Ecological site F006XC001WA

F006XA004WA	Cold Cryic Xeric Mountain Slopes (Subalpine fir Cold Dry Shrub) On colder, higher elevation sites. Has grouse whortleberry in the understory.
F006XA003WA	Cryic Xeric Mountain Slopes (Subalpine fir Cool Moderately Dry Shrub/Herb) Lower elevation and warmer

F006XA001WA	Cool Frigid Xeric Ashy Slopes (Douglas-fir Cool Dry Grass) On warmer, lower elevation sites.
F006XD002WA	Cool Frigid Xeric Ashy Slopes (Grand fir Cool Dry Grass) On warmer, lower elevation sites.

Tree	(1) Abies lasiocarpa
Shrub	Not specified
Herbaceous	(1) Calamagrostis rubescens

Landforms	(1) Mountains > Mountain slope (2) Plateau > Plateau
Flooding frequency	None
Ponding frequency	None
Elevation	4600 – 6000 ft
Slope	10 – 65 %
Water table depth	0 – 80 in
Aspect	W, NW, N, NE, E, SE, S, SW

Flooding frequency	Not specified
Ponding frequency	Not specified
Elevation	3200 – 7000 ft
Slope	0 – 90 %
Water table depth	0 – 80 in

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

Surface texture	(1) Ashy fine sandy loam (2) Ashy sandy loam
Family particle size	(1) Ashy-skeletal (2) Ashy (3) Ashy over loamy (4) Loamy-skeletal
Drainage class	Well drained
Depth to restrictive layer	20 – 60 in
Surface fragment cover <=3"	0 – 25 %
Surface fragment cover >3"	0 – 16 %
Available water capacity (0-40in)	2.2 – 6.9 in
Calcium carbonate equivalent (Depth not specified)	Not specified
Electrical conductivity (Depth not specified)	Not specified
Sodium adsorption ratio (Depth not specified)	Not specified
Soil reaction (1:1 water) (0-40in)	4.5 – 7.3
Subsurface fragment volume <=3" (Depth not specified)	17 – 40 %
Subsurface fragment volume >3" (Depth not specified)	2 – 34 %

Ecological dynamics

These are the warmest of the subalpine fir ecological sites. Elevation ranges from less than 2,880 to 5,700 feet. Most landscape locations are upper to middle slopes on warmer south to west landscapes. A big distinction in these sites is ponderosa pine can be more than a minor component in the stand. This site compasses three USFS plant associations: ABLA/CARU, ABLA/PAMY/CARU, and ABLA/PAMY. Its biophysical designation is Subalpine fir Cool Dry Grass. Pinegrass (CARU) will be the dominant herb and form a dominant sod bound condition in CARU sites. In the PAMY/CARU and PAMY (pachistima) sites shrubs will dominate. Douglas-fir, lodgepole pine, and ponderosa pine are the major seral species. Subalpine fir is the shade tolerant climax species usually found in the understory. In the PAMY site western white pine and quaking aspen can be found. The CARU and PAMY/CARU sites are too dry for Engelmann spruce.

Most of this ecological site is located on the north border of CRA 6.4 which occurs at the higher elevation on the north side of Lake Chelan. It also located in adjacent CRA 6.1.
ABLA/CARU sites also occur in CRA 6.7 east of Mt. Adams. They are warmer than the northern sites and have a whole array of shade tolerant and shade intolerant species. Pinegrass and other grasses are the dominant vegetation.

State and transition model

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Ecosystem states

1. Reference

State 1 submodel, plant communities

1.1. Reference PC

1.2. Stand Initiation

1.3. Stem Exclusion

1.4. Understory Reinitiation

1.1B	-	Stand replacing fire
1.2A	-	Time
1.3B	-	Stand replacing fire
1.3A	-	Time
1.4A	-	Time
1.4B	-	Stand replacing fire

State 1
Reference

The stand dynamics depend on whether low intensity fires occur frequently to keep an open stand with older mature Douglas-fir, ponderosa pine, and larch. Scattered subalpine fir, lodgepole pine, and Engelmann spruce may be present. In this condition it looks similar to the Douglas-fir and pinegrass ecological site. If there is long low intensity fire intervals overstory and understory fuel loads buildup a stand replacing fire can revert site back to a grass and shrub site with a lodgepole pine the main regenerating tree species.

In low intensity fires Douglas-fir remains the dominant overstory with some ponderosa pine and larch. This is typical on the pinegrass and pinegrass/Oregon boxleaf boxwood sites. On the Oregon boxleaf boxwood site there is greater tree stocking and mixed severity fires and stand replacing fires are normal. Here there is a mixed forest of Douglas-fir, Engelmann spruce, Western white pine, ponderosa pine, and quaking aspen. On both scenarios subalpine fir is the climax species and is the main overstory and understory component if long fire intervals exist. This seldom occurs. Pinegrass is the dominant herb in the Pinegrass sites and shrubs like pachistima, spirea, serviceberry, scouler willow, rose, and big huckleberry are dominant over pinegrass in the pinegrass/Oregon boxleaf boxwood and Oregon boxleaf boxwood sites.

