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MLRA notes
Major Land Resource Area (MLRA): 028A–Ancient Lake Bonneville
MLRA 28A occurs in Utah (82%), Nevada (16%), and Idaho (2%). It makes up about 36,775 square miles (95,300 square kilometers). About three-fifths of this area is federally owned land, large tracts of which are used for military training and testing purposes by the. 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. They are not well dissected because of low rainfall in the MLRA. Most of the valleys are closed basins containing sinks or playa lakes. Elevation ranges from 3,950 to 6,560 feet (1,205 to 2,000 meters) in the basins and from 6,560 to 11,150 feet (2,000 to 3,400 meters) in the mountains.
Most of this area has alluvial valley fill and playa lakebed deposits at the surface. Great Salt Lake is all that remains of glacial Lake Bonneville, which covered this area during the most recent ice age. A level line on some mountain slopes indicates the former extent of this glacial lake. The uplifted mountains have exposed some Precambrian rocks at their margins. Most of the mountains in the interior of this area consist of tilted blocks of marine sediments from Cambrian to Mississippian age. Scattered outcrops of Tertiary continental sediments and volcanic rocks are throughout the area.
The average annual precipitation is 5 to 12 inches (125 to 305 millimeters) in the valleys and is as much as 49 inches (1,245 millimeters) in the mountains. Most of the rainfall occurs as high-intensity, convective thunderstorms during the growing season. The driest period is from midsummer to early autumn. Precipitation in winter typically occurs as snow. The average annual temperature is 39 to 53 degrees F (4 to 12 degrees C). The freeze-free period averages 165 days and ranges from 110 to 215 days, decreasing in length with elevation.
The dominant soil orders in this MLRA are Aridisols, Entisols, and Mollisols. The soils in the area dominantly have a mesic or frigid soil temperature regime, an aridic or xeric soil moisture regime, and mixed mineralogy. They generally are well drained or somewhat excessively drained, loamy or loamy-skeletal, and very deep.
Ecological site concept
This forest site occurs on sideslopes of mountains and hills on all exposures. Slopes range from 2 to 75 percent, but slopes of 15 to 50 percent are most typical. Elevations range from 6000 to 8400 feet.
Average annual precipitation is 10 to 14 inches. Mean annual air temperature is 45 to 49 degrees F. The average growing season is 85 to 100 days.
Soils associated with this site are very shallow to moderately deep ranging from 4 to 40 inches. They have formed in alluvium with mixed parent materials. Soil reaction is mostly mildly to strongly alkaline, and the soils are highly calcareous. Available water holding capacity is low to very low. These soils normally have high amounts of gravels, stones or cobbles on the surface that occupy plant growing space, yet help to reduce evaporation and conserve soil moisture.
The reference state is dominated by singleleaf pinyon and Utah juniper. Black sagebrush is the principal understory shrub. Bluebunch wheatgrass, Indian ricegrass, and bluegrasses are the most prevalent understory grasses. An overstory canopy of 20 to 30 percent is assumed to be representative of tree dominance on this site in the pristine environment. Wildfire is recognized as a natural disturbance that strongly influenced the structure and composition of the vegetation of this forest site. Overstory tree canopy composition is about 50 to 70 percent Utah juniper and about 30 to 50 percent singleleaf pinyon. Understory production ranges from 250 to 500 pounds per acre.
Similar sites
F028AY076NV PIMO/ARTRV/PSSPS-POFE
Mountain big sagebrush dominant understory shrub. Lower site index.
F028AY041NV JUOS/ARNO4/ACHY
Lower site index. Pinyon is a minor component in the overstory. Less productive understory.
Table 1. Dominant plant species
Tree (1) Pinus monophylla
(2) Juniperus osteospermaShrub (1) Artemisia nova
Herbaceous (1) Pseudoroegneria spicata
(2) Achnatherum hymenoidesPhysiographic features
This forest site occurs on sideslopes of mountains and hills on all exposures. Slopes range from 2 to 75 percent, but slopes of 15 to 50 percent are most typical. Elevations are 6000 to 8400 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain
(2) Mountain slope
(3) Hill
Elevation 6000 – 8400 ft Slope 2 – 75 % Aspect Aspect is not a significant factor Climatic features
Nevada’s climate is predominantly arid, with large daily ranges of temperature, infrequent severe storms, heavy snowfall in the higher mountains, and great location variations with elevation. Three basic geographical factors largely influence Nevada’s climate: continentality, latitude, and elevation. Continentality is the most important factor. The strong continental effect is expressed in the form of both dryness and large temperature variations. Nevada lies on the eastern, lee side of the Sierra Nevada Range, a massive mountain barrier that markedly influences the climate of the State. The prevailing winds are from the west, and as the warm moist air from the Pacific Ocean ascend the western slopes of the Sierra Range, the air cools, condensation occurs and most of the moisture falls as precipitation. As the air descends the eastern slope, it is warmed by compression, and very little precipitation occurs. The effects of this mountain barrier are felt not only in the West but throughout the state, with the result that the lowlands of Nevada are largely desert or steppes. The temperature regime is also affected by the blocking of the inland-moving maritime air. Nevada sheltered from maritime winds, has a continental climate with well-developed seasons and the terrain responds quickly to changes in solar heating.
Nevada lies within the mid-latitude belt of prevailing westerly winds which occur most of the year. These winds bring frequent changes in weather during the late fall, winter and spring months, when most of the precipitation occurs. To the south of the mid-latitude westerlies, lies a zone of high pressure in subtropical latitudes, with a center over the Pacific Ocean. In the summer, this high-pressure belt shifts northward over the latitudes of Nevada, blocking storms from the ocean. The resulting weather is mostly clear and dry during the summer and early fall, with scattered thundershowers. The eastern portion of the state receives significant summer thunderstorms generated from monsoonal moisture pushed up from the Gulf of California, known as the North American monsoon. The monsoon system peaks in August and by October the monsoon high over the Western U.S. begins to weaken and the precipitation retreats southward towards the tropics (NOAA 2004).
Over 50% of the precipitation occurs during spring and summer (March through August). Average annual precipitation ranges from 10 to 14 inches. At the Great Basin NP climate station (263340), the mean annual precipitation is approximately 13.33 inches and the mean annual air temperature is 48.2 degrees F. The average growing season is approximately 100 to 140 days.
Mean precipitation by month (Great Basin NP): Jan 1.05; Feb 1.18; Mar 1.37; Apr 1.21; May 1.24; Jun 0.87; Jul 0.97; Aug 1.18; Sept 1.08; Oct 1.24; Nov 0.97; Dec 0.96.Table 3 Representative climatic features
Frost-free period (average) 110 days Freeze-free period (average) 150 days Precipitation total (average) 10 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
Figure 3. Annual precipitation pattern
Figure 4 Annual average temperature pattern
Climate stations used
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(1) GREAT BASIN NP [USC00263340], Baker, NV
">Influencing water features
There are no influencing water features associated with this site.
Soil features
Soils associated with this site are typically very shallow to moderately deep with depth to bedrock ranging from 4 to 40 inches. They have formed in alluvium with mixed parent material origin. Soil reaction is mostly mildly to strongly alkaline, and some soils are highly calcareous. Available water holding capacity is low to very low. These soils normally have high amounts of gravels, stones or cobbles on the surface that occupy plant growing space, yet help to reduce evaporation and conserve soil moisture. Rock fragments on the surface provide a stabilizing affect on surface erosion conditions. Some soils may have a thin, weak mollic epipedon. Runoff is medium to very high. The soil temperature regime is mesic and the soil moisture regime is aridic bordering on xeric. The soil series associated with this site include: Basket, Bellehelen, Cedarcabin, Decathon, Homestake, Hopeka, Lodar, Logring, Nuhelen, Pioche, and Udel.
