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Ecological site R028AB320UT
Upland Shallow Hardpan (Singleleaf pinyon-Utah juniper) South
Last updated: 6/12/2025
Accessed: 06/28/2026
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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.
MLRA notes
Major Land Resource Area (MLRA): 028A–Ancient Lake Bonneville
MLRA 28A occurs in Utah (82 percent), Nevada (16 percent), and Idaho (2 percent). It encompasses approximately 36,775 square miles (95,246 square kilometers). A large area west and southwest of Great Salt Lake is a salty playa. This area is the farthest eastern extent of the Great Basin Section of the Basin and Range Province of the Intermontane Plateaus. It is an area of nearly level basins between widely separated mountain ranges trending north to south. The basins are bordered by long, gently sloping alluvial fans. The mountains are uplifted fault blocks with steep side slopes. Most of the valleys are closed basins containing sinks or playa lakes. Elevation ranges from 3,950 to 6,560 feet (1,204 to 2000 meters) in the basins and from 6,560 to 11,150 feet (1996 to 3398 meters) in the mountains. Much of the MLRA has alluvial valley fill and playa lakebed deposits at the surface from pluvial Lake Bonneville, which dominated this MLRA 13,000 years ago. A level line of remnant lake terraces on some mountain slopes indicates the former extent of this glacial lake. The Great Salt Lake is what remains of the pluvial lake.
Mountains in the interior of this MLRA consist of tilted blocks of marine sediments from Cambrian to Mississippian age with scattered outcrops of Tertiary continental sediments and volcanic rocks. The average annual precipitation is 5 to 12 inches (13 to 30 cm) in the valleys and ranges up to 49 inches (124 cm) in the mountains. Most of the rainfall in the southern LRU occurs as high-intensity, convective thunderstorms during the growing season (April through September). The driest period is from midsummer to early autumn in the northern LRU. Precipitation in winter typically occurs as snow. The average annual temperature is 39 to 53 °F (4 to 12 °C). The freeze-free period averages 165 days and ranges from 110 to 215 days, decreasing in length with increasing elevation. The dominant soil orders in this MLRA are Aridisols, Entisols, and Mollisols. Soils are dominantly in the mesic or frigid soil temperature regime, aridic or xeric soil moisture regime, and mixed mineralogy. The soils are generally well drained, loamy or loamy-skeletal, and very deep.LRU notes
The Basin and Range South LRU has mountain ranges that are about 40 percent sedimentary/metasedimentary (limestone/quartzite dominant) and about 40 percent Tertiary volcanics. The basin floors are generally higher in the southern LRU than in the north LRU between 4,900 and 6,100 feet (1,493 to 1,859 meters) in elevation. The Basin and Range South LRU also exhibits patterns of summers with a greater relative amount of precipitation in July and August coming from convective storms (ustic trending pattern). Pinyon and juniper ecological sites have a great percentage of pinyon pine (Pinus edulis or monophylla) than Utah juniper (Juniperus osteosperma), with pinyon pine up to 50 percent of the tree composition in the semidesert zones and more than 50 percent in upland zones. Warm season grasses, such as James’ galleta (Pleuraphis jamesii) or blue grama (Bouteloua gracilis), are present within the plant community, and can make up a large portion of the subdominant grass composition. Bristlecone pine (Pinus longaeva) and cliffrose (Purshia sp.) are also present and dominant on some ecological sites in the southern LRU, while they are sparse or absent in the northern LRU.
Ecological site concept
The Upland Shallow Hardpan (Singleleaf pinyon-Utah juniper) South site is located on upper fan remnants on gentle slopes (2 to 15 percent) between 5,800 and 7,000 feet (1,767 to 2,133 meters). The soil is shallow to a petrocalcic layer. The soil was formed in alluvium derived from igneous and sedimentary rock. The precipitation ranges from 12 to 17 inches (305 to 432 mm). The dominant vegetation is scattered singleleaf pinyon pine and Utah juniper with an understory of black sagebrush (Artemisia nova) or Wyoming big sagebrush (Artemisia tridentata subsp. wyomingensis) and bluebunch wheatgrass (Pseudoroegneria spicata). The plant composition by air-dry weight is about 40 percent grasses, 10 percent forbs, and 50 percent shrubs and trees. The relatively high value for tree cover (25 percent) will need to be evaluated. Much of the areas where this site has been mapped do not have trees or the trees have been mechanically removed. This site typically occurs upslope from Upland Gravelly Loam sites and downslope from Upland Stony Loam sites.
