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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) Tsuga mertensiana
Shrub Not specified
Herbaceous (1) Carex
(2) PoaPhysiographic features
This plant community typically occurs on upper mountain sideslopes and most often is found just below ridge tops on very steep north facing slopes. It characteristically lies above 7,500 feet. Winter snow packs persist into the summer season many years. Slopes are steep to very steep, ranging from 15-50 percent.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 7500 – 11000 ft Slope 15 – 50 % Aspect N Climatic features
">Influencing water features
Soil features
Table 3. Representative soil features
Surface texture (1) Very gravelly coarse sandy loam
(2) Very cobbly fine sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately rapid Soil depth 20 – 40 in Surface fragment cover <=3" 35 – 0 % Surface fragment cover >3" 5 – 0 % Available water capacity
(0-40in)2.4 – 0 in Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)4.5 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)19 – 41 % Subsurface fragment volume >3"
(Depth not specified)3 – 23 % Ecological dynamics
This site is dominated by mountain hemlock but western white pine and red fir may be important components of the overstory.
FIRE ECOLOGY OR ADAPTATIONS :
Mountain hemlock is not well adapted to fire. Fire. Fire resistance of
mountain hemlock has been rated as low. Its relatively thick bark
provides some protection, but low-hanging branches, highly flammable
foliage, and a tendency to grow in dense groups make it very susceptible
to fire injury.
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
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThis site is dominated by mountain hemlock, but western white pine and red fir mat be associated with the overstory community. Lodgepole pine occasionally occurs in the overstory. Understory is sparse and the shrub layer is essentially non existant. Ross' sedge and other sedges with slender and Bolander's bluegrass are the most prevalent understory grass and grass-like plants. Rockcress, phacelia, lousewort, and white flowered hawkweed are common understory forbs.
Forest overstory.Overstory tree canopy composition is about 70-85% mountain hemlock with up to 15% western white pine and 15% lodgepole pine and red fir.<br /> <br /> Major Successional Stages of Woodland Development<br /> 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.<br /> 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.<br /> 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.<br /> IMMATURE WOODLAND: The visual aspect and vegetal structure are dominated by mountain hemlock greater than 4.5 feet in height. At this stage of woodland 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 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.<br /> MATURE WOODLAND: The visual aspect and vegetal structure are dominated by mountain hemlock that have reached or are near maximal heights for the site. Tree canopy cover ranges from 40 to 50 percent. This stage of community development is assumed to be representative of this woodland site in the pristine environment.<br /> OVER-MATURE WOODLAND: This stage is dominated by 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 50 percent.<br /> <br /> PRODUCTIVE CAPACITY<br /> Very low quality site for tree production.<br /> Site index for mountain hemlock ranges from about 60 to 63. (Table 21, SCS, 190-V-NFM Amend.3; from Barnes, 1962. USDA FS Tech Bull 1273.)<br /> Productivity Class : 6<br /> CMAI*:<?? to ?? cu ft/ac/yr; <?? to ?? cu m/ha/yr.<br /> *CMAI: is the culmination of mean annual increment highest average growth rate of the stand in the units specified.<br /> Basal Area (Mountain Hemlock): 250 sq. ft./acre with average D.B.H=12" and average age 126 years (AB19).<br />
Forest understory. Understory vegetative composition (air-dry weight) is about 45 percent grasses and grass-like plants, 50 percent forbs and 5 percent young trees when the average overstory canopy is medium (26 to 35 percent). Average understory production ranges from 50 to 150 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 1. Annual production by plant type (representative values) or group (midpoint values)
Table 4. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Forb 25 50 75 Grass/Grasslike 23 35 38 Tree 3 5 8 Total 51 90 121 Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Grasslikes 10–30 Ross' sedge CARO5 Carex rossii 10–30 – 2 Cool Season Perennial Bunchgrasses 13–38 Sandberg bluegrass POSE Poa secunda 15–30 – Bolander's bluegrass POBO Poa bolanderi 10–20 – Forb3 Perennial Forbs 25–75 rockcress ARABI2 Arabis 8–25 – white hawkweed HIAL2 Hieracium albiflorum 8–25 – lousewort PEDIC Pedicularis 8–25 – Tree4 Young trees 3–8 mountain hemlock TSME Tsuga mertensiana 3–5 – California red fir ABMA Abies magnifica 1–3 – western white pine PIMO3 Pinus monticola 1–3 – Interpretations
Animal community
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.
Western white pine provides habitat for a variety of mammals, aviafauna, and insects The seeds of western white pine are an important part of the diet of red squirrels and deer mice. Blue grouse prefer western white
pine needles over those of western hemlock.
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 site is used for hiking, and cross country skiing.
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 ceilingsOther 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.
Cones of western white pine are collected for novelty items.Supporting information
Type locality
Location 1: Alpine County, CA Latitude 38° 40′ 12″ Longitude 119° 57′ 39″ General legal description Toiyabe National Forest. Other references
Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). http://www.fs.fed.us/database/feis/plants/tree/tsumer/fire_ecology.html
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.
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
Angela Mushrush
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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