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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
MLRA notes
Major Land Resource Area (MLRA): 022A–Sierra Nevada and Tehachapi Mountains
This ESD was developed using older policy requirements which have been improved with the intent of improving ESD products overall. Users should approach these materials with some caution as the content herein, while likely useful for some purposes, was developed within parameters now recognized as needing varying levels of improvement. As always, a site-specific investigation is highly recommended when site-specific management alternatives are to be developed and/or management decisions are to be made.
Each ESD is an interpretation of the ecological relationships between biotic and abiotic aspects of the landscape. Users of this document should be aware of the limitations of this tool to the extent that specific local conditions may not be entirely captured within the ESD. In particular, management decisions should be supported by site-specific inventories, assessments and planning processes based on the best available information including and extending beyond the ESD.
An ESD is not a permanent determination of ecological dynamics. Rather, each ESD is an evolving body of work intrinsically tied to the soil surveys and data associated with soil map unit components of correlated soil-ecological site relationships. As new information becomes available, updates may be made or may be underway at any given time. Minor updates may be made without announcement when such changes do not modify the ecological site concept, the soils correlated or the state-and-transition model.
Table 1. Dominant plant species
Tree (1) Pinus contorta
(2) Tsuga mertensianaShrub Not specified
Herbaceous (1) Carex
Physiographic features
This site occurs on mountain sideslopes. Aspects are typically southeast and southwest and occasionally northwest facing slopes. Elevations range from 9000 to 11,000 feet. Slopes are between 4 and 50 percent.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 9000 – 11000 ft Slope 4 – 50 % Aspect SE, SW Climatic features
The climate is characterized as subhumid-continental with cold, moist winters and cool, dry summers. Average annual precipitation is 20 to over 40 inches. Mean annual air temperature is 36 to 43 degrees F. The average growing season is 30 to 70 days. Climate data used to support this section were derived from PRISM and is not specifically tied to any dominant climate station.
Table 3 Representative climatic features
Frost-free period (average) 0 days Freeze-free period (average) 0 days Precipitation total (average) 0 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
There are no influencing water features associated with this site.
Soil features
The soils associated with this site are shallow and somewhat excessively drained. They are formed in colluvium and residuum from granodiorite. They are skeletal, with over 40 percent rock fragments in the control section. Runoff is medium to very high, and permeability is rapid. Available water holding capacity is very low. The soils are usually moist in the moisture control section during late fall, winter and spring, and dry from mid July through early October. The moisture regime is typic xeric and temperature regime is cryic. The soils associated with this site are classified as Typic Cryorthents.
CA693 Tahoe Basin Area, California and Nevada
9421;Jobsis-Whittell-Rock outcrop complex, cool, 8 to 30 percent slopes;Typic Cryorthents
9461;Whittell-Jobsis-Rock outcrop complex, cool, 30 to 75 percent slopes;Typic Cryorthents
CA729 Toiyabe National Forest Area, California
110;Jobsis-Whittell-Rock outcrop complex, 8 to 30 percent slopes;Typic Cryorthents
111;Whittell-Jobsis-Rock outcrop complex, 30 to 75 percent slopes;Typic Cryorthents
112;Jobsis-Whittell-Rock outcrop complex, cool, 8 to 30 percent slopes;Typic Cryorthents
113;Whittell-Jobsis-Rock outcrop complex, cool, 30 to 75 percent slopes;Typic Cryorthents
CA790 Yosemite National Park, California
111t;Whittell-Jobsis-Rock outcrop complex, 30 to 75 percent slopes, mountains, cryic;Typic Cryorthents
NV773 Douglas County Area, Nevada
112;Jobsis-Whittell-Rock outcrop complex, cool, 8 to 30 percent slopes;Typic Cryorthents
113;Whittell-Jobsis-Rock outcrop complex, cool, 30 to 75 percent slopes;Typic Cryorthents
Table 4. Representative soil features
Surface texture (1) Extremely bouldery loamy coarse sand
(2) Very gravelly loamy coarse sand
Family particle size (1) Sandy
Drainage class Somewhat excessively drained Permeability class Rapid Soil depth 10 – 20 in Surface fragment cover <=3" 25 – 0 % Surface fragment cover >3" 20 – 0 % Available water capacity
(0-40in)0.6 – 0 in Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)4.5 – 5.5 Subsurface fragment volume <=3"
(Depth not specified)16 – 40 % Subsurface fragment volume >3"
(Depth not specified)2 – 26 % Ecological dynamics
Major Successional Stages of Forest
Development
HERBACEOUS: Vegetation is dominated by grasses and forbs under full sunlight. This stage is experienced for a short period after major disturbance such as crown fire or tree harvest. 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.