Associated sites
R028AB310UT Upland Loam (Bonneville big sagebrush) South
This site occurs lower on the landscape. This site also has fewer rock fragments on the soil surface and in the profile.
R028AB306UT Upland Gravelly Loam (Bonneville big sagebrush) South
This site occurs lower on the landscape.
Similar sites
F028AY099NV PIMO-JUOS/ARTRV/PSSPS-POFE
This site is similar in species composition and production, but has a shallow soil, steeper slope and is found higher in elevation. This site was developed in Nevada.
R028AY320UT Upland Shallow Hardpan (Pinyon-Utah Juniper)
This is a similar site that occurs in the Basin and Range North LRU and will not have as much influence from summer precipitation and will have fewer or no warm season species in the plant community.
R028AB338UT Upland Stony Loam (pinyon-Utah juniper) South
The soil has more rock fragments in the soil profile which effects the production of the site and can be found on steeper slopes.
R028AB324UT Upland Shallow Loam (Singleleaf pinyon-Utah juniper) South
This site is shallow to bedrock, not a petrocalcic layer.
R028AB334UT Upland Stony Loam (Wyoming sagebrush) South
This is a Wyoming big sagebrush site. The soils have more rock fragments.
Table 1. Dominant plant species
Tree (1) Pinus monophylla
(2) Juniperus osteospermaShrub (1) Artemisia nova
(2) Artemisia tridentata ssp. wyomingensisHerbaceous (1) Pseudoroegneria spicata
Physiographic features
The Upland Shallow Hardpan (Singleleaf pinyon-Utah juniper) South site occurs on fan remnants. This site is found on all aspects at elevations between 5,800 and 7,000 feet (1,767 to 2,133 meters). Slopes are gentle to slightly steep (2 to 15 percent). Runoff is low to very high and flooding/ponding do not occur on this site.
Table 2. Representative physiographic features
Landforms (1) Fan remnant
Flooding frequency None Ponding frequency None Elevation 5800 – 7000 ft Slope 2 – 15 % Aspect Aspect is not a significant factor Climatic features
The climate is characterized by warm, dry summers, cold, snowy winters and moist springs. The average annual precipitation is between 12 and 17 inches. October through May is the wettest part of the year and May and June are the driest. There are summer convective storms that occur beginning in July. These storms are intermittent and may not occur reliably every year, however they may provide enough summer moisture to alter the plant community with warm season grasses. The effective moisture for plant growth is the 62 percent that falls during the plant dormant period, which wets the soil deeply in the spring.
Table 3 Representative climatic features
Frost-free period (characteristic range) Freeze-free period (characteristic range) Precipitation total (characteristic range) 10-20 in Frost-free period (average) Freeze-free period (average) Precipitation total (average) 20 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Due to its landscape position, the Upland Shallow Hardpan (Singleleaf pinyon-Utah juniper) South site is not typically influenced by streams or wetlands. It can sometimes be influenced by overland flow during heavy thunder storms and/or during wetter spring runoff periods.
Soil features
The soils are shallow over an indurated petrocalcic layer and well drained. They typically have a pertrocalcic layer within 20 inches of the soil surface. They formed in alluvium derived from igneous and sedimentary rock. The surface horizon has cobbly loam textures and about 4 inches (10 cm) thick. About 35 percent of the soil surface is covered by rock fragments. The volume of rock fragments in the soil profile is 5 to 22 percent. Permeability is moderate. The soil moisture regime is xeric and the soil temperature regime is mesic.
