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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Table 1. Dominant plant species
Tree (1) Juniperus osteosperma
Shrub (1) Artemisia arbuscula subsp. longicaulis
Herbaceous (1) Achnatherum thurberianum
(2) Achnatherum speciosumPhysiographic features
This forestland site occurs on mostly convex sideslopes of plateaus, hills, and mountains on all aspects. Slope gradients are generally from 15 to 50 percent. Elevations are from 4400 to about 6400 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
(2) Hill
Elevation 4400 – 6400 ft Slope 15 – 50 % Aspect Aspect is not a significant factor Climatic features
The climate associated with this site is semiarid and characterized by cool, moist winters and warm, dry summers. Average annual precipitation is about 8 to 12 inches. Mean annual air temperature is 47 to 50 degrees F. The average growing season is 90 to 120 days.
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).
Average annual precipitation is 16 to over 20 inches. Mean annual air temperature is 41 to 44 degrees F. The average growing season is about 50 to 70 days.
Mean annual precipitaion at the Bear Creek, Nevada SNOTEL station (170501020301) is 37.69 inches.
monthly mean precipitation is:
January 3.84; February 3.75; March 4.38; April 4.9;
May 3.99; June 2.82; July .95; August 1.66;
September 1.22; October 2.12;
November 3.67; December 4.38.Table 3 Representative climatic features
Frost-free period (average) 110 days Freeze-free period (average) 0 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
">Influencing water features
There are no influencing water features associated with this site.
Soil features
The soils associated with this site have formed in residuum from weathered shale rock sources. These soils are very shallow, with depth to bedrock ranging from 5 to 10 inches. Available water capacity is very low, but trees and shrubs extend their roots into fractures in the bedrock allowing them to utilize deep moisture. Runoff is very high and the potential for sheet and rill erosion is moderate to severe depending on slope. The soil series associated with this site include: Coppereid.
Table 4. Representative soil features
Surface texture (1) Gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 5 – 10 in Surface fragment cover <=3" 23 – 35 % Surface fragment cover >3" 0 – 3 % Available water capacity
(0-40in)1.2 – 1.3 in Calcium carbonate equivalent
(0-40in)5 – 15 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)7.9 – 9 Subsurface fragment volume <=3"
(Depth not specified)22 – 23 % Subsurface fragment volume >3"
(Depth not specified)2 – 3 % Ecological dynamics
Utah juniper is not shade tolerant. It is a climax species in harsh areas where stands are open and regeneration can occur without competition for light.
Across the West, junipers have expanded their historical range in the years since European settlement, Utah juniper is used by many birds and animals, both wildlife and livestock, for cover and food, especially into sagebrush-grass communities below areas of traditional pinyon-juniper. Overgrazing, fire suppression, and climatic change have been identified as potential causes of juniper invasion. In the absence of fire or other disturbances, trees eventually dominate the site and crowd out herbaceous and shrub species.
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.
Major Successional Stages of Forestland Development
HERBACEOUS: Vegetation is dominated by grasses and forbs under full sunlight. This stage is experienced after a major disturbance such as wildfire. Skeleton forest (dead trees) remaining after fire or other disturbances have little or no affect on the composition and production of the herbaceous vegetation.
SHRUB-HERBACEOUS: Herbaceous vegetation and woody shrubs dominate the site. Various amounts of tree seedlings (less than 20 inches in height) may be present up to the point where they are obviously a component of the vegetal structure.
SAPLING: In the absence of disturbance, the tree seedlings develop into saplings (20 inches to 4.5 feet in height) with a canopy cover generally less than 5 percent. Vegetation consists of grasses, forbs and shrubs in association with tree saplings.
IMMATURE FORESTLAND: Utah juniper greater than 4½ feet in height form a major constituent of the visual aspect and vegetal structure of the plant community. The upper crown of dominant and codominant trees are pyramidal-shaped. Young juniper plants are prevalent in the understory. Understory vegetation is minimally influenced by a tree overstory canopy of about 10 to 20 percent.