The representative soil series is Lodar, classified as a Loamy-skeletal, carbonatic, mesic Lithic Calcixerolls. Diagnostic horizons include a mollic epipedon from the soil surface to 7 inches and a calcic horizon of carbonate accumulation from 7 to 15 inches. Clay content in the particle control section averages 18 to 27 percent. Rock fragments range from 20 to 80 percent by volume but averages more than 35 percent between 10 inches and bedrock. Reaction is slightly to strongly alkaline. Effervescence is slightly or strongly effervescent. Lithology consists of residuum and colluvium derived from limestone and sandstone.Table 4. Representative soil features
Parent material (1) Alluvium – limestone
(2) Residuum – sandstone
(3) Colluvium – welded tuff
Surface texture (1) Very cobbly loam
(2) Very gravelly sandy loam
(3) Very gravelly sandy loam
Family particle size (1) Loamy
Drainage class Well drained to excessively drained Permeability class Slow to moderately rapid Soil depth 4 – 40 in Surface fragment cover <=3" 20 – 40 % Surface fragment cover >3" 1 – 30 % Available water capacity
(0-40in)0.3 – 3.8 in Calcium carbonate equivalent
(0-40in)0 – 60 % Electrical conductivity
(0-40in)0 – 4 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-40in)6.6 – 8 Subsurface fragment volume <=3"
(Depth not specified)20 – 80 % Subsurface fragment volume >3"
(Depth not specified)2 – 45 % Ecological dynamics
An ecological site is the product of all the environmental factors responsible for its development and it has a set of key characteristics that influence a site’s resilience to disturbance and resistance to invasives. Key characteristics include 1) climate (precipitation, temperature), 2) topography (aspect, slope, elevation, and landform), 3) hydrology (infiltration, runoff), 4) soils (depth, texture, structure, organic matter), 5) plant communities (functional groups, productivity), and 6) natural disturbance regime (fire, herbivory, etc.) (Caudle et al 2013). Biotic factors that influence resilience include site productivity, species composition and structure, and population regulation and regeneration (Chambers et al. 2013).
Pinyon and juniper dominated plant communities in the cold desert of the Intermountain West occupy over 18 million ha (44,600,000 acres) (Miller and Tausch 2001). In the mid to late 1900’s, the number of pinyon and juniper trees establishing per decade began to increase compared to the previous several hundred years. The substantial increase in conifer establishment is attributed to a number of factors, the most important being: (1) cessation of the aboriginal burning (Tausch 1999), (2) change in climate with rising temperatures (Heyerdahl et al. 2006), (3) the reduced frequency of fire likely driven by the introduction of domestic livestock, (4) a decrease in wildfire frequency along with improved wildfire suppression efforts and (5) potentially increased CO2 levels favoring woody plant establishment (Tausch 1999, Bunting 1994). Miller et al. (2008) found presettlement tree densities averaged 2 to 11 per acre in six woodlands studied across the Intermountain West. Current stand densities range from 80 to 358 trees/ac. In Utah, Nevada, and Oregon, trees established prior to 1860 account for only 2 percent or less of the total population of pinyon and juniper (Miller et al. 2008). The research strongly suggests that for over 200 years prior to settlement, woodlands in the Great Basin were relatively low density with limited rates of establishment (Miller et al. 2008, Miller and Tausch 2001). Tree canopy cover of 10 to 20% may be more representative of these sites in pristine condition. Increases in pinyon and juniper densities post-settlement were the result of both infill in mixed age tree communities and expansion into shrub-steppe communities. Pre-settlement trees accounted for less than two percent of the stands sampled in Nevada, Oregon and Utah (Miller et al. 2008, Miller and Tausch 2001, Miller et al. 1999). However, the proportion of old-growth can vary depending on disturbance regimes, soils and climate. Some ecological sites are capable of supporting persistent woodlands, likely due to specific soils and climate resulting in infrequent stand replacement disturbance regimes. In the Great Basin, old-growth trees have been found to typically grow on rocky shallow or sandy soils that support little understory vegetation to carry a fire (Holmes et al. 1986, Miller and Rose 1995, West et al. 1998).
Singleleaf pinyon and Utah juniper are long-lived tree species with wide ecological amplitudes (Tausch et al 1981, Weisberg and Dongwook 2012, West et al 1998). Maximum ages of pinyon and juniper exceed 1000 years and stands with maximum age classes are only found on steep rocky slopes with no evidence of fire (West et al 1975). Singleleaf pinyon is slow-growing and very intolerant to shade with the exception of young plants, usually first year seedlings (Tueller and Clark 1975). Singleleaf pinyon seedling establishment is episodic. Population age structure is affected by drought, which reduces seedling and sapling recruitment more than other age classes. The ecotones between singleleaf pinyon woodlands and adjacent shrublands and grasslands provide favorable microhabitats for singleleaf pinyon seedling establishment since they are active zones for seed dispersal, nurse plants are available, and singleleaf pinyon seedlings are only affected by competition from grass and other herbaceous vegetation for a couple of years.
Juniper litter has an allelopathic effect on some understory species, especially Sandberg bluegrass, and blue grama. This effect is particularly evident on heavy, poorly drained clay soils. Broadcasting grass seeds over litter appeared to lower the allelopathic effects.
Pinyon and juniper growth is dependent mostly upon soil moisture stored from winter precipitation, mainly snow. Much of the summer precipitation is ineffective, being lost in runoff after summer convection storms or by evaporation and interception (Tueller and Clark 1975). Pinyon and juniper are highly resistant to drought which are common in the Great Basin. Tap roots of pinyon and juniper have a relatively rapid rate of root elongation and are thus able to persist until precipitation conditions are more favorable (Emerson 1932).
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).
Specific successional pathways after disturbance in pinyon-juniper stands are dependent on a number of variables such as plant species present at the time of disturbance and their individual responses to disturbance, past management, type and size of disturbance, available seed sources in the soil or adjacent areas, and site and climatic conditions throughout the successional process.
Utah juniper can be killed by a fungus called Juniper Pocket Rot (Pyrofomes demidoffi), also known as white truck rot (Eddleman et al. 1994 and Durham 2014). Pocket rot enters the tree through any wound or opening that exposes the heartwood. In an advanced stage, this fungus can cause high mortality (Durham 2014). Dwarf mistletoe (Phorandendron spp.) a parasitic plant, may also affect Utah juniper and without treatment or pruning, may kill the tree 10-15 years after infection. Seedlings and saplings are most susceptible to the parasite (Christopherson 2014). Other diseases capable of affecting juniper include: witches’-broom (Gymnosporangium sp.), which may girdle and kill branches; leaf rust (Gymnosporangium sp.) on leaves and young branches; and juniper blight (Phomopsis sp.). Insections include: flat-head borers (Chrysobothris sp.) that attack the wood; long-horned beetles (Methia juniper, Styloxus bicolor) that girdle limbs and twigs; and round-head borers (Callidium spp.) that attack twigs and limbs (Tueller and Clark 1975).
Phillips (1909) recognized that the pinyons are more resistant to disease than most of the conifers with which it associates. Hepting (1971) lists several diseases affecting pinyon including: foliage diseases, a tarspot needle cast, stem diseases such as blister rust and dwarf mistletoe, root diseases and trunk rots, red heart rot, and but rot. The pinyon ips beetle (Ips confuses) and pinyon needle scale (Matsucoccus acalyptus) are both native insects to Nevada that attack pinyon pines throughout their range. The pinyon needle scale weakens trees by killing needles older than one year. Sometimes small trees are killed by repeated feeding and large trees are weakened to the point that they are attacked by the pinyon ips beetle. The beetle typically kills weak and damaged trees (Phillips 2014). During periods of chronic drought the impact of these two insects on singleleaf pinyon can be substantial.
Black sagebrush, the dominant shrub on this site, is generally long-lived; therefore it is not necessary for new individuals to recruit every year for perpetuation of the stand. Infrequent large recruitment events and simultaneous low, continuous recruitment is the foundation of population maintenance (Noy-Meir 1973). Survival of the seedlings is dependent on adequate moisture conditions.
The perennial bunchgrasses that are co-dominant with the shrubs include Indian ricegrass, bluebunch wheatgrass, muttongrass, and Sandberg’s bluegrass. These species generally have somewhat shallower root systems than the shrubs, but root densities are often as high as or higher than those of shrubs in the upper 0.5 m of the soil profile. General differences in root depth distributions between grasses and shrubs results in resource partitioning in these shrub/grass systems.