Soil Map Units that may contain this site:
Soil Survey Area: Soil Components (Map units in parentheses)
Iron-Washington Area (UT634): Elenore (374); Pavant (445, 446, 447); Revor (463)
Beaver-Cove Fort Area (UT640): Black Ridge (BRF, POF2); Murdock (MYB, MZF2, USF); Oakden (FDF); Pavant (PdB, PEC, PFG); Phage (UTF2)Table 4. Representative soil features
Parent material (1) Alluvium – igneous and sedimentary rock
Surface texture (1) Cobbly loam
(2) Silt loam
Drainage class Well drained Permeability class Moderate Soil depth 10 – 20 in Surface fragment cover <=3" 0 – 29 % Surface fragment cover >3" 5 – 7 % Available water capacity
(Depth not specified)1.8 – 4.9 in Calcium carbonate equivalent
(Depth not specified)0 – 5 % Electrical conductivity
(Depth not specified)0 – 2 mmhos/cm Soil reaction (1:1 water)
(Depth not specified)7.4 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 5 % Subsurface fragment volume >3"
(Depth not specified)5 – 17 % Ecological dynamics
These plant communities may not represent every possibility, but they are the most prevalent and repeatable plant communities. As more data is collected, some of these plant communities may be revised or removed and new ones may be added. None of these plant communities should necessarily be thought of as the “desired plant community”. According to the USDA NRCS National Range and Pasture Handbook, the desired plant community will be determined by the decision makers and will meet minimum quality criteria established by the NRCS. The main purpose for including any description of a plant community here is to capture the current knowledge and experience at the time of this revision.
Utah juniper (Juniperus osteosperma) and singleleaf pinyon (Pinus monophylla) are the dominant tree species. This site is vulnerable to an increase in both pinyon and juniper trees without disturbances that keep the tree densities lower (i.e. fire). Singleleaf pinyon and Utah juniper may dominate the site if there is time without disturbances and eventually out-compete mountain big sagebrush for water and sunlight, severely reducing both the shrub and herbaceous understory (Miller et al. 2000, Lett and Knapp 2005). Bluegrasses may remain underneath trees on north-facing slopes. The potential for soil erosion increases as the Utah juniper woodland matures and the understory plant community cover declines (Pierson et al. 2010).
Fire Ecology:
Infilling by younger trees increases canopy cover causing a decrease in understory perennial vegetation and an increase in bare ground. As pinyon and juniper trees increase in density so has their litter. Phenolic compounds of juniper scales can have an inhibitory effect on grass growth (Jameson 1970). Furthermore, infilling shifts stand level biomass from ground fuels to canopy fuels which has the potential to significantly impact fire behavior. The more tree dominated pinyon and juniper woodlands become, the less likely they are to burn under moderate conditions, resulting in infrequent high intensity fires (Gruell 1999, Miller et al. 2008). Additionally, as the understory vegetation declines in vigor and density with increased canopy the seed and propagules of the understory plant community also decrease significantly. The increase in bare ground allows for the invasion of non-native annual species such as cheatgrass and with intensive wildfire the potential for conversion to annual exotics is a serious threat (Tausch 1999, Miller et al. 2008). The introduction of annual weedy species, like cheatgrass, may cause an increase in fire frequency and eventually lead to an annual dominated community (Miller et al. 2013). Infilling by singleleaf pinyon and Utah juniper may also occur with an extended fire return interval. Without fire or changes in management, pinyon and juniper will dominate the site and Bonneville big sagebrush will be severely reduced. The herbaceous understory will typically be reduced. The potential for soil erosion increases as the juniper woodland matures and the understory plant community cover declines. Catastrophic wildfire in juniper controlled sites may lead to an annual weed dominated site.
Livestock/Wildlife Grazing Interpretations:
Overgrazing leads to an increase in sagebrush and a decline in understory plants like bluebunch wheatgrass. Squirreltail will increase temporarily with further degradation. Invasion of annual weedy forbs and cheatgrass could occur with further grazing degradation, leading to a decline in squirreltail and an increase in bare ground. Wetter sites are more resistant to degradation and may end up having sagebrush and Sandberg bluegrass dominate the site. A combination of overgrazing and prolonged drought may lead to soil redistribution, increased bare ground and a loss in plant production. Bluebunch wheatgrass is moderately grazing tolerant but is very sensitive to defoliation during the active growth period (Blaisdell and Pechanec 1949, Laycock 1967, Anderson and Scherzinger 1975). Sandberg bluegrass may slow reestablishment of deeper rooted bunchgrass, increase under grazing pressure (Tisdale and Hironaka 1981) and is capable of co-existing with cheatgrass. Reduced bunchgrass vigor or density provides an opportunity for Sandberg bluegrass expansion and/or cheatgrass and other invasive species to occupy interspaces, leading to increased fire frequency and potentially an annual plant community. Depending on the season of use, the grazer and site conditions, either Sandberg bluegrass or cheatgrass may become the dominant understory with inappropriate grazing management. For example, Daubenmire (1970) found that heavy sheep grazing favors Sandberg bluegrass, while heavy cattle grazing favors cheatgrass.