SHRUB-HERBACEOUS: Herbaceous vegetation and woody shrubs dominate the site. This stage is experienced within two to three years after fire or harvest. 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.
SAPLING: In 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. Understory shrubs dominate the plant community.
IMMATURE FOREST: The visual aspect and vegetal structure are dominated by lodgepole pine and mountain hemlock greater than 4.5 feet in height. At this stage of forest development, the tree canopy has successfully broken through the suppression of early successional shrub communities. The young pines are still very susceptible to fire at this stage. The upper crown of dominant and co-dominant lodgepole pine and mountain hemlock are cone or pyramidal shaped. Seedlings and saplings of pines are common in the understory. Dominants are the tallest trees on the site; co-dominants are 65 to 85 percent of the highest of dominant trees. Understory vegetation is moderately influenced by a tree overstory canopy of about 10 to 20 percent.
MATURE FOREST: The visual aspect and vegetal structure are dominated by lodgepole pine and mountain hemlock that have reached or are near maximal heights for the site. Tree canopy cover ranges from 15 to 20 percent. This stage of community development is assumed to be representative of this forest site in the pristine environment.
OVER-MATURE FOREST: This stage is dominated by lodgepole pine and mountain hemlock that have reached maximal heights for the site. Understory vegetation is sparse due to tree competition, overstory shading, duff accumulation, etc. Tree canopy cover is commonly greater than 45 percent.
This site is dominate by lodgepole pine with mountain hemlock. Sierra lodgepole pine grows in areas with cold, wet winters and dry,
warm summers. Sierra lodgepole pine establishes soon after disturbance and is
moderately shade tolerant. It forms stable climax communities in the zone just above red fir and white fir-mountain hemlock forests
Fire Ecology:
Fire-return intervals in Sierra lodgepole pine forests vary. On the eastern slope where
drier conditions prevail, such fires may occur at intervals of less than 20 years. Sierra lodgepole pine is usually killed by fire because of its shallow root system and thin bark. Stand-replacing fires are related to insect attacks, particulary by pine mountain beetle, and declining vigor and high fuel loading in older stands. When fires occur in Sierra lodgepole stands, they are usually intense and extensive.
Mountain hemlock is easily killed by fire. Mountain hemlock is generally slow to regenerate after fire and fire injury makes mountain hemlock very susceptible to insects and disease.
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 characterized by an overstory canopy of 10 to 20 percent. The sites is dominated by lodgepole pine and mountain hemlock with whitebark pine being a minor component. Sedges are the most common understory grass. Aster, buckwheat, and phlox are common understory forbs.
