Ecological site F043CY508WA

F043CY503WA	Frigid, Moist-Xeric Loamy, Canyons and Mountains (Grand fir/Moist Shrub) frigid, moist-xeric, ashy surface, basalt/andesite geology.
F043CY504WA	Warm-Frigid, Xeric, Loamy, Basalt Mountains and Plateaus (Douglas-fir/warm dry shrub) warm-frigid, xeric, mixed ash surface, basalt geology.

F043CY509WA	Frigid, Xeric, Loamy Mountains and Plateaus, Ashy Surface Grand fir/pinegrass Ashy surface
F043CY503WA	Frigid, Moist-Xeric Loamy, Canyons and Mountains (Grand fir/Moist Shrub) Moist-xeric soil moisture regime
F043CY502WA	Cool-Frigid, Dry-Xeric, Loamy Mountains (Douglas-fir Cool Dry Grass) Cool-frigid soil temperature regime, dry-xeric soil moisture regime

Tree	(1) Abies grandis (2) Pseudotsuga menziesii var. glauca
Shrub	(1) Chimaphila umbellata (2) Mahonia repens
Herbaceous	(1) Calamagrostis rubescens (2) Carex geyeri

Landforms	(1) Mountains > Mountain slope (2) Plateau > Plateau
Flooding frequency	None
Ponding frequency	None
Elevation	3770 – 4705 ft
Slope	55 – 75 %
Water table depth	0 in
Aspect	W, NW, N, NE

Flooding frequency	Not specified
Ponding frequency	Not specified
Elevation	2410 – 6100 ft
Slope	20 – 100 %
Water table depth	0 in

Frost-free period (characteristic range)	80-100 days
Freeze-free period (characteristic range)
Precipitation total (characteristic range)	30-50 in
Frost-free period (actual range)	70-130 days
Freeze-free period (actual range)
Precipitation total (actual range)	20-60 in
Frost-free period (average)	90 days
Freeze-free period (average)
Precipitation total (average)	40 in

Parent material	(1) Volcanic ash (2) Loess (3) Residuum – basalt (4) Colluvium – basalt (5) Residuum – andesite (6) Colluvium – andesite
Surface texture	(1) Ashy silt loam (2) Ashy loam (3) Ashy clay loam
Drainage class	Well drained
Permeability class	Moderately slow
Depth to restrictive layer	38 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	4.8 in
Calcium carbonate equivalent (0-60in)	Not specified
Soil reaction (1:1 water) (0-60in)	Not specified
Subsurface fragment volume <=3" (10-60in)	20 %
Subsurface fragment volume >3" (10-60in)	25 %

Drainage class	Well drained
Permeability class	Slow to moderate
Depth to restrictive layer	20 – 0 in
Surface fragment cover <=3"	0 %
Surface fragment cover >3"	0 %
Available water capacity (0-40in)	3.5 – 6.2 in
Calcium carbonate equivalent (0-60in)	0 %
Soil reaction (1:1 water) (0-60in)	5.6 – 7.3
Subsurface fragment volume <=3" (10-60in)	3 – 50 %
Subsurface fragment volume >3" (10-60in)	6 – 80 %

Ecological dynamics

ECOLOGICAL DYNAMICS OF THE SITE
This site is almost exclusively made up of the grand fir (Abies grandis)/pinegrass (Calamagrostis rubescens) plant association (ABGR/CARU). Very minor occurrences of the grand fir/elk sedge (Carex geyeri) (ABGR/CAGE) plant association, and cold pocket lodgepole pine (Pinus contorta) may be found together with with the major plant association. ABGR/CARU is a part of the broader warm dry upland forest plant association group (PAG), and the dry upland forest potential vegetation group (PVG) 1.
This dry grand fir forest type occurs above Ponderosa pine (Pinus ponderosa) forest types on a moisture gradient. It is in turn transitional to the mesic mixed (in LANDFIRE2 terminology) conifer types. In the historic, naturally occurring ecological condition, Ponderosa pine is usually the long-lived dominant species in a fire-maintained stand. Other conifers found in this ecologic site include grand fir, Douglas-fir (Pesudotsuga menziesii) and western larch (Larix occidentalis). Western larch is commonly limited in diameter growth due to the late season temperature/moisture limitations which occur within this seasonally dry ecological site.
Frequent, low intensity surface fires (also called “under-burns”) maintained widely spaced stands of fire-resistant conifers in older, more open stands. Less frequently occurring mixed-severity and stand replacement fires resulted in mosaics of older and larger trees, intermingled with younger patches of regenerating forests. The early development (i.e. regeneration) phase of this ecological site was dominated by Ponderosa pine and larch seedlings, mixed with fire tolerant grasses, sedges and shrub species such as ceanothus spp., scouler willow (Salix scouleriana) and Bromus spp.
Young, newly regenerated stands would usually progress to mid-development phases in time. The stands were dominated by large pole to small and intermediate sawtimber sized individual conifers. Individual stands expressed varying degrees of canopy closure(s) depending on initial seedling and stocking rates, coupled with the impacts of disturbance events that occurred over the course of development. Mid-development stands could in turn progress to mature stands with the passing of additional time and under favorable conditions. In the absence of surface fire, shade tolerant grand fir will begin to dominate the understory conifer layer (this is now a common and wide spread condition, the direct result of a policy of total fire suppression which was implemented in the Post-European era of settlement in the western United States).
Although fire was the major disturbance factor in the historic context in this ecological site, insects (such as bark beetles and defoliators) and root diseases also impacted the forest at any given time. Less frequent wind events and lighting also occurred, locally altering stand structural and functional attributes.

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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	04/21/2026
Approved by
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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:
Perennial plant reproductive capability:

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Natural ResourcesConservation Service

Ecological site F043CY508WA

Frigid, Xeric, Loamy, Mountains and Plateaus, Mixed Ash Surface Grand fir/pinegrass

Last updated: 9/08/2023 Accessed: 04/21/2026

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Table 1. Dominant plant species

Natural Resources
Conservation Service

Frigid, Xeric, Loamy, Mountains and Plateaus, Mixed Ash Surface
Grand fir/pinegrass

Last updated: 9/08/2023
Accessed: 04/21/2026