Four possible alternative stable states have been hypothesized for this ecological site. This site is similar to 028AY099NV developed in Nevada. The state and transition model and narratives used from site 099NV and applied to Upland Shallow Hardpan (Singleleaf pinyon-Utah juniper) South site (Stringham et al. 2015). The Reference State contains four community phases, shrub/grass dominated, shrub dominated, grass dominated, and a fire tolerant phase. The primary drivers in this state are fire, drought, and/or insect of disease. The Current Potential State is like the Reference State; however, non-native species have been introduced in the system which alters the resilience and resistance of the state. The Tree State occurs when there has been sufficient time for junipers and/or pinyon trees to increase in density and dominate the site dynamics. The Seeded State occurs with management with seeding of deep rooted perennial bunchgrasses. An Annual State may occur, but has not been documented. Specific community phases and transitions will be described in the narratives below.State and transition model
Custom diagramStandard diagram
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
SWAPAEHSWAPAEHSWAPAEHSWAPAEHState 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Reference StateThe Reference State includes the plant communities that were best adapted to the unique combination of factors associated with this ecological site prior to European settlement. It was in a natural dynamic equilibrium with the historic biotic, abiotic, climatic factors on its ecological site in North America at the time of European immigration and settlement. The dominant aspect of the plant community is pinyon pine, Utah juniper, and mountain big sagebrush. The composition by air-dry weight is approximately 15 percent trees, 35 percent perennial grasses, 10 percent forbs, and 40 percent shrubs.
Characteristics and indicators. This state will not include any non-native species in the plant community.
Community 1.1
Old growth trees/mountain big sagebrush/bluebunch wheatgrassThis community phase will have widely scattered old trees with a shrub/grass understory. The dominant visual aspect of the plant community is singleleaf pinyon/Utah juniper which make up about 15 percent of the canopy cover. Trees will be rounded or flat topped. Bluebunch wheatgrass and Indian ricegrass are the dominant understory.
Figure 3. 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 120 280 380 Tree 75 175 238 Shrub/Vine 75 175 238 Forb 30 70 95 Total 300 700 951 Table 6. Ground cover
Tree foliar cover 20% Shrub/vine/liana foliar cover 20-30% Grass/grasslike foliar cover 10-30% Forb foliar cover 0-10% Non-vascular plants 0% Biological crusts 0% Litter 0% Surface fragments >0.25" and <=3" 0% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 0% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – – – >0.5 <= 1 – – – – >1 <= 2 – 25-35% 20-30% 0-10% >2 <= 4.5 – – – – >4.5 <= 13 10-20% – – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Community 1.2
Bluebunch wheatgrass/pinyon and juniper seedlings/shrubsThis community phase is characterized by a post-fire shrub and herbaceous community. Bluebunch wheatgrass and other perennial grasses dominate. Forbs may increase post-fire but will likely return to pre-burn levels within a few years. Singleleaf pinyon and Utah juniper seedlings up to 20 inches in height may be present. Mountain big sagebrush may be present in unburned patches. Burned tree skeletons may be present; however, these have little or no effect on the understory vegetation.
Community 1.3
Pinyon and juniper, young trees/perennial bunchgrasses/shrubsThis community phase is characterized as an immature woodland with pinyon, juniper trees averaging over 4 feet in height. Pinyon and juniper canopy cover is 10 to 20 percent. Tree crowns are typically cone- or pyramidal-shaped. Understory vegetation consists of smaller tree seedling and saplings, as well as perennial bunchgrasses, and sagebrush.
