4. Representative soil features
Parent material (1) Eolian deposits – sandstone
(2) Alluvium – sandstone and shale
(3) Slope alluvium – basalt
Surface texture (1) Fine sandy loam
(2) Loam
(3) Sand
Family particle size (1) Loamy
Drainage class Well drained to excessively drained Permeability class Moderately slow to moderately rapid Soil depth 40 – 60 in Surface fragment cover <=3" 0 – 10 % Surface fragment cover >3" 0 – 3 % Available water capacity
(0-40in)2.5 – 8.7 in Calcium carbonate equivalent
(0-40in)0 – 1 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Soil reaction (1:1 water)
(0-40in)6 – 6.6 Ecological dynamics
The Upland Loam (QUGA) R035XY305UT is an ecological site which occurs within the upland zone of MLRA 035X (Colorado Plateau) in southwest Utah. The dominant aspect of the plant community is a shrub component with Gambel oak being the primary or dominant species. Mountain big sagebrush may also be common, with other shrubs occurring in smaller amounts. An herbaceous understory component comprised of grasses and forbs occurs on the site including species such as, but not limited to, Sandberg bluegrass, muttongrass, slender wheatgrass, sand dropseed, needle and thread, other perennial grasses, hairy false goldenaster, milkvetch, penstemon, varileaf phacelia and other perennial and annual forbs. Trees are uncommon although scattered singleleaf pinyon and Utah juniper may occur in small amounts.
Plant species which are most likely to invade the site if plant cover deteriorates include species such as, but not limited to, cheatgrass, annual forbs, dandelion, houndstongue, rubber rabbitbrush, broom snakeweed, Utah juniper and pinyon pine. The site is not well suited to grazing due to the dominate shrub component and limited herbaceous understory, but browsing by livestock and wildlife does occur. A majority of the burns which occur on the site typically consume large areas and exhibit intense behavior due to the high density shrub communities and associated heavy fuel loading. When the plant community is burned, post-fire regeneration is almost completely dominated by Gambel oak, which typically occurs in the scrub growth form following post-fire regeneration. Suitability for rangeland seeding is limited due to the heavy dominance of Gambel oak which outcompetes herbaceous grasses and forbs.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 textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Reference StateThe reference state represents the plant communities and ecological dynamics of the upland loam (Gambel oak) site. This state includes the biotic communities that become established on the ecological site if all successional sequences are completed under the natural disturbance regime. The reference state is generally dominated by perennial grasses and Gambel oak. The reference state is self sustaining and resistant to change due to high resistance to natural disturbances and high resilience following natural disturbances. When natural disturbances occur, the rate of recovery is variable due to disturbance intensity. Once invasive plants establish, return to the reference state may not be possible.
Community 1.1
Gambel oak/ slender wheatgrassThis community is characterized by an overstory of Gambel oak. Mountain big sagebrush may also be common, with other shrubs occurring in smaller amounts. An herbaceous understory component comprised of grasses and forbs occurs on the site including species such as, but not limited to, Sandberg bluegrass, muttongrass, slender wheatgrass, sand dropseed, needle and thread, other perennial grasses, hairy false goldenaster, milkvetch, penstemon, varileaf phacelia and other perennial and annual forbs. Trees are uncommon although scattered singleleaf pinyon and Utah juniper may occur in small amounts.
Dominant plant species
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Gambel oak (Quercus gambelii), shrub
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mountain big sagebrush (Artemisia tridentata ssp. vaseyana), shrub
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bluegrass (Poa), grass
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slender wheatgrass (Elymus trachycaulus), grass
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hairy false goldenaster (Heterotheca villosa), other herbaceous
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)Grass/Grasslike – – – Forb – – – Shrub/Vine – – – Total – – – Community 1.2
Post-fire community/Gambel oak thicketWhen the plant community is burned, post-fire regeneration is almost completely dominated by Gambel oak, which typically occurs in the scrub growth form following post-fire regeneration.
Community 1.3
Encroachment by tree species/decreased Gambel oak densityThis community results from time without disturbance, typically fire, which allows Utah juniper and pinyon pine to become established on the site.