Overstory tree canopy composition is 50 percent lodgepole pine 50 percent mountain hemlock with a possible 5 or less percent being whitebark pine.Forest overstory.MATURE WOODLAND: The visual aspect and vegetal structure are dominated by lodgepole pine and mountain hemlock that have reached or are near maximal heights for the site. Tree canopy cover ranges from 15 to 25 percent. This stage of community development is assumed to be representative of this woodland site in the pristine environment.<br /> <br />
Forest understory. Understory vegetative composition (air-dry weight) is about 35 percent grasses, 30 percent forbs and 35 percent shrubs and young trees when the average overstory canopy is medium (15 to 20 percent). Average understory production ranges from 150 to 450 pounds per acre with a medium canopy cover. Understory production includes the total annual production of all species within 41/2 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)Grass/Grasslike 53 88 158 Shrub/Vine 45 75 135 Forb 45 75 135 Tree 7 12 22 Total 150 250 450 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/Grasslikes 51–106 Ross' sedge CARO5 Carex rossii 25–60 – bluegrass POA Poa 13–23 – threadleaf sedge CAFI Carex filifolia 13–23 – Forb2 Perennial Forbs 15–65 rockcress ARABI2 Arabis 3–13 – lousewort PEDIC Pedicularis 3–13 – mule-ears WYAM Wyethia amplexicaulis 3–13 – Shrub/Vine3 Primary Shrubs 13–23 currant RIBES Ribes 13–24 – Tree4 Trees 15–39 whitebark pine PIAL Pinus albicaulis 3–13 – lodgepole pine PICO Pinus contorta 3–13 – mountain hemlock TSME Tsuga mertensiana 3–13 – Interpretations
Animal community
Lodgepole pine and Mountain hemlock stands provide good hiding and thermal cover for many
wildlife species. Mountain hemlock habitat types provide summer range for mule
deer, grouse and bear. Blue grouse feed on Sierra lodgepole pine needles during the winter.
Hydrological functions
The hydrology of this site is characterized by heavy snowmelt in the spring, with very little precipitation in the summer months.
Recreational uses
This area can be used for hiking biking, cross country skiing and camping.
Wood products
The wood is moderately strong and light colored and is most often used for
small-demension lumber and pulp. The wood is also used for railway ties, mine timbers, interior finish, crates, kitchen cabinets, and
flooring and ceilings.
Low quality site for tree production.
Site index for lodgepole pine ranges from about 45 to 61. (Table 25, SCS, 190-V-NFM Amend.3; from Dahms, 1964. USDA PNW Research paper No. 8.) Site index for mountain hemlock ranges from about 40 to 46. (Figure 3, USDA FS 1990, from Burns and Honkala).
Productivity Class :(Lodgepole Pine) 3
CMAI*: <36 to 50 cu ft/ac/yr;
<2.5 to 3.5 cu m/ha/yr.
*CMAI: is the culmination of mean annual increment highest average growth rate of the stand in the units specified.
Productivity Class :(Mountain Hemlock) 3
Basal Area (Lodgepole Pine): 60 sq. ft./acre with average D.B.H=8.7" and average age 58 years (AB69).
Basal Area (Mountain hemlock): 60 sq. ft./acre with average D.B.H=6.7" and average age 68 years (AB69).
Basal Area (Whitebark pine): 60 sq. ft./acre with average D.B.H=8.0" and average age 53?? years (AB69).
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. Do not select only "high grade" trees for harvest.
3) Slash disposal - broadcasting slash improves reestablishment of native understory species and establishment of seeded grasses and forbs after tree harvest.
b. Prescription burning program to maintain desired canopy cover and manage site reproduction.
c. Mechanical tree removal on suitable sites to enhance forage production and manage site reproduction.
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
Native Americans chewed the resin, wove baskets from the bark, concocted
a poultice for dressing wounds from the pitch, and collected the cambium in the spring for food.
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 lodgepole pine PICO 35 60 36 50 – – – Supporting information
Type locality
Location 1: Mono County, CA Township/Range/Section T10N R19E S11 Latitude 38° 43′ 35″ Longitude 119° 51′ 42″ General legal description Toiyabe National Forest.Toiyabe National Forest, near the head waters of Buck Creek. Other references
Fire Effects Information System[Online], http://www.fs.fed.us/database/feis
Plants Database [Online], http://www.plants.usda.gov
Lanner, Ronald M.. 1984. Trees of the Great Basin, A Natural History. Reno University of Nevada Press.
Dahms, W..G. 1964. Data From Grass And Net Yield Table For Lodgepole Pine. USDA PNW Res. Paper No. 8.
Barnes, G.H., 1962 Yield of even –aged stands of western hemlock. USDA FS Tech. Bull. No. 1273.
USDA-NRCS. 1980. National Forestry Manual - Part 537. Washington, D.C.
Potter, D. A. 1998. Forested Communities of the Upper Montane in the Central and Southern Sierra Nevada. USDA FA PSW GTR 169.
Contributors
ALM/GKB
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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