Community 1.4
Pinyon and juniper multiple age classes/perennial bunchgrasses/shrubs (at-risk)This phase is dominated by Utah juniper and singleleaf pinyon. The stand exhibits mixed age classes and canopy cover exceeds 20 percent. The density and vigor of the mountain big sagebrush and perennial bunchgrass understory is decreased. Bare ground areas are likely to increase. Mat-forming forbs may increase. This community is at risk of crossing a threshold; without proper management this phase will transition to the infilled woodland state 3. This community phase is typically described as early Phase II woodland (Miller et al. 2008).
Pathway 1.1a
Community 1.1 to 1.2A high severity crown fire will eliminate or reduce the singleleaf pinyon and Utah juniper overstory and the shrub component. This allows the perennial bunchgrasses to increase.
Pathway 1.1b
Community 1.1 to 1.4Time without disturbance such as fire, long-term drought, or disease will allow gradual infilling of the trees.
Pathway 1.2a
Community 1.2 to 1.3Time without disturbance such as fire, long-term drought, or disease will allow for the gradual maturation of the singleleaf pinyon and Utah Juniper component. Mountain big sagebrush reestablishes. Excessive herbivory may also reduce perennial grass understory.
Pathway 1.3a
Community 1.3 to 1.1Fire reduces or eliminates tree canopy, allowing perennial grasses to dominate the site.
Pathway 1.3b
Community 1.3 to 1.2Time without disturbance such as fire, long-term drought, or disease will allow for the gradual maturation of singleleaf pinyon and Utah juniper. Infilling by younger trees continues.
Pathway 1.4a
Community 1.4 to 1.1Low intensity fire, insect infestation, or disease kills individual trees within the stand reducing canopy cover to less than 20 percent. Over time young trees mature to replace and maintain the old-growth woodland. The mountain big sagebrush and perennial bunchgrass community increases in density and vigor.
Pathway 1.4b
Community 1.4 to 1.2A high-severity crown fire will eliminate or reduce the singleleaf pinyon and Utah juniper overstory and the shrub component which will allow for the perennial bunchgrasses to dominate the site.
State 2
Current Potential StateThe Current Potential State is similar to the Reference State 1, with four general community phases: an old-growth woodland phase, a shrub-herbaceous phase, an immature tree phase, and an infilled tree phase. Ecological function has not changed; however the resiliency of the state has been reduced by the presence of non-native species. These non-natives, particularly cheatgrass, can be highly flammable and promote fire where historically fire had been infrequent. Negative feedbacks enhance ecosystem resilience and contribute to the stability of the state. These include the presence of all structural and functional groups, low fine fuel loads and retention of organic matter and nutrients. Positive feedbacks decrease ecosystem resilience and stability of the state. These include the nonnatives’ high seed output, persistent seed bank, rapid growth rate, ability to cross pollinate, and adaptations for seed dispersal. Fires within this community with the small amount of non-native annual species present are likely still small and patchy due to low fuel loads. This fire type will create a plant community mosaic that will include all/most of the following community phases within this state.
Characteristics and indicators. This state will be similar to the Reference state except it will have non-native species in the plant communities.
Community 2.1
Old growth singleleaf pinyon and Utah juniper/sagebrush/bluebunch wheatgrassThis phase is characterized by a widely dispersed old-growth Utah juniper and singleleaf pinyon trees with an understory of mountain big sagebrush and perennial bunchgrasses. The visual aspect is dominated by singleleaf pinyon and Utah juniper which make up 10-25 percent of the overstory canopy cover. Trees have reached maximal or near maximal heights for the site and many tree crowns may be flat- or round-topped. Bluebunch wheatgrass and Indian ricegrass are the most prevalent grasses in the understory. Mountain big sagebrush is the primary understory shrub. Forbs, such as arrowleaf balsamroot, are minor components. Ground fires within this community are infrequent occurring on average every 15 to 25 years. This fire type will create a plant community mosaic that will include all/most of the following community phases within this state. Annual non-native species are present in trace amounts.
