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Ecological site AX001X01X308

Cryic Alpine Tundra

Last updated: 5/15/2025
Accessed: 05/19/2025

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General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 001X–Northern Pacific Coast Range, Foothills, and Valleys

This area consists of a long and narrow range of mountains with associated foothills and valleys that parallels the Pacific Ocean. This area is entirely within the Pacific Border Province of the Pacific Mountain System in Oregon and Washington. MLRA 1 is bounded on the north by the highest elevations of the Olympic Mountains and the strait of Juan de Fuca, and by the Klamath Mountains on the south. The Washington portion of this MLRA is primarily composed of young Tertiary sedimentary rocks (siltstone and sandstone) mixed with some volcanic rocks of the same age. Glacial till and outwash deposits are also found in the northern half of this area in Washington. Much of this area is accreted terrane formed by tectonic processes. The average annual precipitation ranges from 60 to 200 inches (1,525 to 5,580 millimeters), increasing with elevation. Most of the precipitation in this area occurs during low-intensity, Pacific frontal storms and is evenly distributed throughout fall, winter, and spring.

The dominant soil orders in this MLRA are Andisols, Inceptisols, and Ultisols. Soil depths broadly range from shallow to very deep. Soils are primarily well drained, however poorly drained soils may be found in depressional areas and on alluvial floodplains. Surface textures are typically medial and loamy or clayey. Soils in this area dominantly have a mesic or frigid temperature regime and a udic moisture regime. Soils with aquic moisture regimes and cryic temperature regimes also occur.

Ecological site concept

Cryic Alpine Tundra sites occur on aretes at elevations above 1,400 meters (4,593 feet). These sites are found above the tree line where conditions generally preclude tree establishment. These sites are found scattered throughout high elevation areas. Sites are dominated by dwarf shrubs including pink mountainheath (Phyllodoce empetriformis) and western moss heather (Cassiope mertensiana), with some forbs and graminoids present. Scattered krummholz tree may be observed on this site depending on site elevation and conditions.

Associated sites

AX001X01X305	Cryic Udic Wet Subalpine Meadow Cryic Udic Wet Subalpine Meadow sites may be found on more stable landscape positions downslope from Cryic Alpine Tundra sites. Cryic Udic Wet Subalpine Meadow sites have seasonally high water tables. Increased effective precipitation encourages high productivity on Cryic Udic Wet Subalpine Meadow sites.
AX001X01X306	Cryic Aquic Subalpine Wet Meadow Cryic Aquic Subalpine Wet Meadow sites may be found on seeps and depressions on more stable landscape positions downslope from Cryic Alpine Tundra sites. Cryic Aquic Subalpine Wet Meadow sites are subject to frequent ponding for long duration.

AX001X01X305

Cryic Udic Wet Subalpine Meadow

Cryic Udic Wet Subalpine Meadow sites may be found on more stable landscape positions downslope from Cryic Alpine Tundra sites. Cryic Udic Wet Subalpine Meadow sites have seasonally high water tables. Increased effective precipitation encourages high productivity on Cryic Udic Wet Subalpine Meadow sites.

AX001X01X306

Cryic Aquic Subalpine Wet Meadow

Cryic Aquic Subalpine Wet Meadow sites may be found on seeps and depressions on more stable landscape positions downslope from Cryic Alpine Tundra sites. Cryic Aquic Subalpine Wet Meadow sites are subject to frequent ponding for long duration.

Similar sites

AX001X01X302	Cryic Udic Dry Subalpine Meadow Cryic Udic Dry Subalpine Meadow sites generally occur at lower elevations and have greater total plant cover.
AX001X01X301	Cryic Udic Shallow Subalpine Meadow Cryic Udic Shallow Subalpine Meadow sites generally occur at lower elevations. Cryic Udic Shallow Subalpine Meadow sites support more diverse shrub, forb, and graminoid communities.

AX001X01X302

Cryic Udic Dry Subalpine Meadow

Cryic Udic Dry Subalpine Meadow sites generally occur at lower elevations and have greater total plant cover.

