Ecological site F043AY585WA

Tree	(1) Pseudotsuga menziesii var. glauca (2) Pinus ponderosa
Shrub	(1) Symphoricarpos albus (2) Physocarpus malvaceus
Herbaceous	(1) Calamagrostis rubescens (2) Bromus vulgaris

Landforms	(1) Valley > Outwash terrace (2) Mountains > Kame (3) Sand plain > Dune (4) Valley > Kame terrace
Elevation	2095 – 3280 ft
Slope	7 – 35 %
Water table depth	0 in
Aspect	Aspect is not a significant factor

Elevation	1290 – 5045 ft
Slope	0 – 70 %
Water table depth	0 in

Parent material	(1) Volcanic ash (2) Loess (3) Outwash (4) Lacustrine deposits
Surface texture	(1) Gravelly, ashy sandy loam (2) Loamy fine sand (3) Very gravelly loamy coarse sand (4) Loamy sand
Drainage class	Somewhat excessively drained
Permeability class	Moderately rapid
Depth to restrictive layer	Not specified
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	2.6 in
Calcium carbonate equivalent (0-60in)	Not specified
Electrical conductivity (0-60in)	Not specified
Sodium adsorption ratio (0-60in)	Not specified
Soil reaction (1:1 water) (0-60in)	6.7
Subsurface fragment volume <=3" (10-60in)	31 %
Subsurface fragment volume >3" (10-60in)	7 %

Drainage class	Well drained to excessively drained
Permeability class	Moderate to very rapid
Depth to restrictive layer	0 in
Surface fragment cover <=3"	0 %
Surface fragment cover >3"	0 %
Available water capacity (0-40in)	0.9 – 5 in
Calcium carbonate equivalent (0-60in)	0 %
Electrical conductivity (0-60in)	0 mmhos/cm
Sodium adsorption ratio (0-60in)	0
Soil reaction (1:1 water) (0-60in)	6.1 – 7.8
Subsurface fragment volume <=3" (10-60in)	0 – 75 %
Subsurface fragment volume >3" (10-60in)	0 – 70 %

Ecological dynamics

The reference state occurred before European settlement when frequent low intensity fires created open stands of large ponderosa pine with a grass dominated understory of pinegrass. Patches of Douglas-fir regeneration will be present. On the lower foothills this ecological site occurs on north and east slopes. On upper mountainous terrain it will occur on southern and western aspects. The model soil characteristics will be loamy over till or mixed colluvium. Sites escaping frequent fire will have a patchy mosaic of older large trees with patches of regeneration, pole stands of ponderosa pine and Douglas-fir, and a mixture of shrubs, grasses and forbs. Bark beetle and root disease mortality will create snags and woody debris. Severe stand replacing fires can result in ceanothus shrub fields dominating for several years until natural regeneration of pine and Douglas-fir reclaim the site. In other less severe burned areas, grass and sedge species will dominate along with sprouting shrubs like ninebark, oceanspray, and snowberry. This ecological site is similar to the Douglas-fir – Ponderosa pine – Western Larch / pinegrass ecological site (Douglas-fir Cool Dry Grass), however the presence of western larch is rare on the model site. This site being warmer and not adequate for larch growth. The Douglas-fir Cool Dry Grass ecological site climate is cooler located at higher elevations allowing western larch to become a prominent stand component in mature stands.
Lack of fire or fire exclusion crosses a threshold and the site goes to another state. State 2 results in homogenous multi-storied stands of ponderosa pine and Douglas-fir with dense understories of regeneration and/or shrubs. Snags and wood debris are lacking. These stands are highly susceptible to stand replacing fires. Much of the acreage of this ecological site is in this condition. Timber stand improvement and fuel removal treatments along with prescribed fire can restore this site to a more open patchy landscape more resistant to severe fire.
In Alternative State 3 severe fire has damaged soil nutrient capacity with shrub fields of ceanothus species dominating the site for 50+ years. This condition more commonly occurring on south and west facing slopes. Restoration activities must be scrutinized on a site by site basis.
In Alternative State 4 some of the lower landscape portions of this ecological site have been converted to introduced grass pastures or annual cropland. Restoring this site to the reference state takes major inputs in site preparation, tree planting, vegetation control, fuels management and other silvicultural treatments.

State and transition model

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Standard diagram

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Additional community tables

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	08/10/2026
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 F043AY585WA

Warm-Frigid, Xeric, Sandy, Outwash Terraces (Douglas-fir Warm Dry Shrub)

Last updated: 10/14/2020 Accessed: 08/10/2026

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General information

MLRA notes

LRU notes

Classification relationships

Ecological site concept

Figure 1.

Figure 2.

Table 3. Dominant plant species

Natural Resources
Conservation Service

Warm-Frigid, Xeric, Sandy, Outwash Terraces
(Douglas-fir Warm Dry Shrub)

Last updated: 10/14/2020
Accessed: 08/10/2026