Dominant plant species

Douglas-fir (Pseudotsuga menziesii), tree
lodgepole pine (Pinus contorta), tree
ponderosa pine (Pinus ponderosa), tree
western larch (Larix occidentalis), tree
subalpine fir (Abies lasiocarpa), tree
Engelmann spruce (Picea engelmannii), tree
western white pine (Pinus monticola), tree
quaking aspen (Populus tremuloides), tree
thinleaf huckleberry (Vaccinium membranaceum), shrub
whortleberry (Vaccinium myrtillus), shrub
Oregon boxleaf (Paxistima myrsinites), shrub
Douglas maple (Acer glabrum var. douglasii), shrub
dwarf rose (Rosa gymnocarpa), shrub
white spirea (Spiraea betulifolia), shrub
Scouler's willow (Salix scouleriana), shrub
Saskatoon serviceberry (Amelanchier alnifolia), shrub
russet buffaloberry (Shepherdia canadensis), shrub
pipsissewa (Chimaphila umbellata), shrub
pinegrass (Calamagrostis rubescens), grass
western rattlesnake plantain (Goodyera oblongifolia), other herbaceous
heartleaf arnica (Arnica cordifolia), other herbaceous
lupine (Lupinus), other herbaceous

Community 1.1
Reference PC

Frequent ground fires create an open stand of mature Douglas-fir with some western larch, ponderosa pine, and lodgepole pine. Pinegrass dominates the understory. This is perpetuated with continual ground fires. In the Oregon boxleaf boxwood sites mixed severity fires create a mixed species stand with pachistima and other shrubs dominating the understory. Subalpine fir is the main regeneration species with long fire intervals. Frequent ground fires favor Douglas-fir, ponderosa pine, and western larch. Severe stand replacing fires favor quick lodgepole pine establishment.

Resilience management. Plant Community Pathway 1.1A Frequent ground fires maintain open stand.

Community 1.2
Stand Initiation

Frequent ground fires would reduce subalpine fir regeneration and favor scattered Douglas-fir, ponderosa pine, western larch, and lodgepole pine. Lack of fire would favor subalpine fir and Engelmann spruce (Oregon boxleaf boxwood sites). Severe fires would favor lodgepole pine.

Pinegrass would dominate the understory in frequent ground fires on pinegrass sites. In shrub dominated Oregon boxleaf boxwood sites shrubs would re-sprout and increase.

Community 1.3
Stem Exclusion

Dense stands of mixed species or lodgepole pine depending on fire severity.

Community 1.4
Understory Reinitiation

Dense stand thins out from competition and insect/disease mortality allowing understory tree regeneration and pinegrass or shrub species to increase. Stands could be mixed or composed of mainly lodgepole pine. Subalpine fir and Engelmann spruce (Oregon boxleaf boxwood sites) would be main regeneration.

Pathway 1.1B
Community 1.1 to 1.2

Stand replacing fire due to lack of frequent ground fires and fuel load buildup.

Pathway 1.2A
Community 1.2 to 1.3

Time. Tree regeneration grows into dense stands.

Pathway 1.3B
Community 1.3 to 1.2

Stand replacing fire back to plant community phase 1.2

Pathway 1.3A
Community 1.3 to 1.4

Time. Dense stands grow and thin out creating canopy gaps. Understory vegetation and tree regeneration increases.

Pathway 1.4A
Community 1.4 to 1.1

Time. Tree overstory matures. Frequent fires create open stand with old Douglas-fir. Mixed severity fires create a mosaic of mixed tree species. Severe fire creates an old lodgepole pine stand. Subalpine fir is major regeneration species.

Pathway 1.4B
Community 1.4 to 1.2

Stand replacing fire back to plant community phase 1.2. This could be perpetuated by consistent lodgepole pine establishment and burns.

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 7. Community 1.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 8. Community 1.3 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 9. Community 1.4 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Common name	Symbol	Site index low	Site index high	CMAI low	CMAI high	Age of CMAI	Site index curve code	Site index curve basis
Douglas-fir	PSME	50	92	29	109	116	–	–
ponderosa pine	PIPO	63	92	49	88	55	–	–
lodgepole pine	PICO	55	75	43	79	100	–	–
subalpine fir	ABLA	55	75	44	70	125	–	–
Engelmann spruce	PIEN	80	–	76	–	100	–	–

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	04/01/2025
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 F006XC001WA

Cryic Xeric Mountain Slopes and Plateaus (Subalpine fir Cool Dry Grass)

Last updated: 4/01/2025 Accessed: 07/27/2026

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General information

MLRA notes

LRU notes

Classification relationships

Ecological site concept

Associated sites

Similar sites

Table 1. Dominant plant species

Natural Resources
Conservation Service

Cryic Xeric Mountain Slopes and Plateaus
(Subalpine fir Cool Dry Grass)

Last updated: 4/01/2025
Accessed: 07/27/2026