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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Classification relationships
Holland, R.F. 1986. Preliminary descriptions of the terrestrial natural communities of California. Unpublished report. State of California, The Resources Agency, Department of Fish and Game, Natural Heritage Division, Sacramento, CA. (Updated September 2003). Element Code: Aspen/ Big Sagebrush 61.111.06.
Sawyer, J.O. and T. Keeler-Wolf. 1995. A Manual of California Vegetation. California Native Plant Society, Sacramento, CA. Aspen Series.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Populus tremuloides
(2) Artemisia tridentata ssp. vaseyanaHerbaceous (1) Bromus marginatus
Physiographic features
This site occurs on mountain sideslopes. Slope range from 4 to 50 percent but 8 to 30 percent is typical. Elevations range from 5600 to 8600 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 5600 – 8600 ft Slope 4 – 50 % Water table depth 40 – 50 in Aspect Aspect is not a significant factor Climatic features
The climate of this site is temperate, characterized by warm, dry summers and cold, moist winters. The area's precipitation comes mostly from winter Pacific cyclonic storms, with a very slight summer monsoonal season that is erratic but can be locally significant. Average annual precipitation is 30 to 50 inches with most occurring during the winter months. Approximately half the precipitation falls as snow; half as rain. The mean annual air temperature is 38 to 44 degrees F. The average growing season is about 30 to 60 days.
Table 3 Representative climatic features
Frost-free period (average) 60 days Freeze-free period (average) 0 days Precipitation total (average) 50 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
This site occurs on deep, well drained soils that formed in volcanic ash and colluvium over residuum derived from tuff and andesite. These soils are usually moist in winter, spring, and early summer, dry later in summer and fall. Soils are saturated for brief perios below 30 inches during snowmelt. These soils have high amounts of vitric volcanic ash and glass throughout the soil profile whigh enhances the water holding capacity of these soils. Soil series associated with this site include Pyropatti.
Table 4. Representative soil features
Parent material (1) Volcanic ash – tuff
Surface texture (1) Gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 40 – 60 in Surface fragment cover <=3" 24 – 25 % Surface fragment cover >3" 0 – 2 % Available water capacity
(0-40in)6.6 – 6.7 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)6.1 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)24 – 46 % Subsurface fragment volume >3"
(Depth not specified)2 – 3 % Ecological dynamics
Where management results in abusive livestock use, the aspen overstory can be thinned out and permanent openings in the canopy may be created. If aspen sucker reproduction is inadequate to replace overstory mortality, snowberry, big sagebrush and other shrubs increase and eventually become dominant.
Fire effects:
The most important agent of disturbance in aspen forests before 1900 was fire, although other natural disturbances were locally important including windthrow, snow damage, hail, lightning, fungal diseases and insect damage. Most aspen forests in the West are seral and have been dependent upon fire for their perpetuation. If fire occurs at infrequent intervals (e.g. 50-150 years) and is intense enough to kill most of the aspen and competing conifers, them most aspen sites in the West will retain viable stands of aspen. Periodic wildfires prevent over-mature aspen stands and maintain a naturally stratified mosaic of even-aged aspen communities in various stages of successional development. Uneven-aged stands form under stable conditions where the overstory gradually disintegrates with disease or age, and is replaced by aspen suckers. Although aspen forests do not burn readily, aspen trees are extremely sensitive to fire. A severe fire will top-kill the aspen overstory and will stimulate abundant suckering. A severe fire also removes the duff and may kill roots. Repeated fires have a detrimental effect on site quality and can eliminate aspen from a site.
Aspen is highly competitive on burned sites and has several adaptations to fire including the following: a) the thin bark has little heat resistance, and aspen is easily top-killed by fire, b) root systems of top-killed stems send up a profusion of sprouts for several years after fire, c)sprouts grow rapidly by extracting water, nutrients, and photosynthate from an extant root system, and may outcompete other woody vegetation, d)following fire, a new, even-aged quaking aspen stand can develop within a decade, and e) aspen is self-thinning and a mature forest of healthy trees can develop from dense sprouts.
