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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Associated sites
F029XY086NV Rocky Loamy Slope 16+
Table 1. Dominant plant species
Tree (1) Pinus monophylla
Shrub (1) Amelanchier utahensis
(2) Quercus turbinellaHerbaceous (1) Poa fendleriana
Physiographic features
This site occurs on mountain sideslopes of mostly northerly aspects at the lower elevations of its range and on all aspects at higher elevations. Slopes range from 30 to 75 percent. Elevations are 6200 to about 7300 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 6200 – 7300 ft Slope 30 – 75 % Aspect Aspect is not a significant factor Climatic features
The climate of this area is largely influenced by topographical barriers. The Sierra Nevada mountains drain much of the moisture of the storms moving from the Pacific. The Rocky Mountains divert cold air masses from the Great Basin. The local topography of the mountain peaks also influence the climate of this area. This area also lies in the path of the warm, moist air masses from the Gulf of Mexico. Consequently eastern Nevada can expect an average of 20 to 25 thunderstorm days per year, mostly during July through September. Approximately 25 percent of the precipitation occurs from July through September. The climate is considered cool continental with warm, moist summers and cold, wet winters. Average annual precipitation is 14 to 18 inches. Mean annual air temperature is 46 to 52 degrees F. The average frost-free period is 90 to 120 days. The nearest climate station is Caliente, Nevada.
Table 3 Representative climatic features
Frost-free period (average) 120 days Freeze-free period (average) 0 days Precipitation total (average) 20 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Influencing water features are not associated with this site.
Soil features
Soils are typically deep and well drained. They are derived from residuum and colluvium from volcanic tuff. These soils are skeletal with 35 to over 50 percent gravels, cobbles or stones, by volume, distributed throughout their profile. There are very high amounts of vitric volcanic ash and glass throughout the soil profile which enhances the water holding capacity of these soils. Available water capacity is moderate. There are high amounts of rock fragments at the soil surface. Runoff is high and potential for sheet and rill erosion is moderate to severe depending on slope. The soils have a mollic epipedon and a cambic horizon. Soil temperature regime is mesic and soil moisture regime is ustic. The soil associated with this site is Laross, ashy-skeletal, glassy, mesic Vitrandic Haplustolls.
Table 4. Representative soil features
Surface texture (1) Cobbly loam
(2) Gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 40 – 60 in Surface fragment cover <=3" 10 – 20 % Surface fragment cover >3" 5 – 20 % Available water capacity
(0-40in)5.9 – 6 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)7 – 7.2 Subsurface fragment volume <=3"
(Depth not specified)15 – 45 % Subsurface fragment volume >3"
(Depth not specified)5 – 40 % Ecological dynamics
The plant communities of this ecological site are dynamic in response to changes in disturbance regimes and weather patterns. Pinyon forests are generally a climax vegetation type throughout its range, reaching climax about 300 years after disturbance, with an ongoing trend toward increased tree density and canopy cover and a decline in understory species over time. 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 forests and adjacent shrublands and grasslands provide favorable microhabitats for singleleaf pinyon seedling establishment. These areas are active zones for seed dispersal, nurse plants are available, and pinyon seedlings are only affected by competition from grass and other herbaceous vegetation for a couple of years.
Several natural and anthropogenic processes can lead to changes in the spatial distribution of pinyon forests over time. These include 1) tree seedling establishment during favorable climatic periods, 2) tree mortality (especially seedlings and saplings) during periods of drought, 3) expansion of trees into shrublands in response to overgrazing and/or fire suppression, and 4) removal of trees by humans, fire, or other disturbance episodes. Specific successional pathways after disturbance are dependent on a number of variables such as plant species present at the time of disturbance and their individual responses to disturbances, 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.
Fire Ecology:
On high-productivity sites where sufficient fine fuels existed, pinyon communities burn every 100 years or longer. Thin bark and lack of self pruning make singleleaf pinyon very susceptible to intense fire. Mature singleleaf pinyon can survive low-severity surface fires but is killed by more severe fires. Most tree seedlings are killed by fire, but cached seeds may survive. Aboveground parts of Utah serviceberry may be killed or consumed under fire conditions with sufficient flame lengths. Utah serviceberry may be slightly harmed by fire, depending on moisture conditions, but is generally considered to be fire tolerant. Utah serviceberry sprouts from the root crown following fire. Soil moisture is important to aid sprouting. Mountain big sagebrush is highly susceptible to injury from fire. It is often top-killed by fire and will not resprout. Muttongrass is unharmed to slightly harmed by light-severity fall fires. Muttongrass appears to be harmed by and slow to recover from severe fire. Indian ricegrass can be killed by fire, depending on severity and season of burn. Indian ricegrass reestablishes on burned sites through seed dispersed from adjacent unburned areas. Prairie junegrass is reported as showing little or no damage to moderate damage from fire. The small stature of prairie Junegrass and coarse textured foliage aid in protection of these meristematic tissue areas. Possessing coarsely textured foliage and a small clump size also limits the potential for fire damage.State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Reference StateThe reference state is representative of the natural range of variability under pristine conditions. The overstory canopy is dominated by pinyon pine. Primary natural disturbances affecting this ecological site are wildfire, disease, insect attack and periodic drought. Timing of fire combined with weather events determines plant community dynamics. Increased mortality following drought is likely caused by a combination of insect attack and disease.