This ecological site has low to moderate resilience to disturbance and resistance to invasion. Resilience increases with elevation, aspect, increased precipitation and increased nutrient availability. Four possible alternative stable states have been identified for this site.
Fire Ecology:
Lightning-ignited fires were common but typically did not affect more than a few individual trees. Replacement fires were uncommon to rare (100-600 years) and occurred primarily during extreme fire behavior conditions. Spreading, low-intensity surface fires had a very limited role in molding stand structure and dynamics. Surface spread was more likely to occur in higher-density woodlands growing on more productive sites (Romme et al 2007). Pre-settlement fire return intervals in the Great Basin National Park, Nevada, were found to have a mean range between 50 to 100 years with north-facing slopes burning every 15 to 20 years and rocky landscapes with sparse understory very infrequently (Gruell 1999). Woodland dynamics are largely attributed to long-term climatic shifts (temperature, amounts and distribution of precipitation) and the extent and return intervals of fire (Miller and Tausch 2001). Limited data exists that describes fire histories across woodlands in the Great Basin. The infilling of younger trees into the old-growth stands and the expansion of trees into the surrounding sagebrush steppe ecological sites has increased the risk of loss of pre-settlement trees due to increased fire severity and size resulting from the increase in the abundance and landscape level continuity of fuels (Miller et al. 2008).
Utah juniper is usually killed by fire, and is most vulnerable to fire when it is under four feet tall (Bradley et al. 1992). Because they have foliage farther from the ground and thicker bark, larger trees can survive low severity fires but mortality does occur when 60% or more of the crown is scorched (Bradley et al. 1992). Singleleaf pinyons are also most vulnerable to fire when less than four feet tall, however mature trees do not self-prune their dead branches allowing for accumulated fuel in the crowns. This characteristic and the relative flammability of the foliage make individual mature trees susceptible to fire (Bradley et al. 1992). With the low production of the understory vegetation and low density of trees per acre, high severity fires within this plant community were not likely and rarely became crown fires (Bradley et al. 1992, Miller and Tausch 2001).
Singleleaf pinyon and juniper reestablish by seed from nearby seed sources or surviving seeds. Junipers have a long-lived seed bank due to delayed germination by impermeable seed coats, immature or dormant embryos and germination inhibitors (Chambers et al. 1999). Singleleaf pinyon trees have relatively short-lived seeds with little innate dormancy that form only temporary seed banks with most seeds germinating the spring following dispersal (Meewig and Bassett 1983). Density of pinyon seeds in the seed bank is dependent upon the current year’s cone crop. Singleleaf pinyon are known to have favorable cone production every two to three years thus the potential for a large temporary seed bank is high during mast years and likely low during non-mast years (Chambers et al. 1999). The role of nurse plant requirements between the two tree species is important to post-fire establishment. Chambers et al. (1999) found that singleleaf pinyon seedlings rarely establish in interspaces or open environments. In contrast, Utah juniper seedlings were found capable of establishing in interspace microhabitats as frequently as under sagebrush. Therefore, fire that removes both trees and understory shrubs in pinyon-juniper woodlands may have a relatively greater effect on the establishment of pinyon than juniper.
The pinyon jay (Gymnorhinus cyanocephalus) and other members of the seed caching corvids play an important role in pinyon pine regeneration. These birds cache the seeds in the soil for future use. Those seeds that escape harvesting by the birds and rodents have the opportunity to germinate under favorable soil and climatic conditions (Lanner 1981). A mutualistic relationship exists between the trees that produce food and the animals that disperse the seeds, thereby insuring perpetuation of the trees. Large crops of seeds may stimulate reproduction in birds, especially the pinyon jay (Ligon 1974).
Initial response of native understory species following fire correlates closely with percent crown cover. In general, research indicates that understory response to disturbance is most productive when crown cover is at or below 20%. Beyond 30%, there is a rapid decline in understory species and soil seed reserves (Huber et al. 1999). The reference state understory vegetation of black sagebrush, bluebunch wheatgrass and Indian ricegrass further supports the evidence of a presettlement community with an open overstory and infrequent ground fire.
Black sagebrush plants have no morphological adaptations for surviving fire and must reestablish from seed following fire (Wright et al. 1979). The ability of black sagebrush to establish after fire is mostly dependent on the amount of seed deposited in the seed bank the year before the fire. Seeds typically do not persist in the soil for more than 1 growing season (Beetle 1960). A few seeds may remain viable in soil for 2 years (Meyer 2008); however, even in dry storage, black sagebrush seed viability has been found to drop rapidly over time, from 81% to 1% viability after 2 and 10 years of storage, respectively (Stevens et al. 1981). Thus, repeated frequent fires can eliminate black sagebrush from a site. Black sagebrush in zones receiving 12 to 16 inches of annual precipitation, however, have been found to have greater fire survival (Boltz 1994). In lower precipitation zones, rabbitbrush may become the dominant shrub species following fire, often with an understory of Sandberg bluegrass and/or cheatgrass and other weedy species.
The effect of fire on bunchgrasses relates to culm density, culm-leaf morphology, and the size of the plant. The initial condition of bunchgrasses within the site along with seasonality and intensity of the fire factor into the individual species’ responses. For most forbs and grasses, the growing points are located at or below the soil surface, providing relative protection from disturbances which decrease above ground biomass, such as grazing or fire. Thus, fire mortality is more correlated to duration and intensity of heat (Wright 1971, Young 1983). Season and severity of the fire will also influence plant response, which will vary depending on post-fire soil moisture availability.
Fire will remove aboveground biomass from bluebunch wheatgrass but plant mortality is generally low (Robberecht and Defossé 1995) because the buds are underground (Conrad and Poulton 1966) or protected by foliage. Uresk et al. (1976) reported burning increased vegetative and reproductive vigor of bluebunch wheatgrass. Thus, bluebunch wheatgrass is considered to experience slight damage to fire but is more susceptible in drought years (Young 1983). Plant response will vary depending on season, fire severity, fire intensity and post-fire soil moisture availability.
Indian ricegrass is fairly fire tolerant (Wright 1985), which is likely due to its low culm density and below ground plant crowns. Vallentine (1989) cites several studies in the sagebrush zone that classified Indian ricegrass as being slightly damaged from late summer burning. Indian ricegrass has also been found to reestablish on burned sites through seed dispersed from adjacent unburned areas (Young 1983, West 1994). Thus the presence of surviving, seed producing plants facilitates the reestablishment of Indian ricegrass. Grazing management following fire to promote seed production and establishment of seedlings is important.
Sandberg bluegrass, a minor component of this ecological site, has been found to increase following fire likely due to its low stature and productivity (Daubenmire 1975). Sandberg bluegrass may retard reestablishment of deeper rooted bunchgrass.State and transition model
Custom diagramStandard diagram
Figure 5. State and Transition Model
Figure 6. Legend
More interactive model formats are also available. View Interactive Models
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 1
Reference StateThe Reference State 1.0 is representative of the natural range of variability under pristine conditions. This Reference State has four general community phases: an old-growth woodland phase, a shrub-herbaceous phase, an immature woodland phase, and an infilled tree phase. State dynamics are maintained by interactions between climatic patterns and disturbance regimes. 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. Plant community phase changes are primarily driven by fire, periodic drought, and/or insect or disease attack.
Community 1.1
Community PhaseThis phase is characterized by widely dispersed old-growth pinyon and juniper trees with a black sagebrush perennial bunchgrass understory. The visual aspect is dominated by singleleaf pinyon and Utah juniper which make up 15 to 30 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. Black sagebrush is the primary understory shrub. Forbs such as goldenweed, phlox, and buckwheat are minor components. Overall, the understory is sparse with production ranging between 250 to 500 pounds per acre. Fires within this community are infrequent and likely 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.
