Ecological site F006XY706OR

R006XB102OR	Cold Wet Meadow Occupying adjacent low energy meadows rather than higher energy floodplains and low terraces along streams

R006XB102OR	Cold Wet Meadow Occupying low energy meadows rather than higher energy floodplains and low terraces along streams

Tree	(1) Picea engelmannii
Shrub	(1) Alnus incana
Herbaceous	Not specified

Landforms	(1) Stream terrace (2) Flood plain
Flooding duration	Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours)
Flooding frequency	Rare to occasional
Ponding frequency	None
Elevation	1219 – 1829 m
Slope	0 – 3 %
Ponding depth	0 cm
Water table depth	0 – 152 cm
Aspect	Aspect is not a significant factor

Frost-free period (characteristic range)	10-50 days
Freeze-free period (characteristic range)
Precipitation total (characteristic range)	640-1,020 mm
Frost-free period (average)	30 days
Freeze-free period (average)
Precipitation total (average)	810 mm

Parent material	(1) Alluvium – volcanic rock
Surface texture	(1) Ashy fine sandy loam
Family particle size	(1) Sandy
Drainage class	Somewhat poorly drained
Permeability class	Rapid
Depth to restrictive layer	152 – 203 cm
Soil depth	152 – 203 cm
Surface fragment cover <=3"	0 – 15 %
Surface fragment cover >3"	0 – 5 %
Available water capacity (0-101.6cm)	9.4 – 16 cm
Soil reaction (1:1 water) (0-101.6cm)	5.6 – 7.3
Subsurface fragment volume <=3" (10.2-152.4cm)	10 – 35 %
Subsurface fragment volume >3" (10.2-152.4cm)	0 – 5 %

Ecological dynamics

Ecological dynamics and disturbance:

Present knowledge of these dynamics is incomplete for this site, but fire and alterations of adjacent stream channels will influence plant community composition, productivity and succession. Natural transitions from alluvial bars to floodplains will decrease mountain alder and favor the development of Engelmann spruce overtime. This occurs with the aggradation of fine-textured soil surface layers over coarse-textured materials thereby promoting the establishment of forested floodplains (Crowe et al. 2004). Fire was likely an infrequent form of disturbance on this site. Following severe fire, shrub cover may increase along with herbaceous species. Water tables may also raise following fire yet site transitions following this process are likely ephemeral (Kovalchik 1987). Timber harvest is uncommon on these sites due to proximity to stream channels and wet soils. Livestock grazing is sometimes present on this site, yet resulting alterations in vegetative composition are unclear. Care should be taken to avoid livestock grazing when soils are wet.

Emerging evidence is suggesting that climate change is leading to hotter and drier conditions in western forests that will increase fire frequency and extent and lengthen fire seasons (Halofsky et al. 2020). When combined with the interacting impacts of fire suppression, drought, and insect outbreaks, it is possible that this ecological system will experience unpredictable ecosystem shifts and additional alternative states.

State and transition model

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Ecosystem states

1. Historic Reference

State 1 submodel, plant communities

1.1. Reference plant community

1.2. Alder dominated community

1.3. Shrub/herb community

1.1A	-	Floodplain degradation, soil loss
1.1B	-	Severe fire removing overstory canopy
1.2A	-	Extended time in the presence of sufficient sediment loads upstream and channel and vegetation structure that permits aggradation
1.3A	-	Time will allow Engelman spruce to recolonize the site

State 1
Historic Reference

The reference plant community for this site is defined by the overstory dominance of Engelmann spruce (Picea englemannii) in association with mountain alder (Alnus incana). Understory herb and shrub species will depend on water table depth and seasonality. A diverse, herbaceous understory may often include common horsetail (Equisetum arvense), twistedstalk (Streptopus amplexifolius), monkshood (Aconitum sp.), wintergreen (Pyrola sp.), sedges (Carex sp.), prince's pine (Chimaphila umbellata), queencup beadlilly (Clintonia uniflora), starry solomonplume (Maianthemum stellatum) and bedstraw (Galium sp.). White fir (Abies concolor) and grand fir (Abies grandis) may be subdominant in the canopy and may increase within dry microsites along with lodgepole pine (Pinus contorta). Mountain alder may grow as a shrub or a tree. Other shrub species may include currants (Ribes spp.), and red-osier dogwood (Cornus sericea). Adjacent streambanks and meadows may host additional shrubs that may include snowberry (Symphoricarpos spp.), rose (Rosa spp.), spiraea (Spiraea sp.) and gooseberry (Ribes spp.).

Dominant plant species

Engelmann spruce (Picea engelmannii), tree
gray alder (Alnus incana), shrub

Community 1.1
Reference plant community

Forested overstory dominated by Engelmann spruce

Community 1.2
Alder dominated community

Following degradation and erosion of fine textured soils, mountain alder may become dominant.

Community 1.3
Shrub/herb community

Following severe fire, shrub and herb species will dominate the site.

Pathway 1.1A
Community 1.1 to 1.2

Floodplain degradation, soil loss

Pathway 1.1B
Community 1.1 to 1.3

Severe fire removing overstory canopy

Pathway 1.2A
Community 1.2 to 1.1

Extended time in the presence of sufficient sediment loads upstream and channel and vegetation structure that permits aggradation

Pathway 1.3A
Community 1.3 to 1.1

Time will allow Engelman spruce to recolonize the site

Additional community tables

Table 5. Community 1.1 plant community composition

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

Table 6. Community 1.2 plant community composition

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

Table 7. Community 1.3 plant community composition

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

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	02/14/2025
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:

Download reference sheet

Natural ResourcesConservation Service

Ecological site F006XY706OR

Cryic Coniferous Flood Plain

Last updated: 4/01/2025 Accessed: 04/22/2026

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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

Last updated: 4/01/2025
Accessed: 04/22/2026