Pathway 1.1a
Community 1.1 to 1.2Community 1.1 to 1.2 This pathway occurs when the plant community is burned eliminating mature Gambel oak. Gambel oak resprouts readily after fire establishing the thicket community.
Pathway 1.1b
Community 1.1 to 1.3Community 1.1 to 1.3 Time without disturbance results in encroachment by Utah juniper and two-needle pinyon.
Pathway 1.2a
Community 1.2 to 1.1Community 1.2 to 1.1 Time without disturbance results in establishment of the herbaceous understory.
Pathway 1.3a
Community 1.3 to 1.2Community 1.3 to 1.2 Fire eliminates mature Gambel oak, Utah juniper, and two-needle pinyon.
State 2
Current Potential StateThe Current Potential State is similar to the Reference State in community structure and ecological function, however the presence of invasive species reduces the resillience of the site to further degradation.
Community 2.1
Gambel oak/slender wheatgrass/non-native speciesThis community is characterized by an oversstory of Gambel oak. Mountain big sagebrush may also be present. The herbaceous layer has both native and non-native species. Herbacous species most likely to invade this site include, but are not limited to, cheatgrass, annual forbs, and dandelion. Broom snakeweed and rubber rabbitbrush are native shrubs which may also increase as plant cover deteriorates.
Dominant plant species
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Gambel oak (Quercus gambelii), shrub
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mountain big sagebrush (Artemisia tridentata ssp. vaseyana), shrub
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cheatgrass (Bromus tectorum), grass
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hairy false goldenaster (Heterotheca villosa), other herbaceous
Figure 8. Annual production by plant type (representative values) or group (midpoint values)
Community 2.2
Gambel oak thicket/non-native speciesThe post fire community is usually dominated by Gambel oak but can include opportunistic species such as cheatgrass and non-native annual forbs
Community 2.3
Decreased Gambel oak density/ encroachment by Utah juniper and pinyon/non-native speciesThis community is characterized by mature Gambel oak. Utah juniper and two-needle pinyon are increasing in the community and non-native grasses are increasing.
Community 2.4
Seeded Gambel oak woodland/smooth brome/ native and non-native species in the understoryThis community results from rangeland seeding. Species composition is variable, depending on the seed mix used, but is typically dominated by introduced perennial grasses.
Pathway 2.1a
Community 2.1 to 2.2Community 2.1 to 2.2 This pathway occurs when the plant community is burned eliminating mature Gambel oak. Gambel oak resprouts readily after fire establishing the thicket community.
Pathway 2.1b
Community 2.1 to 2.3Community 2.1 to 2.3 Time without disturbance results in encroachment by Utah juniper and two-needle pinyon. Non-native species may also increase.
Pathway 2.1c
Community 2.1 to 2.4Community 2.1 to 2.4 A rangeland seeding, typically preceded by brush management and typically with introduced perennial grasses.
Pathway 2.2a
Community 2.2 to 2.1Community 2.2 to 2.1 Time without disturbance results in establishment of the herbaceous understory.
Pathway 2.2b
Community 2.2 to 2.4Community 2.2 to 2.4 A rangeland seeding, typically preceded by brush management and typically with introduced perennial grasses.
Pathway 2.3a
Community 2.3 to 2.2Community 2.3 to 2.2 Fire eliminates mature Gambel oak, Utah juniper, and two-needle pinyon.
Pathway 2.3b
Community 2.3 to 2.4Community 2.3 to 2.4 A rangeland seeding, typically preceded by brush management and typically with introduced perennial grasses.