Forest overstory.OLD GROWTH FORESTLAND: The visual aspect and vegetal structure are dominated by pinyon and juniper that have reached maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns of singleleaf pinyon and Utah juniper are typically either irregularly or smoothly flat-topped or rounded. Tree canopy cover ranges from 15 to 30 percent. Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. Few tree seedlings and/or saplings occur in the understory. Infrequent, yet periodic, wildfire is a natural disturbance influencing the understory of mature pinyon-juniper forestlands. This stage of community development is assumed to be representative of this forestland site in the pristine environment.
Forest understory. Understory vegetative composition is about 35 percent grasses, 15 percent forbs and 50 percent shrubs and young trees when the average overstory canopy is medium (15 to 30 percent). Average understory production ranges from 250 to 500 pounds per acre with a medium canopy cover. Understory production includes the total annual production of all species within 4½ feet of the ground surface.<br /> <br /> Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. Few tree seedlings and/or saplings occur in the understory. Infrequent, yet periodic, wildfire is a natural disturbance influencing the understory of mature pinyon-juniper woodlands. This stage of community development is assumed to be representative of this woodland site in the pristine environment.
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 112 135 225 Grass/Grasslike 88 105 175 Tree 25 30 50 Forb 25 30 50 Total 250 300 500 Community 1.2
Community PhaseThis 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 and saplings up to 4.5 feet in height may be present. Black sagebrush may be present in unburned patches. Burned tree skeletons may be present; however these have little or no effect on the understory vegetation.
Forest overstory.Various amounts of tree seedlings and saplings (up to 4.5 in height) may be present up to the point where they are obviously a major component of the vegetal structure. Tree cover is less than 10 percent.
Forest understory. Herbaceous vegetation and sprouting shrubs dominate the site. Understory production ranges from 600 to 1000 pounds per acre. Vegetation consist of grasses, forbs, shrubs in association with tree seedlings and saplings.
Community 1.3
Community PhaseThis community phase is characterized by an immature woodland, with pinyon and juniper trees averaging over 4.5 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.
Forest overstory.IMMATURE WOODLAND: The visual aspect and vegetal structure are dominated by Utah juniper and singleleaf pinyon trees greater than 4.5 feet in height. The upper crown of dominant and co-dominant trees are cone or pyramidal shaped. Seedlings and saplings of pinyon and Utah juniper are present in the understory. Dominants are the tallest trees on the site; co-dominants are 65 to 85 percent of the highest of dominant trees.
Forest understory. Understory vegetation is moderately influenced by a tree overstory canopy of about 10 to 20 percent. Understory production ranges from 300 to 700 lbs/ac.
Community 1.4
Community Phase (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 black 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 tree state 3.0. This community phase is typically described as early Phase II woodland (Miller et al. 2008).
Forest overstory.MATURE FOREST: The visual aspect and vegetal structure are dominated by pinyon and juniper that have reached maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns of singleleaf pinyon and Utah juniper are typically either irregularly or smoothly flat-topped or rounded. Tree canopy cover ranges from 20 to 35 percent.
Forest understory. Understory vegetation is a mix of shrubs, grasses, forbs and pinyon and juniper seedlings and saplings. Production ranges from 75 to 250 pounds per acre. Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. Few tree seedlings and/or saplings occur in the understory. Infrequent, yet periodic, wildfire is a natural disturbance influencing the understory of mature pinyon-juniper woodlands.
Pathway a
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 for the perennial bunchgrasses to increase on the site.
Pathway b
Community 1.1 to 1.4Time without disturbance such as fire, drought, or disease will allow for the gradual return of singleleaf pinyon and Utah juniper and understory species.
Pathway a
Community 1.2 to 1.3Time without disturbance such as fire, drought, or disease will allow for the gradual maturation of the singleleaf pinyon and Utah Juniper component. Black sagebrush and other understory species eventually reestablish.
Pathway b
Community 1.3 to 1.2Fire reduces or eliminates tree canopy, allowing perennial grasses to increase on the site.
Pathway a
Community 1.3 to 1.4Time without disturbance such as fire, drought, or disease will allow for the gradual maturation of singleleaf pinyon and Utah juniper. Infilling by younger trees continues.
Pathway a
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%. Over time young trees mature to replace and maintain the old-growth woodland. The understory increases in density and vigor.
Pathway b
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 StateThis state is similar to the Reference State 1.0, with four general community phases: an old-growth woodland phase, a shrub-herbaceous phase, an immature tree phase, and an infilled woodland 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 non-natives’ 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.
Community 2.1
Community PhaseThis phase is characterized by a widely dispersed old-growth pinyon and juniper trees with a black sagebrush perennial bunchgrass understory. The visual aspect is dominated by singleleaf pinyon and Utah juniper which make up 15 to 30 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. Black sagebrush is the primary understory shrub. Forbs such as goldenweed, phlox, and buckwheat are minor components. Overall, the understory is sparse with production ranging between 250 to 500 pounds per acre. Annual non-native species are present in trace amounts.
Forest overstory.OLD GROWTH FORESTLAND: The visual aspect and vegetal structure are dominated by pinyon and juniper that have reached maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns of singleleaf pinyon and Utah juniper are typically either irregularly or smoothly flat-topped or rounded. Tree canopy cover ranges from 15 to 30 percent.
Forest understory. Understory vegetative composition is about 35 percent grasses, 15 percent forbs and 50 percent shrubs and young trees when the average overstory canopy is medium (15 to 30 percent). Average understory production ranges from 250 to 500 pounds per acre with a medium canopy cover. Understory production includes the total annual production of all species within 4½ feet of the ground surface.<br /> <br /> Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. Few tree seedlings and/or saplings occur in the understory. Infrequent, yet periodic, wildfire is a natural disturbance influencing the understory of mature pinyon-juniper woodlands. This stage of community development is assumed to be representative of this woodland site in the pristine environment.
Community 2.2
Community Phase
Figure 8. T.Stringham July 2013, NV779 MU3435, Lithic Calcixerepts
Figure 9. P Novak-Echenique, NV779 MU 3435, Lithic Calcixere
This 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 4.5 feet in height may be present. Black 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.
Forest overstory.Various amounts of tree seedlings (less than 4.5 feet in height) may be present up to the point where they are obviously a major component of the vegetal structure. Tree canopy cover is less than 10 percent.
Forest understory. Herbaceous vegetation and woody shrubs dominate the site. Understory production ranges from 600 to 1000 pounds per acre.
Community 2.3
Community PhaseThis community phase is characterized by an immature woodland, with pinyon juniper trees averaging over 4.5 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 non-native species are present.
Forest overstory.IMMATURE FORESTLAND: The visual aspect and vegetal structure are dominated by Utah juniper and singleleaf pinyon trees greater than 4.5 feet in height. The upper crown of dominant and co-dominant trees are cone or pyramidal shaped. Seedlings and saplings of pinyon and Utah juniper are present in the understory. Dominants are the tallest trees on the site; co-dominants are 65 to 85 percent of the highest of dominant trees.
Forest understory. Understory vegetation is moderately influenced by a tree overstory canopy of about 10 to 20 percent. Understory production ranges from 300 to 700 lbs/ac.
Community 2.4
Community Phase (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 black 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 3.0. This community phase is typically described as early Phase II woodland (Miller et al. 2008).
Forest overstory.MATURE FOREST: The visual aspect and vegetal structure are dominated by pinyon and juniper that have reached maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns of singleleaf pinyon and Utah juniper are typically either irregularly or smoothly flat-topped or rounded. Tree canopy cover ranges from 20 to 35 percent.
Forest understory. Understory vegetation is a mix of shrubs, grasses, forbs and pinyon and juniper seedlings and saplings. Production ranges from 75 to 250 pounds per acre. Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. Few tree seedlings and/or saplings occur in the understory. Infrequent, yet periodic, wildfire is a natural disturbance influencing the understory of mature pinyon-juniper woodlands.
Pathway a
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 increase on the site.
Pathway b
Community 2.1 to 2.4Time without disturbance such as fire, drought, or disease will allow for the gradual infilling of singleleaf pinyon and Utah juniper and associated understory.