Community 2.2
Bluebunch wheatgrass/pinyon and juniper seedlings/shrubsThis community phase is characterized by a post-fire shrub and herbaceous community. Bluebunch wheatgrass and other perennial grasses dominate. Forbs may increase post-fire but will likely return to pre-burn levels within a few years. Pinyon and juniper seedlings up to 20 inches in height may be present. Mountain big sagebrush may be present in unburned patches. Burned tree skeletons may be present; however, these have little or no effect on the understory vegetation. Annual non-native species generally respond well after fire and may be stable or increasing within the community.
Community 2.3
Pinyon and juniper young trees/perennial bunchgrasses/shrubsThis community phase is characterized by an immature woodland, with singleleaf pinyon and Utah juniper trees averaging over 4 feet in height. Tree canopy cover is between 10 to 20 percent. Tree crowns are typically cone- or pyramidal-shaped. Understory vegetation consists of smaller tree seedling and saplings, as well as perennial bunchgrasses and shrubs. Annual nonnative species are present.
Community 2.4
Pinyon and juniper multiple age classes/perennial bunchgrasses/shrubs (at-risk)This phase is dominated by singleleaf pinyon and Utah juniper. The stand exhibits mixed age classes and canopy cover exceeds 20 percent. The density and vigor of the mountain big sagebrush and perennial bunchgrass understory is decreased. Bare ground areas are likely to increase. Mat-forming forbs may increase. Annual non-native species are present primarily under tree canopies. This community is at risk of crossing a threshold, without proper management this phase will transition to the infilled tree state 3. This community phase is typically described as early Phase II woodland (Miller et al. 2008).
Pathway 2.1a
Community 2.1 to 2.2A high-severity crown fire will eliminate or reduce the singleleaf pinyon and Utah juniper overstory and the shrub component. This allows for the perennial bunchgrasses to dominate the site.
Pathway 2.1b
Community 2.1 to 2.4Time without disturbance such as fire, long-term drought, or disease will allow for the gradual infilling of singleleaf pinyon and Utah juniper.
Pathway 2.2a
Community 2.2 to 2.3Time without disturbance such as fire, long-term drought, or disease will allow for the gradual maturation of the singleleaf pinyon and Utah Juniper component. Mountain big sagebrush reestablishes. Excessive herbivory may also reduce perennial grass understory.
Pathway 2.3a
Community 2.3 to 2.1Time without disturbance such as fire, long-term drought, or disease will allow for the gradual maturation of singleleaf pinyon and Utah juniper. Infilling by younger trees continues.
Pathway 2.3b
Community 2.3 to 2.2Fire reduces or eliminates tree canopy, allowing perennial grasses to dominate the site.
Pathway 2.4a
Community 2.4 to 2.1Low intensity fire, insect infestation, or disease kills individual trees within the stand reducing canopy cover to less than 20 percent. Over time young trees mature to replace and maintain the old-growth woodland. The mountain big sagebrush and perennial bunchgrass community increases in density and vigor. Annual non-natives present in trace amounts.
Pathway 2.4b
Community 2.4 to 2.2A high-severity crown fire will eliminate or reduce the singleleaf pinyon and Utah juniper overstory and the shrub component which will allow for the perennial bunchgrasses to dominate the site. Annual non-native grasses typically respond positively to fire and may increase in the post-fire community.
State 3
Infilled Tree StateThe Infilled Tree State has two community phases that are characterized by the dominance of Utah juniper and singleleaf pinyon in the overstory. This state is identifiable by over 30 percent cover of Utah juniper and singleleaf pinyon. This stand exhibits a mixed age class. Older trees are at maximal height and upper crowns may be flat-topped or rounded. Younger trees are typically cone- or pyramidal shaped. Understory vegetation is sparse due to increasing shade and competition from trees.
Community 3.1
Pinyon and juniper/invasive annuals/native perennials and shrubsSingleleaf pinyon and Utah juniper dominate the aspect. Understory vegetation is thinning. Perennial bunchgrasses are sparse and mountain big sagebrush skeletons are as common as live shrubs due to tree competition for soil water, overstory shading, and duff accumulation. Tree canopy cover is greater than 30 percent. Annual non-native species are present or co-dominate in the understory. Bare ground areas are prevalent. This community phase is typically described as a Phase II woodland (Miller et al. 2008).