Mountain big sagebrush is highly susceptible to injury from fire. Plants are readily killed in all seasons, even light severity fires. Mountain big sagebrush plants top-killed by fire will not resprout.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 StateCommunity 1.1
Reference Plant CommunityThe reference plant community is dominated by dense stands of low-growing quaking aspen, generally less than 15-feet tall at maturity (locally known as "snowbank" aspen). Each site normally represents a single clone of aspen with a common genetic makeup. A variety of forbs, mountain brome, needlegrass, slender wheatgrass, and snowberry are important understory species associated with this site and are most prevalent on the periphery of the aspen overstory. Potential vegetative composition is about 20% grasses, 15% forbs and 65% shrubs.
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 1755 2275 3250 Grass/Grasslike 540 700 1000 Forb 405 525 750 Total 2700 3500 5000 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 350–525 mountain brome BRMA4 Bromus marginatus 350–525 – 2 Secondary Perennial Grasses 72–420 needlegrass ACHNA Achnatherum 18–105 – big squirreltail ELMU3 Elymus multisetus 18–105 – slender wheatgrass ELTR7 Elymus trachycaulus 18–105 – bluegrass POA Poa 18–105 – Forb3 Perennial Forbs 216–1260 nettleleaf giant hyssop AGURU Agastache urticifolia var. urticifolia 18–105 – castilla CASTI Castilla 18–105 – Jessica sticktight HAMI Hackelia micrantha 18–105 – owl's-claws HYHO Hymenoxys hoopesii 18–105 – Gray's licorice-root LIGR Ligusticum grayi 18–105 – tailcup lupine LUCAC3 Lupinus caudatus ssp. caudatus 18–105 – cryptantha owl's-clover ORCUC2 Orthocarpus cuspidatus ssp. cryptanthus 18–105 – sweetcicely OSBE Osmorhiza berteroi 18–105 – Brown's peony PABR Paeonia brownii 18–105 – Fendler's meadow-rue THFEF Thalictrum fendleri var. fendleri 18–105 – California valerian VACA2 Valeriana californica 18–105 – woolly mule-ears WYMO Wyethia mollis 18–105 – 4 Annual Forbs 35–210 Shrub/Vine5 Primary Shrubs 245–700 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 175–525 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 70–175 – 6 Secondary Shrubs 105–315 silver sagebrush ARCA13 Artemisia cana 35–105 – rubber rabbitbrush ERNAN5 Ericameria nauseosa ssp. nauseosa var. nauseosa 35–105 – currant RIBES Ribes 35–105 – Tree7 Deciduous Trees 1400–2100 quaking aspen POTR5 Populus tremuloides 1400–2100 – Interpretations
Animal community
Livestock Interpretations:
Livestock utilization of quaking aspen communities vary with species composition of the understory and relative age of the quaking aspen stand. Young stands usually provide the most browse. Quaking aspen crowns can grow out of reach of large ungulates in 6 to 8 years. Although many animals browse quaking aspen year-round, it is especially valuable forage during fall and winter, when protein levels are high relative to other browse species. Mountain brome provide a palatable and nutritious forage for livestock, especially from early spring until seed dispersal.
Stocking rates vary over time depending upon season of use, climate variations, site, and previous and current management goals. A safe starting stocking rate is an estimated stocking rate that is fine tuned by the client by adaptive management through the year and from year to year.
Wildlife Interpretations:
Wildlife utilization of quaking aspen communities varies with understory composition and age of aspen stand. Mountain brome is an important forage for several wildlife species.Hydrological functions
Runoff is medium to high. Hydrologic soil group: B.
Other products
Quaking aspen is widely used in ornamental landscaping.
Other information
Aspens are used to stabilize the soil on disturbed sites. The wide adaptability of quaking aspen makes it well-suited for restoration and rehabilitation projects on a wide range of sites.
Supporting information
Type locality
Location 1: Modoc County, CA Latitude 41° 58′ 55″ Longitude 120° 8′ 41″ General legal description On the Modoc National Forest in the Warner Mountains Other references
Fire Effects Information System [Online]. http://www.fs.fed.us/feis
Miles, S.R. and C.B. Goudey. 1997. Ecological Subregions of California Section and Subsection Descriptions. United States Department of Agriculture Forest Service, Pacific Southwest Region R5-EM-TP-005. Subsection M261Gf-Warner Mountains.
Modoc Elk Working Group. 2000. The Greater Modoc Area A Strategic Plan for Elk Management. Modoc County, CA
Contributors
P.NOVAK-ECHENQUE
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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