AX001X01X301

Cryic Udic Shallow Subalpine Meadow

Cryic Udic Shallow Subalpine Meadow sites generally occur at lower elevations. Cryic Udic Shallow Subalpine Meadow sites support more diverse shrub, forb, and graminoid communities.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Phyllodoce empetriformis (2) Cassiope mertensiana
Herbaceous	(1) Luetkea pectinata (2) Antennaria lanata

Legacy ID

R001XA308WA

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Physiographic features

This site primarily occurs on glacial valley walls on mountains. Cryic Alpine Tundra sites are typically quite steep and unstable, with mass-movement events being common. A significant amount of moisture from precipitation is lost via run-off downslope.

Table 2. Representative physiographic features

Landforms	(1) Mountains > Glacial-valley wall
Flooding frequency	None
Ponding frequency	None
Elevation	4,593 – 6,562 ft
Slope	100%
Water table depth	59 in
Aspect	W, NW, N, NE, E, SE, S, SW

Climatic features

This site occurs in a cryic temperature and udic moisture regime. Precipitation arrives mostly via low-intensity, Pacific frontal storms. Precipitation is unevenly distributed, with the lowest amounts on the leeward side of the Coast Range mountains. Precipitation falls largely as snow in higher elevations. Precipitation is evenly distributed throughout the fall, winter, and spring, while summers are dry. Air temperatures vary significantly along the elevation gradient.

Table 3. Representative climatic features

Frost-free period (characteristic range)	30-60 days
Freeze-free period (characteristic range)
Precipitation total (characteristic range)	118-157 in

Soil features

The soils that support this ecological site occur in the cryic soil temperature regime and the udic soil moisture regime. Hangingglacier soils are moderately deep, well-drained, formed from residuum, and occur on mountaintops and cirques. These soils occur at the highest elevations of all the soils in Olympic National Park and are very susceptible to wind, water, and gravitational erosion. Saturated hydraulic conductivity is high or very high throughout, and rock fragment content is greater than 35 percent in the control section. Although representative of this site, these soils may exist across multiple ecological sites because of naturally variable slope, texture, rock fragments, and pH. An on-site soil pit and the most current ecological site key are necessary to classify a site.

Table 4. Representative soil features

Parent material	(1) Residuum
Surface texture	(1) Gravelly silt loam (2) Gravelly loam (3) Gravelly sandy loam
Soil depth	20 – 39 in
Surface fragment cover <=3"	30%
Surface fragment cover >3"	50 – 70%
Available water capacity (0-40in)	1.5 – 2.4 in
Soil reaction (1:1 water) (0-10in)	4.5 – 5.5
Subsurface fragment volume <=3" (0-20in)	10%
Subsurface fragment volume >3" (0-20in)	5%

Ecological dynamics

The Cryic Alpine Tundra site is found at high elevations in the park where snowpack persists long into the spring and summer. Long-duration snowpack cover significantly reduces growing degree days on site. These sites are typically located on gentle to moderate upper slopes and produce runoff water that is captured by downslope, stable Moist Subalpine Meadow, Wet Subalpine Meadow, and Aquic Subalpine Meadow sites.

Cryic Alpine Tundra sites are subject to severe disturbance from wildfire, avalanches, and mass-movement events. The fire regime of this site likely resembles that of adjacent and lower High Cryic Udic Forest sites that are characterized by high-intensity burns with a long return interval of greater than 200 years (FEIS). Historical fires would likely begin in lower-elevation forests and move upslope to these shrubland sites. When fire does occur, burns are often patchy and low-extent due to discontinuous fuels. Cryic Alpine Tundra sites are susceptible to avalanches and mass-movement events. Powerful avalanches may remove trees and hard-stemmed shrubs from the site and create early seral conditions favorable for the establishment of graminoids and forbs. Mass movement can occur on unstable slopes and remove all or nearly all vegetation from the site.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference

State 1 submodel, plant communities

1.1. Pink Mountainheath, Western Moss Heather, Partridgefoot, and Woolly Pussytoes

1.2. American Bistort and Piper's Woodrush

1.1A	-	High-intensity disturbance
1.2A	-	Time without disturbance

State 1
Reference

The Reference state is comprised of two communities, one a late seral stage, and one occurring in the early aftermath of a disturbance event.