Pathway a
Community 2.2 to 2.3Time without disturbance such as fire, drought, or disease will allow for the gradual maturation of the singleleaf pinyon and Utah juniper component. Black sagebrush may eventually reestablish. Excessive herbivory may reduce perennial grass understory.
Pathway b
Community 2.3 to 2.2Fire reduces or eliminates tree canopy, allowing perennial grasses and sprouting shrubs to dominate the site.
Pathway a
Community 2.3 to 2.4Time without disturbance such as fire, drought, or disease will allow for the gradual maturation of singleleaf pinyon and Utah juniper. Infilling by younger trees continues.
Pathway a
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 black sagebrush and perennial bunchgrass community increases in density and vigor. Annual non-natives present in trace amounts.
Pathway b
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 StateThis state is identifiable by 30 to 50+ percent cover of Utah juniper and singleleaf pinyon. Trees are at maximal height and upper crowns may be flat-topped or rounded. Understory vegetation is sparse due to increasing shade and competition from trees. Leader growth on tree saplings. Understory production is typically less than 300 lbs/ac.
Community 3.1
Community Phase
Figure 10. T.Stringham July 2013, NV779, MU 3435
Singleleaf pinyon and Utah juniper dominate the aspect. Understory vegetation is thinning. Perennial bunchgrasses are sparse and black 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. Soil redistribution is common. This community phase is typically described as a Phase II woodland (Miller et al. 2008). Tree recruitment is still active.
Forest overstory.In the absence of wildfire or other naturally occurring disturbances, the tree canopy on this site can become very dense. This stage is dominated by singleleaf pinyon and Utah juniper that have reached maximal heights for the site. Dominant and co-dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns are typically irregularly flat-topped or rounded.
Forest understory. Understory is sparse and production is less than 250 pounds per acre.
Community 3.2
Community PhaseSingleleaf pinyon and Utah juniper dominate the aspect and influence ecological processes on the site. 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. Shrubs no longer dominate the understory. Black sagebrush skeletons are common or the sagebrush has been dead long enough that only scattered limbs remain. Mat-forming forbs or Sandberg’s bluegrass may dominate interspaces. Annual non-native 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). Tree recruitment is limited. Trees are the dominant vegetation and are controlling ecological site processes on the site.
Forest overstory.In the absence of wildfire or other naturally occurring disturbances, the tree canopy on this site can become very dense. This stage is dominated by singleleaf pinyon and Utah juniper that have reached maximal heights for the site. Dominant and co-dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns are typically irregularly flat-topped or rounded.
Forest understory. Understory vegetation is sparse and production is less than 100 pounds per acre.
Pathway a
Community 3.1 to 3.2Time without disturbance such as fire, drought, or disease will allow for the gradual maturation of singleleaf pinyon and Utah juniper. Infilling by younger trees continues.
State 4
Annual StateThis community is characterized by the dominance of annual non-native species such as cheatgrass and mustards. Rabbitbrush may dominate the overstory.
Community 4.1
Community Phase
Figure 11. T.Stringham July 2013, NV779 MU 3435
Cheatgrass, mustards and other non-native annual species dominate the site. Sandberg’s bluegrass and other perennial bunchgrasses may be present in trace amounts. Tree skeletons may dominate aspect for a number of years. Rabbitbrush may be present.
State 5
Eroded StateAbiotic factors including soil redistribution and erosion, excessive soil temperature, soil crusting and sealing are primary drivers of ecological condition within this state. Soil moisture, soil nutrients and soil organic matter distribution and cycling are severely altered due to degraded soil surface conditions.
Utah juniper dominates the overstory and herbaceous species may be present in trace amount particularly under tree canopies. Regeneration of trees or herbaceous species is not evident.
Community 5.1
Community PhaseSoil erosion is driving site dynamics. Singleleaf pinyon and Utah juniper and other species may still be present on the site, but are reduced in density and not controlling site processes. Recruitment of trees or herbaceous species is limited. Site function is controlled by soil erosion, wind and extreme soil temperatures.
Forest overstory.The visual aspect and vegetal structure are dominated by pinyon and juniper that have reached maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns of singleleaf pinyon and Utah juniper are typically either irregularly or smoothly flat-topped or rounded. Tree canopy cover ranges from 20 to 35 percent.
Forest understory. Understory vegetation is sparse and production is less than 100 pounds per acre.
Transition A
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 B
State 1 to 3Trigger: Time and a lack of disturbance allow trees to dominate site resources; may be coupled with inappropriate herbivory that favors shrub and tree dominance. Slow variables: Over time the abundance and size of trees will increase. Threshold: Pinyon and juniper canopy cover is greater than 30 percent. Little understory vegetation remains due to competition with trees for site resources.
Transition A
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: Singleleaf pinyon and Utah juniper canopy cover is greater than 30%. Little understory vegetation remains due to competition with trees for site resources.
Transition B
State 2 to 4Trigger: Canopy fire reduces the pinyon and juniper overstory and facilitates the annual non-native species in the understory to dominate the site. Slow variables: Over time, cover, production and seed bank of annual non-native species increases. Threshold: Loss of deep-rooted perennial bunchgrasses and shrubs changes temporal and spatial nutrient capture and cycling within the community. Increased canopy cover of trees allows severe stand-replacing fire. The increased seed bank of non-native, annual species responds positively to post-fire conditions facilitating the transition to an Annual State.
Restoration pathway A
State 3 to 2Manual or mechanical thinning of trees coupled with range seeding. Probability of success is highest from community phase 3.1.
Conservation practices
Brush Management Range Planting Transition A
State 3 to 4Trigger: Canopy fire reduces the pinyon and juniper overstory and facilitates the annual non-native species in the understory to dominate the site. Slow variables: Over time, cover, production and seed bank of annual non-native species increases. Threshold: Loss of deep-rooted perennial bunchgrasses and shrubs changes temporal and spatial nutrient capture and cycling within the community. Increased canopy cover of trees allows severe stand-replacing fire. The increased seed bank of non-native, annual species responds positively to post-fire conditions facilitating the transition to an Annual State.
Transition B
State 3 to 5Trigger: Time allows for an increase in tree canopy cover and greatly reduces cover of all understory species. Bare ground greatly increases, allowing for soil movement. Slow variables: Increasing water and wind erosion coupled with lack of cover changes site soil properties: temperature, infiltration rates, and levels of organic matter no longer support reference vegetation. Threshold: Soil redistribution and erosion is significant and linked to vegetation mortality evidenced by pedestalling and burying of herbaceous species and / or lack of recruitment in the interspaces.
Transition A
State 4 to 5Trigger: Catastrophic fire or multiple fires. Slow variables: Bare ground interspaces become large and connected; water flow paths long and continuous; understory sparse. Threshold: Soil redistribution and erosion is significant and linked to vegetation mortality evidenced by pedestalling and burying of herbaceous species and / or lack of recruitment in the interspaces.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Primary Perennial Grasses 105–243 Indian ricegrass ACHY Achnatherum hymenoides 30–72 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 30–72 – muttongrass POFE Poa fendleriana 15–36 – Sandberg bluegrass POSE Poa secunda 15–36 – squirreltail ELEL5 Elymus elymoides 15–27 – 2 Secondary Perennial Grasses 5–25 Ross' sedge CARO5 Carex rossii 0–5 – needle and thread HECO26 Hesperostipa comata 1–2 – basin wildrye LECI4 Leymus cinereus 1–2 – blue grama BOGR2 Bouteloua gracilis 1–2 – Forb3 Perennial Forbs 4–17 buckwheat ERIOG Eriogonum 3–10 – western stoneseed LIRU4 Lithospermum ruderale 0–10 – phlox PHLOX Phlox 1–2 – thistle CIRSI Cirsium 0–2 – Shrub/Vine4 Primary Shrubs 78–168 black sagebrush ARNO4 Artemisia nova 30–72 – curl-leaf mountain mahogany CELE3 Cercocarpus ledifolius 15–27 – wild crab apple PERA4 Peraphyllum ramosissimum 15–27 – Stansbury cliffrose PUST Purshia stansburiana 15–27 – snowberry SYMPH Symphoricarpos 3–15 – 5 Secondary Shrubs 1–2 Utah serviceberry AMUT Amelanchier utahensis 1–2 – Tree6 Evergreen 6–30 Utah juniper JUOS Juniperus osteosperma 3–15 – singleleaf pinyon PIMO Pinus monophylla 3–15 – 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 – 50-70 – 0 singleleaf pinyon PIMO Pinus monophylla Native – 30-50 – 0 Table 8. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 1.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 1.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 12. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 13. Community 2.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 14. Community 2.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 15. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 16. Community 3.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 17. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 18. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Livestock Interpretations:
The history of livestock grazing in the pinyon-juniper ecosystem goes back to more than 200 years, depending on the particular locality within the ecosystem (Hurst 1975). Historically, pinyon-juniper woodlands were much more open and supported a diverse understory that provided forage for both livestock and wildlife. Historic livestock overuse and increased stand densities have reduced the carrying capacity of these pinyon-juniper stands and many current stands only provide shade and shelter for livestock.