Transition T1A
State 1 to 2This transition results from the introduction and establishment of non-native species
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant Grasses – bluegrass POA Poa 0–20 – muttongrass POFE Poa fendleriana 0–10 – needle and thread HECO26 Hesperostipa comata 0–10 – Sandberg bluegrass POSE Poa secunda 0–10 – 2 Sub-dominant Grasses – slender wheatgrass ELTR7 Elymus trachycaulus 0–5 – sand dropseed SPCR Sporobolus cryptandrus 0–5 – Indian ricegrass ACHY Achnatherum hymenoides 0–5 – western wheatgrass PASM Pascopyrum smithii 0–5 – Forb3 Dominant Forbs – hairy false goldenaster HEVI4 Heterotheca villosa 20–40 – 4 Sub-dominant Forbs – milkvetch ASTRA Astragalus 0–10 – Utah penstemon PEUT Penstemon utahensis 0–10 – varileaf phacelia PHHE2 Phacelia heterophylla 0–10 – longleaf phlox PHLO2 Phlox longifolia 0–10 – aster ASTER Aster 0–10 – beardtongue PENST Penstemon 0–10 – scarlet gilia IPAG Ipomopsis aggregata 0–5 – goldenrod SOLID Solidago 0–5 – Shrub/Vine5 Dominant Shrubs – Gambel oak QUGA Quercus gambelii 500–700 – mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 75–125 – 6 Sub-dominant Shrubs – skunkbush sumac RHTR Rhus trilobata 0–10 – greenleaf manzanita ARPA6 Arctostaphylos patula 0–10 – yucca YUCCA Yucca 0–10 – plains pricklypear OPPO Opuntia polyacantha 0–10 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–10 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–10 – Tree7 Trees – twoneedle pinyon PIED Pinus edulis – – singleleaf pinyon PIMO Pinus monophylla – – Utah juniper JUOS Juniperus osteosperma – – fir ABIES Abies – – 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 (%) Grass/Grasslike1 Dominant Grasses – cheatgrass BRTE Bromus tectorum 45–65 – blue grama BOGR2 Bouteloua gracilis 0–15 – sand dropseed SPCR Sporobolus cryptandrus 0–15 – needle and thread HECO26 Hesperostipa comata 0–15 – 2 Sub-dominant Grasses – smooth brome BRIN2 Bromus inermis 0–5 – Indian ricegrass ACHY Achnatherum hymenoides 0–5 – squirreltail ELEL5 Elymus elymoides 0–5 – western wheatgrass PASM Pascopyrum smithii 0–5 – Forb3 Dominant Forbs – hairy false goldenaster HEVI4 Heterotheca villosa 25–75 – lupine LUPIN Lupinus 1–20 – gooseberryleaf globemallow SPGR2 Sphaeralcea grossulariifolia 0–15 – buckwheat ERIOG Eriogonum 0–15 – Utah penstemon PEUT Penstemon utahensis 0–15 – 4 Sub-dominant Forbs – goldenrod SOLID Solidago 0–5 – Indian paintbrush CASTI2 Castilleja 0–5 – pale evening primrose OEPA Oenothera pallida 0–5 – mustard BRASS2 Brassica 0–5 – dandelion TARAX Taraxacum 0–5 – common mullein VETH Verbascum thapsus 0–5 – Shrub/Vine5 Dominant Shrubs – Gambel oak QUGA Quercus gambelii 325–525 – mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 50–100 – 6 Sub-dominant Shrubs – chokecherry PRVI Prunus virginiana 10–30 – antelope bitterbrush PUTR2 Purshia tridentata 5–25 – plains pricklypear OPPO Opuntia polyacantha 0–5 – greenleaf manzanita ARPA6 Arctostaphylos patula 0–5 – Utah serviceberry AMUT Amelanchier utahensis 0–5 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–5 – skunkbush sumac RHTR Rhus trilobata 0–5 – spineless horsebrush TECA2 Tetradymia canescens 0–5 – Tree7 Trees – Rocky Mountain juniper JUSC2 Juniperus scopulorum – – Table 10. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 2.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 12. Community 2.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Inventory data references
Vegetative Data References Community 1.1 • 2016UT0531_086 (085) • 2016UT0531_147 (364) • T40S R11W S05 (2) • T40S R11W S09 (271-272) • T40S R11W S15 (276-277) Transition of Upland Loam (QUGA) R035XY305UT and Upland Sand (ARTRV) R035XY307UT Vegetative Data References Community 2.1 • 2014UT0531_051-057 • 2014UT0531_059 (058 060) • 2017UT0531_301
Contributors
T. Simper
Approval
Kendra Moseley, 5/19/2025
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 05/05/2026 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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