Community 3.2
Pinyon and juniper/invasive annualsSingleleaf pinyon and Utah juniper dominate the aspect. Tree canopy cover exceeds 30 percent and may be as high as 50 percent. Understory vegetation is sparse to absent. Perennial bunchgrasses, if present exist in the dripline or under the canopy of trees. Mountain sagebrush skeletons may be present or absent. Mat-forming forbs or Sandberg’s bluegrass may dominate interspaces. Annual nonnative species are present and are typically found under the trees. Bare ground areas are large and interconnected. Soil redistribution may be extensive. This community phase is typically described as a Phase III woodland (Miller et al. 2008).
Pathway 3.1a
Community 3.1 to 3.2Time without disturbance such as fire, long-term drought, or disease will allow for the gradual maturation of singleleaf pinyon and Utah juniper. Infilling by younger trees continues.
State 4
Seeded StateThe Seeded State is characterized by the dominance of perennial non-native species such as crested wheatgrass (Agropyron cristatum). Wyoming big sagebrush or rabbitbrush may dominate the overstory. Annual non-native species may be present in the community.
Community 4.1
Introduced non-native bunchgrasses/native shrubsCrested wheatgrass dominates the plant community with native shrubs. Annual non-native species may be present.
Transition T1A
State 1 to 2Trigger: Introduction of non-native annual species Slow variables: Over time the annual non-native plants will increase within the community. Threshold: Any amount of introduced non-native species causes an immediate decrease in the resilience of the site. Annual non-native species cannot be easily removed from the system and have the potential to significantly alter disturbance regimes from their historic range of variation.
Transition T1B
State 1 to 3Trigger: Time and a lack of disturbance allow trees to dominate site resources; may be coupled with inappropriate grazing management that favors shrub and tree dominance. Slow variables: Over time the abundance and size of trees will increase. Threshold: Juniper and pinyon canopy cover is greater than 30 percent. Little understory vegetation remains due to competition with trees for site resources.
Transition T2A
State 2 to 3Trigger: Time and a lack of disturbance allow trees to dominate site resources; may be coupled with inappropriate grazing management that favors shrub and tree dominance. Slow variables: Over time the abundance and size of trees will increase. Threshold: Juniper and pinyon canopy cover is greater than 30 percent. Little understory vegetation remains due to competition with trees for site resources
Transition T2B
State 2 to 4Mechanical treatment of trees.
Restoration pathway R4A
State 3 to 2Manual or mechanical thinning of trees coupled with seeding. Probability of success is highest from community phase 3.1.
Transition T3A
State 3 to 4Thinning of trees coupled with seeding. Success unlikely from phase 3.2.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Shrub/Vine0 Primary Shrubs 240–400 black sagebrush ARNO4 Artemisia nova 120–160 – Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 40–80 – Mexican cliffrose PUME Purshia mexicana 40–80 – antelope bitterbrush PUTR2 Purshia tridentata 40–80 – 3 Secondary Shrubs 24–40 yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 8–24 – Nevada jointfir EPNE Ephedra nevadensis 8–16 – broom snakeweed GUSA2 Gutierrezia sarothrae 8–16 – stemless mock goldenweed STAC Stenotus acaulis 8–16 – mountain snowberry SYOR2 Symphoricarpos oreophilus 8–16 – shadscale saltbush ATCO Atriplex confertifolia 8–16 – Grass/Grasslike0 Primary Grasses 232–360 bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 80–120 – Indian ricegrass ACHY Achnatherum hymenoides 80–120 – squirreltail ELEL5 Elymus elymoides 24–40 – needle and thread HECO26 Hesperostipa comata 24–40 – 1 Secondary Grasses 24–40 prairie Junegrass KOMA Koeleria macrantha 8–24 – western wheatgrass PASM Pascopyrum smithii 8–24 – Sandberg bluegrass POSE Poa secunda 8–24 – sand dropseed SPCR Sporobolus cryptandrus 8–24 – Forb2 Forbs 80–120 freckled milkvetch ASLE8 Astragalus lentiginosus 8–24 – Hooker's balsamroot BAHO Balsamorhiza hookeri 8–24 – tapertip hawksbeard CRAC2 Crepis acuminata 8–24 – roundspike cryptantha CRHU2 Cryptantha humilis 8–24 – cushion buckwheat EROV Eriogonum ovalifolium 8–24 – ballhead ipomopsis IPCOC3 Ipomopsis congesta ssp. congesta 8–24 – low beardtongue PEHU Penstemon humilis 8–24 – spiny phlox PHHO Phlox hoodii 8–24 – gooseberryleaf globemallow SPGR2 Sphaeralcea grossulariifolia 8–24 – Pacific aster SYCHC Symphyotrichum chilense var. chilense 8–24 – Tree4 Trees 104–160 singleleaf pinyon PIMO Pinus monophylla 80–120 – Utah juniper JUOS Juniperus osteosperma 24–40 – Table 9. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 1.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 1.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 12. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 13. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 14. Community 2.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 15. Community 2.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 16. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 17. Community 3.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 18. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Inventory data references
The data for this site consists of 22 417s (double sampling) from 1963-1978, 9 UT-2s (ocular estimates) from 1974 to 1981, 4 Wood-1 forms from 1978 and 1 line-point intercept from 2007.
