Ecological site F044AY505WA

F043AY577ID	Ashy Depressions 30-45" PZ Frigid Clearwater Mountains Sites are on foot slopes and drainageways of mountains, narrow valley floors, and low terraces. Sites are moderately cool and very moist. Textures are loamy with a distinct layer of volcanic ash present at the surface. Overstory species include Thuja plicata and Abies grandis. The understory is typified by shrubs such as Acer glabrum, Rubus parviflorus and by the presence of fern species like Gymnocarpium dryopteris, and Adiantum pedatum.
F043AY584ID	Poorly Drained Floodplain Step 30-45" PZ Frigid Western Bitterroot Foothills Sites are found on large river floodplains. Sites are relatively warm and have high available moisture through subirrigation. They are prone to flooding unless protected. Textures are loamy and materials are mixed by alluvial activity. Sites are often a complex mosaic of trees; like Populus balsamifera ssp. Trichocarpa, and Populus tremuloides; shrubs like Cornus sericea, and Salix spp.; and herbs like Carex spp, and Deschampsia cespitosa.
F044AY504WA	Frigid, Udic, Loamy Foothills and Drainageways, high water table (Western Hemlock/Moist Forbes) Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum Found on hill slopes, terraces and floodplains. Sites have loamy textures and a water table at 30-50cm during spring. Overstory species include Tsuga heterophylla, and Thuja plicata. The understory is typified by Coptis occidentalis, Linnaea borealis ssp. Longiflora, Clintonia uniflora, and Goodyera oblongifolia.

F043AY530WA	Warm-Frigid, Dry-Udic, Sandy Outwash Terraces, mixed ash surface (Grand Fir Moist Herb) Abies grandis/Clintonia uniflora Found warmer, drier sites on sandy outwash terraces. Overstory species are dominantly Abies grandis and Pseudotsuga menziesii var. glauca. The understory is typified by Acer glabrum, Linnaea borealis ssp. Longiflora Clintonia uniflora, and Coptis occidentalis.
F044AY504WA	Frigid, Udic, Loamy Foothills and Drainageways, high water table (Western Hemlock/Moist Forbes) Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum Found on hill slopes, terraces and floodplains. Sites have loamy textures and a water table at 30-50cm during spring. Overstory species include Tsuga heterophylla, and Thuja plicata. The understory is typified by subshrubs and forbs including Coptis occidentalis, Linnaea borealis ssp. Longiflora, Clintonia uniflora and Goodyera oblongifolia.

Tree	(1) Tsuga heterophylla (2) Thuja plicata
Shrub	(1) Coptis occidentalis (2) Linnaea borealis ssp. longiflora
Herbaceous	(1) Clintonia uniflora (2) Goodyera oblongifolia

Landforms	(1) Foothills > Flood plain (2) Valley > Outwash terrace (3) Valley > Stream terrace (4) Mountains > Flood plain
Flooding frequency	None
Ponding frequency	None
Elevation	1770 – 1800 ft
Slope	1 – 10 %
Aspect	NE, E, SE

Flooding frequency	None to occasional
Ponding frequency	None
Elevation	1755 – 1870 ft
Slope	0 – 25 %

Frost-free period (characteristic range)	140-140 days
Freeze-free period (characteristic range)
Precipitation total (characteristic range)	20-20 in
Frost-free period (actual range)	130-140 days
Freeze-free period (actual range)
Precipitation total (actual range)	20-30 in

Parent material	(1) Alluvium – granite
Surface texture	(1) Loamy fine sand
Drainage class	Somewhat excessively drained
Permeability class	Rapid
Available water capacity (0-40in)	2.6 in
Calcium carbonate equivalent (0-60in)	Not specified
Soil reaction (1:1 water) (0-60in)	Not specified
Subsurface fragment volume <=3" (10-40in)	5 %

Drainage class	Somewhat excessively drained
Permeability class	Rapid to very rapid
Available water capacity (0-40in)	1.8 – 3 in
Calcium carbonate equivalent (0-60in)	0 %
Soil reaction (1:1 water) (0-60in)	6.5 – 6.9
Subsurface fragment volume <=3" (10-40in)	0 – 10 %

Common name	Symbol	Site index low	Site index high	CMAI low	CMAI high	Age of CMAI	Site index curve code	Site index curve basis
western white pine	PIMO3	60	93	118	180	100	–	–
grand fir	ABGR	60	98	76	149	100	–	–
western larch	LAOC	56	85	74	132	70	–	–
Rocky Mountain Douglas-fir	PSMEG	72	85	83	116	110	–	–
Rocky Mountain Douglas-fir	PSMEG	66	100	71	97	90	–	–

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	06/04/2026
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 F044AY505WA

Frigid, Udic, Sandy Hill slopes and Outwash terraces (Western Hemlock/Moist Forbes) Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum

Last updated: 9/07/2023 Accessed: 06/04/2026

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Classification relationships

Ecological site concept

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Table 1. Dominant plant species

Natural Resources
Conservation Service

Frigid, Udic, Sandy Hill slopes and Outwash terraces
(Western Hemlock/Moist Forbes)
Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum

Last updated: 9/07/2023
Accessed: 06/04/2026