Community 1.1
Reference Plant Community - Mature ForestThe visual aspect and vegetal structure are dominated by singleleaf pinyon that have reached or are near maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump. Upper crowns are typically either irregularly or smoothly flat-topped or rounded. Overstory tree canopy composition ranges from 95 to 100 percent singleleaf pinyon with less than 5 percent Utah juniper. Tree canopy cover ranges from 20 to 30 percent. Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. Infrequent, yet periodic, wildfire is presumed to be a natural factor influencing the understory of mature pinyon forests. This stage of community development is assumed to be representative of this forest site in the pristine environment.
Utah serviceberry and mountain big sagebrush are the principal understory shrubs. Muttongrass is the most prevalent understory grass. Understory vegetative composition is about 35 percent grasses, 5 percent forbs, and 60 percent shrubs and young trees when the average overstory canopy is medium (20 to 30 percent). Average understory production ranges from 600 to 1300 pounds per acre with a medium canopy cover.Forest overstory.The overstory canopy is generally 100 percent pinyon pine. Dominant trees average greater than five inches in diameter at one-foot stump and have reached the maximal heights for the site. Upper crowns are typically either irregularly or smoothly flat-topped or rounded. Tree canopy cover ranges from 20 to 30 percent.
Forest understory. Understory vegetative composition is about 35 percent grasses, 5 percent forbs and 60 percent shrubs and young trees when the average overstory canopy is medium (20 to 30 percent). Average understory production ranges from 600 to 1300 pounds per acre with a medium canopy cover. Understory production includes the total annual production of all species within 4.5 feet of the ground surface.
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)Shrub/Vine 351 513 735 Grass/Grasslike 210 315 455 Forb 30 45 65 Tree 9 27 45 Total 600 900 1300 Community 1.2
HerbaceousVegetation is dominated by grasses and forbs under full sunlight. This stage is experienced after a major disturbance such as crown fire. Skeleton forest (dead trees) remaining after fire or residual trees left following harvest have little or no affect on the composition and production of the herbaceous vegetation.
Community 1.3
Shrub-HerbaceousHerbaceous vegetation and woody shrubs dominate the site. This stage of development is experienced within five to ten years following fire (Bock and Bock 1990) or harvest and may persist for several years. Several shrub species in the understory are adapted to recover and recolonize quickly following wildfire. With abnormally frequent wildfire the understory vegetation reflects a chaparral community. Many chaparral communities can be retarded from progressing toward ecological higher stages by an unnaturally, short fire cycle. Various amounts of tree seedlings (less than 20 inches in height) may be present up to the point where they are obviously a major component of the vegetal structure.
Community 1.4
SaplingIn the absence of disturbance, the tree seedlings develop into saplings (20 inches to 4.5 feet in height) with a range in canopy cover of about 5 to 10 percent. Vegetation consists of grasses, forbs and shrubs in association with tree saplings.
Community 1.5
Immature ForestThe visual aspect and vegetal structure are dominated by pinyon trees greater than 4.5 feet in height. The upper crown of singleleaf pinyon are cone or pyramidal shaped. Seedlings and saplings of pinyon are present in the understory. Dominants are the tallest trees on the site. Understory vegetation is moderately influenced by a tree overstory canopy of about 10 to 20 percent.
Community 1.6
Over-mature ForestIn the absence of wildfire or other naturally occurring disturbances, the tree canopy on this site can become very dense. At this stage singleleaf pinyon has 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. Understory vegetation is sparse or absent due to tree competition, overstory shading, duff accumulation, etc. Tree canopy cover is commonly greater than 50 percent.
