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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) Pinus albicaulis
Shrub (1) Artemisia tridentata subsp. vaseyana
Herbaceous (1) Bromus marginatus
Physiographic features
This forestland community occurs on smooth to concave sideslopes of mountains. The site is typically found on northerly aspects at lower elevations and on all aspects at higher elevations. Slopes are generally 50 to 75 percent. Elevations are 6,000 to 9,000 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain
Elevation 6000 – 9000 ft Slope 50 – 75 % Aspect Aspect is not a significant factor Climatic features
The climate associated with this site is cold, continental, and is characterized by cold, moist winters and cool, dry summers. Average annual precipitation is at least 16 inches. Mean annual air temperature is 35 to 40 degrees F. The average frost-free period is 35 to 90 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) 60 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
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
Soils associated with this site are shallow and somewhat excessively drained. These soils are skeletal with 35 to over 50 percent rock fragments, by volume, distributed through the soil profile. Available water holding capacity is very low, but trees and shrubs extend their roots into the bedrock allowing them to utilize deep moisture. Runoff is very high and potential for sheet and rill erosion is very high. The soil series associated with this site include: Rodell.
Table 4. Representative soil features
Surface texture (1) Very bouldery coarse sandy loam
Family particle size (1) Loamy
Drainage class Somewhat excessively drained Permeability class Rapid Soil depth 10 – 20 in Surface fragment cover <=3" 51 – 55 % Surface fragment cover >3" 22 – 25 % Available water capacity
(0-40in)1 – 1.1 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)5.6 – 6.5 Subsurface fragment volume <=3"
(Depth not specified)30 – 34 % Subsurface fragment volume >3"
(Depth not specified)9 – 21 % Ecological dynamics
Fire Ecology:
Whitebark pine ecosystems have a mixed severity fire regime of widely ranging fire intensities and frequencies. Mean fire return intervals range from 30 to 350 years. Two strategies allow whitebark pine to survive in fire-prone ecosystems: survival of large and refugia trees, and postfire seedling establishment facilitated by Clark's nutcrackers. Mature trees usually survive low-, and sometimes moderate-severity surface fires. Bark thickness is moderate: thinner than ponderosa pine but thicker than lodgepole pine. Pole- and smaller-sized whitebark pine usually do not survive surface fires, but patchy fires resulting from fuel-limited whitebark pine habitats reduces whitebark pine mortality. Mountain big sagebrush is highly susceptible to injury from fire. It is often top-killed by fire and will not resprout. Mountain brome is likely to be top-killed by fire, although the coarse stems and broad leaves may be more fire-resistant than fine-leaved bunchgrasses. Mountain brome is most susceptible to fire damage when it is actively growing in spring and early summer. Columbia needlegrass is only slightly to moderately damaged by fire, because it has relatively few culms per clump which may help to minimize the amount of subsurface heat transfer and subsequent damage. Western needlegrass is moderately damaged by fire. The recovery time is between 3 and 5 years. 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. Nevada bluegrass is generally unharmed by fire. It produces little litter, and its small bunch size and sparse litter reduces the amount of heat transferred to perennating buds in the soil.
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 has 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 10 percent. Vegetation consists of grasses, forbs and shrubs in association with tree saplings.
IMMATURE FORESTLAND: Whitebark pine 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 whitebark pine plants are prevalent in the understory. Understory vegetation is moderately influenced by a tree overstory canopy of about 10 to 20 percent.
MATURE FORESTLAND: The visual aspect and vegetal structure are dominated by whitebark pine 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 forestlands. This stage of forestland development is assumed to be representative of this forestland site in a pristine environment.
OVER-MATURE FORESTLAND: This stage is dominated by whitebark pine that have reached maximal heights for the site. Dominant and codominant trees average greater than six inches in diameter at the 4½ foot height (DBH). Understory vegetation is sparse due to tree competition, overstory shading, duff accumulation, etc. Tree canopy cover is commonly greater than 40 percent.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 whitebark pine (Pinus albicaulis). Mountain big sagebrush, currant, mountain brome, Columbia and western needlegrasses, and Nevada bluegrass are the principal understory plants. Overstory tree canopy composition is 100 percent whitebark pine. An overstory canopy cover of about 20 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 whitebark pine 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 forestlands. This stage of forestland development is assumed to be representative of this forestland site in a pristine environment.
Forest understory. Understory vegetative composition is about 50 percent grasses, 5 percent forbs and 45 percent shrubs and young trees when the average overstory canopy is medium (21 to 25 percent). Average understory production ranges from 150 to 300 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 50 100 150 Shrub/Vine 37 74 111 Tree 8 16 24 Forb 5 10 15 Total 100 200 300 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 60–120 mountain brome BRMA4 Bromus marginatus 20–48 – prairie Junegrass KOMA Koeleria macrantha 10–18 – Dore's needlegrass ACNED Achnatherum nelsonii ssp. dorei 10–18 – western needlegrass ACOCO Achnatherum occidentale ssp. occidentale 10–18 – 2 Secondary Perennial Grasses 4–20 big squirreltail ELMU3 Elymus multisetus 2–10 – Forb3 Perennial 4–20 lupine LUPIN Lupinus 2–10 – beardtongue PENST Penstemon 2–10 – Shrub/Vine4 Primary Shrubs 20–48 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 20–48 – 5 Secondary Shrubs 2–10 currant RIBES Ribes 2–10 – Tree6 Evergreen 10–18 whitebark pine PIAL Pinus albicaulis 10–18 – Interpretations
Animal community
Livestock Interpretations:
This site is not suited to livestock grazing although livestock may concentrate on this site taking advantage of the shade and shelter offered by the tree overstory.
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 and fall. Whitebark pine trees provide protection from summer heat. Upland game species including blue grouse and ruffed grouse use this site. 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 rapid. Hydrologic soil group is D.
Recreational uses
The trees on this site provide a beautiful contrast to the adjacent quaking aspen communities. Steep slopes inhibit many forms of recreation. It has potential for hiking, camping, and deer and upland game hunting.
Wood products
PRODUCTIVE CAPACITY
Very low quality site for tree production. At present, site productivity and site index information is not available for whitebark pine.
Productivity Class: 0
CMAI*: <0.9 to 1.4 ft3/ac/yr;
<0.06 to 0.09 m3/ha/yr.
*CMAI: is the culmination of mean annual increment or highest average growth rate of the stand in the units specified.
MANAGEMENT GUIDES AND INTERPRETATIONS
1. LIMITATIONS AND CONSIDERATIONS
a. Moderate to severe equipment limitations due to surface stoniness.
b. Severe equipment limitations due to steep slopes.
c. Potential for sheet and rill erosion is severe.
2. ESSENTIAL REQUIREMENTS
a. Protect soils from accelerated erosion.
b. Adequately protect from uncontrolled fire.
3. SILVICULTURAL PRACTICES
Silvicultural treatments are not feasible on this site due to poor site quality and severe limitations for equipment and tree harvest.Supporting information
Type locality
Location 1: Humboldt County, NV Township/Range/Section T43N R28E S1 UTM zone N UTM northing 357278 UTM easting 4615823 Latitude 41° 40′ 53″ Longitude 118° 42′ 53″ General legal description SW 1/4 SW 1/4, About 1400 feet south of the west side of Blue Lake, Pine Forest Range, 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, NRCS; 90p.
USDA-NRCS Plants Database (Online; http://www.plants.usda.gov).
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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