Other references
Anderson, E. W. and R. J. Scherzinger. 1975. Improving quality of winter forage for elk by cattle grazing. Journal of Range Management:120-125.
Blaisdell, J.P. and J.F. Pechanec. 1949. Effects of herbage removal at various dates on vigor of bluebunch wheatgrass and arrowleaf balsamroot. Ecology 30(3):298-305.
Daubenmire, R. 1970. Steppe Vegetation of Washington. 131 pp.
Gruell, G.E. 1999. Historical and modern roles of fire in pinyon-juniper. In: S. B. Monsen, R. Stevens [comps.] Proceedings: ecology and management of pinyon–juniper communities within the Interior West. RMRS-P-9. Ogden, UT, USA: US Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 24-28.
Jameson, D.A. 1970. Degradation and accumulation on inhibitory substances from Juniperus osteosperma (Torr.) Little. Plant Soil 33: 213-224.
Laycock, W. A. 1967. How heavy grazing and protection affect sagebrush-grass ranges. Journal of Range Management:206-213.
Lett, M. S., and A. K. Knapp. 2005. Woody plant encroachment and removal in mesic grassland: Production and composition responses of herbaceous vegetation. American Midland Naturalist 153:217-231.
Miller, R.F., J.C. Chambers, D.A. Pyke, F.B. Pierson, and C.J. Williams. 2013. A review of fire effects on vegetation and soils in the Great Basin Region: response and ecological site characteristics. Gen. Tech. Rep. RMRS-GTR-308. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 126 p.
Miller, R. F., T. J. Svejcar, and J. A. Rose. 2000. Impacts of western juniper on plant community composition and structure. Journal of Range Management:574-585.
Miller, R.F. R.J. Tasuch, E.D. McArthur, D.D. Johnson and S.C. Sanderson. 2008. Age Structure and Expansion of Pinon-Juniper Woodlands: A Regional Perspective in the Intermountain West. Res. Pap. RMRS-RP-69. Fort Collins CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 15
Pierson, F. B., C. J. Williams, P. R. Kormos, S. P. Hardegree, P. E. Clark, and B. M. Rau. 2010. Hydrologic vulnerability of sagebrush steppe following pinyon and juniper encroachment. Rangeland Ecology & Management 63:614-629.
Tausch, R. J. 1999. Historic pinyon and juniper woodland development. In: S. B. Monsen, R. Stevens [comps.] Proceedings ecology and management of pinyon-juniper communities within the Interior West; 1997 September 15-18. RMRS-P-9. US Department of Agriculture, Forest Service, Rocky Mountain Research Station Proceedings. p. 12-19.
Tisdale, E. W. and M. Hironaka. 1981. The sagebrush-grass region: A review of the ecological literature. University of Idaho, Forest, Wildlife and Range Experiment Station.Contributors
David J. Somorville
T. Stringham
P. Novak-EchiniqueApproval
Kendra Moseley, 6/12/2025
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 06/28/2026 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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PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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