MATURE FORESTLAND: The visual aspect and vegetal structure are dominated by Utah juniper that have reached or are near maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Tree canopy cover is typically about 20 to 30 percent. Understory vegetation is strongly influenced by tree competition. Infrequent, yet periodic wildfire is a natural factor influencing the development and maintenance of these mature woodlands. This stage of forestland development is assumed to be representative of this woodland site in a pristine environment.
OVER-MATURE FORESTLAND: This stage is dominated by Utah juniper that have reached maximal heights for the site. Dominant and codominant trees average greater than five inches in diameter at one-foot stump height. Upper crowns of most trees are typically irregularly flat-topped or rounded. Understory vegetation is sparse due to tree competition, overstory shading, duff accumulation, etc. Tree canopy cover is commonly greater than 35 percent.
Fire Ecology:
The fire return intervals for Utah juniper communities range from 10 to 30 years. Utah juniper is usually killed by fire, especially when trees are small. Lahontan sagebrush is very susceptible to fire damage. Lahontan sagebrush is usually killed by fire and does not re-sprout. The recovery in burned areas is usually via small, light, wind-dispersed seed for all low sagebrush subspecies. Partially injured Lahontan sagebrush may re-grow from living branches, but sprouting does not occur. Thurber’s needlegrass is classified as moderately resistant, but depending on season of burn, phenology, and fire severity, this perennial bunchgrass is moderately to severely damaged by fire. Early season burning is more damaging to this needlegrass than late season burning. Desert needlegrass has persistent dead leaf bases, which make it susceptible to burning. Fire removes the accumulation; a rapid, cool fire will not burn deep into the root crown. Most perennial grasses have root crowns that can survive wildfire.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 Plant CommunityCommunity 1.1
Reference Plant CommunityThe reference plant community is dominated by Utah juniper. Lahontan sagebrush is the principal understory shrub. Nevada ephedra and spiny hopsage are other important shrubs of the understory community. Thurber's needlegrass, desert needlegrass, and Sandberg's bluegrass are the most prevalent understory grasses. Overstory tree canopy composition is 100 percent Utah juniper. An overstory canopy of 20 to 30 percent is assumed to be representative of tree dominance on this site in the pristine environment.
Forest overstory.MATURE FORESTLAND: The visual aspect and vegetal structure are dominated by Utah juniper that have reached or are near maximal heights for the site. Dominant trees average greater than five inches in diameter at one-foot stump height. Tree canopy cover is typically about 20 to 30 percent. Understory vegetation is strongly influenced by tree competition. Infrequent, yet periodic wildfire is a natural factor influencing the development and maintenance of these mature woodlands. This stage of forestland development is assumed to be representative of this woodland site in a pristine environment.
Forest understory. Understory vegetative composition is about 50 percent grasses, 10 percent forbs and 40 percent shrubs and young trees when the average overstory canopy is medium (20 to 30 percent). Average understory production ranges from 100 to 350 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.
Figure 5. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Grass/Grasslike 45 113 158 Shrub/Vine 40 100 140 Forb 10 25 35 Tree 5 12 17 Total 100 250 350 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 63–143 desert needlegrass ACSP12 Achnatherum speciosum 25–60 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 25–60 – Sandberg bluegrass POSE Poa secunda 13–23 – 2 Secondary Perennial Grasses 2–6 Indian ricegrass ACHY Achnatherum hymenoides 1–3 – squirreltail ELEL5 Elymus elymoides 1–3 – Forb3 Perennial 10–35 goldenweed PYRRO Pyrrocoma 3–13 – Shrub/Vine4 Primary Shrubs 25–60 little sagebrush ARARL3 Artemisia arbuscula ssp. longicaulis 25–60 – 5 Secondary Shrubs 11–45 curl-leaf mountain mahogany CELE3 Cercocarpus ledifolius 3–13 – Nevada jointfir EPNE Ephedra nevadensis 3–13 – spiny hopsage GRSP Grayia spinosa 3–13 – purple sage SADOI Salvia dorrii ssp. dorrii var. incana 1–3 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 1–3 – Tree6 Evergreen 3–13 Utah juniper JUOS Juniperus osteosperma 3–13 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to cattle and sheep grazing during the spring and fall. Grazing management should be keyed to Thurber needlegrass and desert needlegrass production. These grasses are highly nutritious. New plants are established entirely from seed and grazing practices should allow for ample seed production and seedling establishment. Livestock will often concentrate on this site taking advantage of the shade and shelter offered by the tree overstory. Many areas are not used because of steep slopes, surface stoniness or lack of adequate water. Attentive grazing management is required due to steep slopes and erosion hazards.