Black sagebrush palatability has been rated as moderate to high depending on the ungulate and the season of use (Horton 1989, Wambolt 1996). The palatability of black sagebrush increase the potential negative impacts on remaining black sagebrush plants from grazing or browsing pressure following fire (Wambolt 1996). Pronghorn utilize black sagebrush heavily (Beale and Smith 1970). On the Desert Experiment Range, black sagebrush was found to comprise 68% of pronghorn diet even though it was only the 3rd most common plant. Fawns were found to prefer black sagebrush utilizing it more than all other forage species combined (Beale and Smith 1970). Domestic livestock will also utilize black sagebrush. The domestic sheep industry that emerged in the Great Basin in the early 1900s was largely based on wintering domestic sheep in black sagebrush communities (Mozingo 1987). Domestic sheep will browse black sagebrush during all seasons of the year depending on the availability of other forage species with greater amounts being consumed in fall and winter. Black sagebrush is generally less palatable to cattle than to domestic sheep and wild ungulates (McArthur et al. 1982); however, cattle use of black sagebrush has also been shown to be greatest in fall and winter (Schultz and McAdoo 2002), with only trace amounts being consumed in summer (Van Vuren 1984).
Inappropriate grazing management during the growing season will cause a decline in understory plants such as bluebunch wheatgrass and Indian ricegrass. Bluebunch wheatgrass is moderately grazing tolerant and is very sensitive to defoliation during the active growth period (Blaisdell and Pechanec 1949, Laycock 1967, Anderson and Scherzinger 1975, Britton et al. 1990). Herbage and flower stalk production was reduced with clipping at all times during the growing season; however, clipping was most harmful during the boot stage (Blaisdell and Pechanec 1949). Tiller production and growth of bluebunch was greatly reduced when clipping was coupled with drought (Busso and Richards 1995). Mueggler (1975) estimated that low vigor bluebunch wheatgrass may need up to 8 years rest to recover. Although an important forage species, it is not always the preferred species by livestock and wildlife.
Indian ricegrass is a preferred forage species for livestock and wildlife (Cook 1962, Booth et al. 2006). This species is often heavily utilized in winter because it cures well (Booth et al. 2006). It is also readily utilized in early spring, being a source of green feed before most other perennial grasses have produced new growth (Quinones 1981). Booth et al. (2006) note that the plant does well when utilized in winter and spring. Cook and Child (1971) however, found that repeated heavy grazing reduced crown cover, which may reduce seed production, density, and basal area of these plants. Additionally, heavy early spring grazing reduces plant vigor and stand density (Stubbendieck 1985). In eastern Idaho, productivity of Indian ricegrass was at least 10 times greater in undisturbed plots than in heavily grazed ones (Pearson 1965). Cook and Child (1971) found significant reduction in plant cover after seven years of rest from heavy (90%) and moderate (60%) spring use. The seed crop may be reduced where grazing is heavy (Bich et al. 1995). Tolerance to grazing increases after May, thus spring deferment may be necessary for stand enhancement (Pearson 1964, Cook and Child 1971); however, utilization of less than 60% is recommended.
Reduced bunchgrass vigor or density provides an opportunity for Sandberg bluegrass, muttongrass, mat forming forbs and/or cheatgrass and other invasive species to occupy interspaces. Sandberg bluegrass increases under grazing pressure (Tisdale and Hironaka 1981) and is capable of co-existing with cheatgrass. Field surveys indicate native, mat-forming forbs may also increase with decreased bunchgrass density.
Wildlife Interpretations:
Pinyon-juniper woodlands provide a diversity of habitat for wildlife. Although the foliage of pinyon and juniper varies in palatability among fauna, the pinyon nuts and juniper berries are preferred by many species. The understory species provide fruits and browse for large ungulates, small mammals, birds and beaver (Wildlife Action Plan Team 2012).
Ungulates will use pinyon and juniper trees for cover and graze the foliage. The understory species also provide critical browse for deer. The trees provide important cover for mule deer (Odocoileus heminous), elk (Cervus canadensis) wild horses, mountain lion (Puma concolor), bobcat (Lynx rufus) and pronghorn (Antilocapra americana) (Gottfried and Severson 1994, Coates and Schemnitz 1994, Logan and Irwin 1985, Evans 1988).
Mule deer is considered the dominant big game species in the pinyon-juniper woodland and depend heavily on these woodlands for cover, shelter, and emergency forage during severe winters (Frischknecht 1975). Mule deer will eat singleleaf pinyon and juniper foliage, using the foliage moderately in winter, spring, and summer (Kufeld et al. 1973). Deep snows in higher elevation forest zones force mule deer and elk down into pinyon-juniper habitats during winter. This change in habitat allows mule deer and elk to browse the dwarf trees and shrubs (Gottfried and Severson 1994).
The diet of pronghorn antelope varies considerably; however, singleleaf pinyon was shown to comprise 1 to 2 percent of winter diet of pronghorn antelope that occur in pinyon-juniper habitat. Desert bighorn sheep (Ovis nelson) may utilize pinyon-juniper habitat, but only where the terrain is rocky and steep (Gottfried et al. 2000). Gray foxes, bobcats (Lynx rufus), coyotes (Canis latrans), weasels (Mustela frenata), skunks (Mephitis spp.), badgers (Taxidea taxus), and ringtail cats (Bassariscus astutus) search for prey in pinyon-juniper habitat woodlands (Short and McCulloch 1977).
Juniper "berries" or berry-cones are eaten by black-tailed jackrabbits, Lepus californicus, and coyotes (Gese et al. 1988, Kitchen et al. 2000). A study by Kitchen et al (1999) conducted in juniper-pinion habitat found vegetation in coyote scats was mainly grass seeds or juniper berries. Jackrabbits are a major dispenser of juniper seeds (Schupp et al. 1999). The pinyon mouse (Peromyscus truei) is a pinyon-juniper obligate and uses the woodlands for cover and food (Hoffmeister 1981). Other small mammals include the porcupine (Hystricomorph hystricidae), desert cottontail (Sylvilagus audubonii), Nuttall’s cottontail (S. nuttallii), deer mouse (Peromyscus maniculatus), Great Basin pocket mouse (Perognathus parvus), chisel-toothed kangaroo rat (Dipodomys microps) and desert woodrat (Neotoma lepida) (Turkowski and Watkins 1976).