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 180–378 muttongrass POFE Poa fendleriana 90–216 – Indian ricegrass ACHY Achnatherum hymenoides 45–81 – prairie Junegrass KOMA Koeleria macrantha 45–81 – 2 Secondary Perennial Grasses 20–50 desert needlegrass ACSP12 Achnatherum speciosum 5–10 – blue grama BOGR2 Bouteloua gracilis 5–10 – needle and thread HECO26 Hesperostipa comata 5–10 – Sandberg bluegrass POSE Poa secunda 5–10 – Forb3 Perennial 9–45 lupine LUPIN Lupinus 3–15 – hoary tansyaster MACA2 Machaeranthera canescens 3–15 – phlox PHLOX Phlox 3–15 – Shrub/Vine4 Primary Shrubs 135–297 Utah serviceberry AMUT Amelanchier utahensis 90–216 – mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 90–216 – 5 Secondary Shrubs 216–438 ashy silktassel GAFL2 Garrya flavescens 45–81 – Gambel oak QUGA Quercus gambelii 45–81 – Sonoran scrub oak QUTU2 Quercus turbinella 45–81 – currant RIBES Ribes 9–45 – greenleaf manzanita ARPA6 Arctostaphylos patula 9–45 – Mojave ceanothus CEGRV Ceanothus greggii var. vestitus 9–45 – Martin's ceanothus CEMA2 Ceanothus martinii 9–45 – alderleaf mountain mahogany CEMO2 Cercocarpus montanus 9–45 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 4–9 – Tree6 Evergreen 9–45 singleleaf pinyon PIMO Pinus monophylla 9–45 – Table 7. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 1.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 1.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 1.5 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 1.6 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Livestock Interpretations:
This site is suited to cattle and sheep grazing where terrain permits. Many areas are not used because of steep slopes or lack of adequate water. Grazing management should be keyed to perennial grass and palatable shrub production. Muttongrass is highly nutritious and remains palatable throughout the grazing season. Needlegrasses and Indian ricegrass provide palatable, nutritious feed during the late spring and early summer. New plants of all these grasses are established entirely from seed and grazing practices should allow for ample seed production and seedling establishment.
Stocking rates vary with such factors as kind and class of grazing animal, season of use and fluctuations in climate. Actual use records for individual sites, a determination of the degree to which the sites have been grazed, and an evaluation of trend in site condition offer the most reliable basis for developing initial stocking rates.
Selection of initial stocking rates for given grazing units is a planning decision. This decision should be made ONLY after careful consideration of the total resources available, evaluation of alternatives for use and treatment, and establishment of objectives by the decisionmaker.
The forage value rating is not an ecological evaluation of the understory as is the range condition rating for rangeland. The forage value rating is a utilitarian rating of the existing understory plants for use by specific kinds of grazing animals.
Wildlife Interpretations:
This site has high value for mule deer during the summer, fall and winter. Pinyon trees provide shelter from winter storms. Sites where water is available offer good quail habitat and are visited seasonally by mourning dove. It is also used by various song birds, rodents, reptiles and associated predators natural to the area.Hydrological functions
Runoff is high and permeability is moderate.
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.
Productivity Class: 0.2 to 0.4
CMAI*: 3.7 to 5.9 ft3/ac/yr;
0.26 to 0.41 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: 4 to 7 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 20 to 40 posts per acre in stands of medium canopy.
Christmas trees: 10 trees per acre per year in stands of medium canopy. Ten trees per acre in stands of sapling stage.
Pinyon nuts: Production varies year to year, but mature woodland stage can yield 250 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 forestland.
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+11
b. Prescription burning program to maintain desired canopy cover and manage site reproduction.
c. Mechanical tree removal (i.e. chaining) is not recommended on this site.
d. Fire hazard - Fire usually not a problem in well-managed, mature stands.Other products
The pitch of singleleaf pinyon was used by Native Americans as an 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. Native Americans used big sagebrush leaves and branches for medicinal teas, and the leaves as a fumigant. Bark was woven into mats, bags and clothing. Utah serviceberry fruits were used by Native Americans and early European explorers in North America for food and medicine. Indian ricegrass was traditionally eaten by some Native Americans. The Paiutes used the seed as a reserve food source.
Other information
Utah serviceberry has been used to revegetate big game winter range and for surface stabilization. It grows slowly from seed and therefore transplanting may be more successful than seeding for revegetation projects. Prairie Junegrass can recolonize areas that have been subjected to severe water stress. Recolonization by prairie Junegrass provides protective cover to help subsequent post-drought, successional plant species growth.
Table 12. 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 45 65 4 6 92 200 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. singleleaf pinyon PIMO 20 30 4 6 92 202 N/A Chojnacky, David C. 1986. Pinyon-juniper site quality and volume growth equations for Nevada. USDA, Forest Service. Intermountain Research Station Research Paper INT-372. Supporting information
Other references
Bock, C.E., and J.H. Bock. 1990. Effects of fire on wildlife in southwestern lowland habitats. Pages 50–64 in J.S. Krammes (technical coordinator). Proceedings of the symposium on effects of fire management of southwestern natural resources. General Technical Report RM-191, U.S. Department of Agriculture, Forest Service, Fort Collins, CO.
Chojnacky, D.C., 1987. Volume and Growth Prediction for Pinyon-juniper; In "Proceedings: P/J Conference" (1986), Reno, NV. General Tech Report INT-215, Ogden, UT. USDA-USFS, Intermtn Res Sta, 1987. pp 207-215.
Howell, J., 1940. Pinyon and juniper: a preliminary study of volume, growth, and yield. Regional Bulletin 71. Albuquerque, NM: USDA, SCS; 90p.
USDA-NRCS. 1998. National Forestry Manual - Part 537. Washington, D.C.
Contributors
RWA
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 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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