Harvesting trees under a sound management program for fuelwood or posts can open the tree canopy to allow increased production of understory plants desirable for grazing.
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 winter. Juniper trees provide protection from winter storms and juniper foliage is also browsed during the winter. The North American porcupine uses this site extensively. Areas where water is available offer good chukar 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. Feral horses will use this site in the late spring, summer and fall.Hydrological functions
Runoff is very high. Permeability is moderate. Hydrologic soil group is D.
Recreational uses
The trees on this site provide a welcome break in an otherwise open landscape. Steep slopes inhibit many forms of recreation. It has potential for hiking, camping, and deer and upland game hunting. Off-road vehicles can destroy the fragile soil-vegetation complex causing severe erosion problems.
Wood products
Utah juniper wood is very durable. Traditional products of Utah juniper are charcoal, fence posts, and fuelwood. It may have considerable potential in the charcoal industry and in wood fiber products.
PRODUCTIVE CAPACITY
Very low quality site for tree production. Site index ranges from about 12 to 18 (Howell,1940).
Productivity Class: 0
CMAI*: <0.7 to 1.1 ft3/ac/yr;
<0.05 to 0.08 m3/ha/yr.
(culmination is estimated to be at 100 years)
*CMAI: is the culmination of mean annual increment or highest average growth rate of the stand in the units specified.
Fuelwood Production: Less than 2 cords per acre for stands averaging 5 inches in diameter at 1-foot height with a medium canopy cover. There are about 274,000 gross British Thermal Units (BTUs) heat content per cubic foot of western juniper wood. Firewood is commonly measured by cord, or a stacked unit equivalent to 128 cubic feet. Solid wood volume in a cord varies, but 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 Utah juniper wood.
Posts (7 foot): 12 to 18 posts per acre in stands of medium canopy.
MANAGEMENT GUIDES AND INTERPRETATIONS
1. LIMITATIONS AND CONSIDERATIONS
a. Moderate to severe equipment limitations due to surface stoniness.
b. Moderate to severe equipment limitations on steeper slopes.
2. ESSENTIAL REQUIREMENTS
a. Protect soils from accelerated erosion.
b. Apply proper grazing management.
3. SILVICULTURAL PRACTICES
Silvicultural treatments are not feasible on this site due to poor site quality and severe limitations for equipment and tree harvest.Table 7. 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 Utah juniper JUOS 18 20 1 1 – – – Supporting information
Type locality
Location 1: Washoe County, NV Township/Range/Section T31N R22E S16 UTM zone N UTM northing 287072 UTM easting 4493695 Latitude 40° 33′ 60″ Longitude 119° 30′ 55″ General legal description Cottonwood Basin area, Fox Range, Washoe County, Nevada. This site also occurs in Humboldt County, Nevada. Other references
Fire Effects Information System (Online; http://www.fs.fed.us/database/feis/plants/).
Howell, J. 1940. Pinyon and Juniper: A Preliminary Study of Volume, Growth, and Yield. Regional Bulletin 71. Albuquerque, NM: USDA, SCS; 90p.
USDA-NRCS Plants Database (Online; http://www.plants.usda.gov).
Vasek, F.C. 1966. The Distribution and Taxonomy of Three Western Junipers; Brittonia 18:350-372.
USDA-NRCS. 1986. Field Identification of Western Nevada Junipers, Woodland Technical Note No. 15, Reno, Nevada. 8p.
Contributors
SW/CP
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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