Many bird species are associated with the pinyon-juniper habitat; some are permanent residents, some summer residents, and some winter residents, depending upon location. For birds and bats, the woodland provides structure for nesting and roosting, and locations for foraging. Singleleaf pinyon provides a number of cavities and the stringy, fibrous bark provides quality nesting material as well as the food provided by the tree’s seeds and berries (Short and McCulloch 1977). Many bird species depend on juniper berry-cones and pine nuts for fall and winter food (Balda and Masters 1980). Several bird species are obligates including (gray flycatcher (Epidonax wrightii) scrub jay (Aphelocoma californica), plain titmouse (Parus inornatus ridgwayi), and gray vireo (Vireo vicinior) and several species are semi-obligates including black-chinned hummingbird (Archilochus alexandri), ash-throated flycatcher (Myiarchus cinerascens), pinion jay (Gymnorhinus cyanocephalus), American bushtit (Psaltriparus minimus), Bewick’s wren (Thryomanes bewickii), Northern mockingbird (Mimus polyglottos), blue-gray gnatcatcher (Polioptila caerulea), black-throated gray warbler (Dendroica nigrescens), house finch (Haemorhous mexicanus), spotted towhee (Pipilo maculatus), lark sparrow (Chondestes grammacus) and black-chinned sparrow (Zonotrichia atricapilla) (Balda and Masters 1980). Ferruginous hawk (Buteo regalis), a conservation priority species due to recent population declines in Nevada, nest in older trees of sufficient size and structure to support their large nest platforms. (Holechek 1981).
Diurnal reptiles include the sagebrush swift (Sceloporus graciosus), the blue-bellied lizard (Sceloporus elongates) the western collard lizard, the Great Basin rattlesnake, the Great Basin gopher snake (Pituophis catenifer) and horned lizard, also occur in Utah juniper habitat (Frischknecht 1975). However, the distribution of most of herpetofauna present in pinyon-juniper woodlands is poorly understood and more research and management are needed.
Hydrological functions
Permeability is slow to moderately rapid. Runoff is medium to very high. Hydrologic soil groups are B, C, and D. Hydrologic processes are influenced by species composition, structural development and density patterns of the tree overstories and the nature of precipitation events occurring. Interception of precipitation is related to the composition, distribution, and density of trees in the overstory and intensity, duration, and type of precipitation. Infiltration rates are typically greater beneath tree overstories than on sites supporting herbaceous plants because the trees reduce the raindrop impact. The litter accumulation beneath the trees also slows overland flows. Evapotranspiration is generally the largest route of water outflow from the site ((Ffolliott and Gottfried 2012).
Recreational uses
The trees on this site provide a welcome break in an otherwise open landscape. It has potential for hiking, cross-country skiing, camping, and deer and upland game hunting.
Wood products
Pinyon wood is rather soft, brittle, heavy with pitch, and yellowish brown in color. Singleleaf pinyon has played an important role as a source of fuelwood and mine props. It has been a source of wood for charcoal used in ore smelting. It still has a promising potential for charcoal production. Other important uses for this tree are for Christmas trees and as a source of nuts for wildlife and human food. These trees have provided Indians with food for centuries. Thousands of pounds of nuts are gathered each year and sold on commercial markets throughout the United States.
PRODUCTIVE CAPACITY
This forestland community is of moderately low site quality for tree production. Site index ranges from 35 to 55 (Howell, 1940).
Productivity Class: 0.2 to 0.4
CMAI*: 2.7 to 5.2 ft3/ac/yr;
0.19 to 0.36 m3/ha/yr.
Culmination is estimated to be at 90 years.
*CMAI: is the culmination of mean annual increment or highest average growth rate of the stand in the units specified.
Fuelwood Production: 7 to 10 cords per acre for stands averaging 5 inches in diameter at 1 foot height with a medium canopy cover. There are about 289,000 gross British Thermal Units (BTUs) heat content per cubic foot of pinyon pine wood and about 274,000 gross BTUs heat content per cubic foot of Utah juniper. Solid wood volume in a cord varies but usually ranges from 65 to 90 cubic feet. Assuming an average of 75 cubic feet of solid wood per cord, there are about 21 million BTUs of heat value in a cord of mixed pinyon pine and Utah juniper.
Posts (7 foot): About 25 to 50 posts per acre in stands of medium canopy.
Christmas trees: 15 trees per acre per year in stands of medium canopy. Twenty-five trees per acre in stands of sapling stage.
Pinyon nuts: Production varies year to year, but mature woodland stage can yield 150 to 300 pounds per acre in favorable years.
MANAGEMENT GUIDES AND INTERPRETATIONS
1. LIMITATIONS AND CONSIDERATIONS
a. Potential for sheet and rill erosion is moderate to severe depending on slope.
b. Moderate to severe equipment limitations on steeper slopes and moderate to severe equipment limitations on sites having extreme surface stoniness.
c. Proper spacing is the key to a well managed, multiple use and multi-product pinyon-juniper woodland.
2. ESSENTIAL REQUIREMENTS
a. Adequately protect from wildfire.
b. Protect soils from accelerated erosion.
c. Apply proper grazing management.
3. SILVICULTURAL PRACTICES
a. Harvest cut selectively or in small patches size dependent upon site conditions) to enhance forage production.
1) Thinning and improvement cutting - Removal of poorly formed, diseased and low vigor trees for fuelwood.
2) Harvest cutting - Selectively harvest surplus trees to achieve desired spacing. Save large, healthy, full-crowned singleleaf pinyon trees for nut producers. Do not select only "high grade" trees during harvest.
3) Slash Disposal - broadcasting slash improves reestablishment of native understory herbaceous species and establishment of seeded grasses and forbs after tree harvest.
4) Spacing Guide - D+12
b. Prescription burning program to maintain desired canopy cover and manage site reproduction.
c. Mechanical tree removal (i.e. chaining) is usually not recommended on this site due to steep slopes.
d. Pest control - Porcupines can cause extensive damage and populations should be controlled.
e. Fire hazard - Fire usually not a problem in well-managed, mature stands.Other products
Utah juniper wood is very durable. Its primary uses have been for posts and fuelwood. It probably has considerable potential in the charcoal industry and in wood fiber products. The berries have been used by Indians for food. Pinyon-juniper ecosystems have had subsistence, cultural, spiritual, economic, aesthetic and medicinal value to Native American peoples for centuries, and singleleaf pinyon has provided food, fuel, medicine and shelter to Native Americans for thousands of years. The pitch of singleleaf pinyon was used as adhesive, caulking material, and a paint binder. It may also be used medicinally and chewed like gum. Pinyon seeds are a valuable food source for humans, and a valuable commercial crop. Indian ricegrass was traditionally eaten by some Native Americans. The Paiutes used seed as a reserve food source.
Other information
Black sagebrush is an excellent species to establish on sites where management objectives include restoration or improvement of domestic sheep, pronghorn, or mule deer winter range.
Table 19. 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 singleleaf pinyon PIMO 35 55 3 5 90 200 N/A Howell, Joseph Jr. 1940. Pinon [sic] and juniper, a preliminary study of volume, growth and yield. USDA, Soil Conservation Service. Region 8 Regional Bulletin 71, Forest Series 12. Utah juniper JUOS 35 55 3 5 – – – Supporting information
Type locality
Location 1: White Pine County, NV Township/Range/Section T12N R69E S12 Latitude 38° 55′ 37″ Longitude 114° 10′ 40″ General legal description About ¾ mile north of Snake Creek, Snake Range, Great Basin National Park, White Pine County, Nevada. Also occurs in Lincoln County, Nevada. 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.
Airola, D. A. 1980. Northeast Interior Zone: Vol. III - Birds & Vol. IV - Mammals. U.S. Gov. Printing Off.: 1980-690-082/26.
Beetle, A. A. 1960. A study of sagebrush. The section Tridentatae of Artemisia. Bull. Wyo. agric. Exp. Stn. 368:83 pp.
Bich, B. S., J. L. Butler, and C. A. Schmidt. 1995. Effects of Differential Livestock Use on Key Plant Species and Rodent Populations within Selected Oryzopsis hymenoides/Hilaria jamesii Communities of Glen Canyon National Recreation Area. The Southwestern Naturalist 40:281-287.
Blaisdell, J. P. and J. F. Pechanec. 1949. Effects of Herbage Removal at Various Dates on Vigor of Bluebunch Wheatgrass and Arrowleaf Balsamroot. Ecology 30:298-305.
Boltz, M. 1994. Factors influencing postfire sagebrush regeneration in south-central Idaho. Pages 281-290 in Proceedings -- ecology and mangement of annual rangelands. Gen. Tech. Rep. INT-GTR-313. U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Boise, ID.
Booth, D. T., C. G. Howard, and C. E. Mowry. 2006. 'Nezpar' Indian ricegrass: description, justification for release, and recommendations for use. Rangelands Archives 2:53-54.
Bradley, A. F., N. V. Noste, and W. C. Fischer. 1992. Gen. Tech. Rep. INT-287: Fire ecology of forests and woodlands in Utah. U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Ogden, UT.
Britton, C. M., G. R. McPherson, and F. A. Sneva. 1990. Effects of burning and clipping on five bunchgrasses in eastern Oregon. Great Basin Naturalist 50:115-120.
Bunting, S. 1994. Effects of Fire on Juniper woodland ecosystems in the great basin.in Proceedings--Ecology and Management of Annual Rangelands. USDA: FS Intermountain Research Station.
Busso, C. A. and J. H. Richards. 1995. Drought and clipping effects on tiller demography andgrowth of two tussock grasses in Utah. Journal of Arid Environments 29:239-251.
Caudle, D., J. DiBenedetto, M. Karl, H. Sanchez, and C. Talbot. 2013. Interagency ecological site handbook for rangelands. Available at: http://jornada.nmsu.edu/sites/jornada.nmsu.edu/files/InteragencyEcolSiteHandbook.pdf. Accessed 4 October 2013.
Chambers, J. C., B. A. Bradley, C. S. Brown, C. D’Antonio, M. J. Germino, J. B. Grace, S. P. Hardegree, R. F. Miller, and D. A. Pyke. 2013. Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America. Ecosystems:1-16.
Chambers, J.C., E.W. Schupp and S.B. Vander Wall. 1999. Seed dispersal and seedling establishment of pinyon and juniper species within the pinon-juniper woodland. IN: Proceedings: ecology and management of pinyon–juniper communities within the Interior West. Ogden, UT, USA: US Department of Agriculture, Forest Service, Rocky Mountain Research Station, RMRS-P-9:29-34.
Christopherson, J. 2014. Dwarf Mistletoe (Arceuthobium spp.). Nevada Division of Forestry, 2478 Fairview Drive, Carson City Nevada.
Conrad, C. E. and C. E. Poulton. 1966. Effect of a wildfire on Idaho fescue and bluebunch wheatgrass. Journal of Range Management:138-141.
Cook, C. W. 1962. An Evaluation of Some Common Factors Affecting Utilization of Desert Range Species. Journal of Range Management 15:333-338.
Cook, C. W. and R. D. Child. 1971. Recovery of Desert Plants in Various States of Vigor. Journal of Range Management 24:339-343.
Daubenmire, R. 1970. Steppe vegetation of Washington. 131 pp.
Daubenmire, R. 1975. Plant succession on abandoned fields, and fire influences in a steppe area in southeastern Washington. Northwest Science 49:36-48.
Durham, G. 2014. Juniper Pocket Rot (Pyrofomes demidoffii.). Nevada Division of Forestry, 2478 Fairview Drive, Carson City, Nevada 89701.
Eyre, F.H. (editor). 1980. Forest Cover Types of the United States and Canada. Society of American Foresters, Washington, D.C.
Ffolliott, P.F. and G.J. Gottfried. 2012. Hydrologic processes in the pinyon-juniper woodlands: A literature review. Gen. Tech. Rep. RMRS-GTR-271. Fort Collins, CO. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 20 p.
Fire Effects Information System (Online; http://www.fs.fed.us/database/feis/plants/).
Gruell, G.E. 1999. Historical and modern roles of fire in pinyon-juniper. In:Proceedings: ecology and management of pinyon–juniper communities within the Interior West. Ogden, UT, USA: US Department of Agriculture, Forest Service, Rocky Mountain Research Station, RMRS-P-9:35-46.
Heyerdahl, E.K., Miller, R.F, and Parsons, R.A. 2006. History of fire and Douglas-fir establishment in a savanna and sagebrush grassland mosaic, southwestern Montana, USA. Forest Ecology and Management. 230:107-118.
Holmes, R.L., R.K., Adams, H.C. Fritts. 1986. Tree ring chronologies of western North America: California, eastern Oregon and northern Great Basin. Chronology Series VI. Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ 183p.
Horton, H. 1989. Interagency forage and conservation planting guide for Utah. Extension circular 433. Utah State University, Utah Cooperative Extension Service, Logan UT.
Howell, J. 1940. Pinyon and juniper: a preliminary study of volume, growth, and yield. Regional Bulletin 71. Albuquerque, NM: USDA, NRCS; 90p.
Houghton, J.G., C.M. Sakamoto, and R.O. Gifford. 1975. Nevada’s Weather and Climate, Special Publication 2. Nevada Bureau of Mines and Geology, Mackay School of Mines, University of Nevada, Reno, NV.
Huber, A., S. Goodrich, K. Anderson. 1999. Diversity with successional status in the pinyon-juniper/mountain mahogany/bluebunch wheatgrass community type Near Dutch John, Utah. US Department of Agriculture, Forest Service, Rocky Mountain Research Station Proceedings RMRSP-9.
Kitchen, S. G. and E. D. McArthur. 2007. Big and black sagebrush landscapes. Pages 73-95 in Fire ecology and mangement of the major ecosystems of southern Utah. Gen. Teck. Rep. RMRMS-GTR-202. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, CO.
Koniak, S. 1985. Succession in pinyon-juniper woodlands following wildfire in the Great Basin. The Great Basin Naturalist 45:556-566.
Laycock, W. A. 1967. How heavy grazing and protection affect sagebrush-grass ranges. Journal of Range Management:206-213.
McArthur, E. D., A. Blaner, A. P. Plummer, and R. Stevens. 1982. Characteristics and hybridization of important Intermountain shrubs: 3. Sunflower family. En Ref. in Forest. Abstr 43:2176.
Meewig, R.O. and R.L. Bassett. 1983. Pinyon-juniper. In:Silvicultural Systems for the Major Forest Types of the United States. Agric. Handbook. 455, Washington, D.C.: USDA:84-86.
Meyer, S. E. 2008. Artemisia L. -- sagebrush. Pages 274-280 in F. T. Bonner and R. P. Karrfalt, editors. The woody plant seed manual. Agriculture Handbook 727. U.S. Department of Agriculture, Forest Service, Washington, DC.
Miller, R.F. and T.J. Rose. 1995. Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon. Great Basin Naturalist. 55:37-45.
Miller, R.F. and T.J. Rose. 1999. Fire history and western juniper encroachment in sagebrush steppe. Journal of Range Management.52:550-559.
Miller, R.F. R.J. Tausch and W. Waichler. 1999. Old-growth juniper and pinyon woodlands. In: Monsen, S.D. and R. Stevens. Comps. Proceedings: Ecology and Management of Pinyon-Juniper communities within the interior West; 1997 September 15-18; Provo, UT. USDA, Forest Service RMRS-P-9: 375-384 Logan Ut.
Miller, R.F. and R.J. Tausch. 2001. The role of fire in pinyon and juniper woodlands: a descriptive analysis. In: Galley, K.E.M., Wilson, T.P. eds. Invasive Species: the role of fire in the control and spread of invasive species symposium. Miscellaneous Publication No. 11, Tall Timbers Research Station, Tallahassee, FL. 15-30.
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 Inter-Mountain West. USDA Forest Service RMRS-RP-69. pp. 1-13.
Mozingo, H. N. 1987. Shrubs of the Great Basin: A natural history. University of Nevada Press, Reno NV.
Mueggler, W. F. 1975. Rate and Pattern of Vigor Recovery in Idaho Fescue and Bluebunch Wheatgrass. Journal of Range Management 28:198-204.
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Pearson, L. 1964. Effect of harvest date on recovery of range grasses and shrubs. Agronomy Journal 56:80-82.
Pearson, L. C. 1965. Primary Production in Grazed and Ungrazed Desert Communities of Eastern Idaho. Ecology 46:278-285.
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Contributors
DBP/GKB
T Stringham
P NovakEcheniqueRangeland 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 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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