Dominant plant species

pink mountainheath (Phyllodoce empetriformis), shrub
western moss heather (Cassiope mertensiana), shrub
Cascade bilberry (Vaccinium deliciosum), shrub
black crowberry (Empetrum nigrum), shrub
yellow mountainheath (Phyllodoce glanduliflora), shrub
partridgefoot (Luetkea pectinata), other herbaceous
woolly pussytoes (Antennaria lanata), other herbaceous
American bistort (Polygonum bistortoides), other herbaceous
Piper's woodrush (Luzula piperi), other herbaceous
broadleaf lupine (Lupinus latifolius), other herbaceous
Sitka clubmoss (Lycopodium sitchense), other herbaceous
black alpine sedge (Carex nigricans), other herbaceous
showy sedge (Carex spectabilis), other herbaceous
Parry's rush (Juncus parryi), other herbaceous

Community 1.1
Pink Mountainheath, Western Moss Heather, Partridgefoot, and Woolly Pussytoes

Structure: dwarf shrubland with alpine forbs The reference community is dominated by dwarf shrubs, including pink mountainheath (Phyllodoce empetriformis), western moss heather (Cassiope mertensiana), Cascade bilberry (Vaccinium deliciosum), yellow mountainheath (Phyllodoce glanduliflora), and black crowberry (Empetrum nigrum). Found along with these dwarf shrubs is a well-developed alpine forb and graminoid layer consisting of partridgefoot (Luetkea pectinata), woolly pussytoes (Antennaria lanata), broadleaf lupine (Lupinus latifolius), Stika clubmoss (Lycopodium sitchense), black alpine sedge (Carex nigricans), and showy sedge (Carex spectabilis). Bare ground is extensive on this site; exposed soil and bedrock may occupy over half of the site.

Community 1.2
American Bistort and Piper's Woodrush

Structure: sparse forb and graminoid meadow This community is found in the aftermath of severe, vegetation-removing disturbance. Forbs and graminoids are the first to establish on site. This early community is dominated by American bistort (Polygonum bistortoides), Piper’s woodrush (Luzula piperi), showy sedge (Carex spectabilis), and Parry’s rush (Juncus parryi).

Pathway 1.1A
Community 1.1 to 1.2

Severe disturbance such as avalanche, landslide, or fire that removes most vegetation from the site.

Pathway 1.2A
Community 1.2 to 1.1

Time without disturbance.

Additional community tables

Supporting information

Other references

Breemen, Nico van. “How Sphagnum Bogs down Other Plants.” Trends in Ecology & Evolution 10, no. 7 (July 1, 1995): 270–75. 90007-1.

Dwire, K. and Kauffman, J. 2003. Fire and Riparian Ecosystems in Landscapes in the Western United States. Forest Ecology and Management, Vol. 178 pg. 61-74.

Franklin, Jerry F.; Cromack, Kermit, Jr.; Denison, William; [and others]. 1981. Ecological characteristics of old-growth Douglas-fir forests. Gen. Tech. Rep. PNW-118. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 48 p. [7551]

Gavin, D., Brubaker, L. (2015). The Modern Landscape of the Olympic Peninsula. In: Late Pleistocene and Holocene Environmental Change on the Olympic Peninsula, Washington. Ecological Studies, vol 222. Springer, Cham. https://doi.org/10.1007/978-3-319-11014-1_1

Geertsema, Marten & Pojar, James. (2007). Influence of landslides on biophysical diversity — A perspective from British Columbia. Geomorphology. 89. 55-69. 10.1016/j.geomorph.2006.07.019.

Goheen, E.M. and Willhite, E.A. 2006. Field Guide to Common Diseases and Inspect Pests of Oregon and Washington Conifers. Portland, Oregon: USDA Forest Service, Pacific Northwest Region R6-NR-FID-PR-01-06.

Hanley, D.P and D.M. Baumgartner. 2002. Forest Ecology in Washington. Washington State University Extension Publishing. Technical Report EB 1943.

Hanson, E.J., D.L. Azuma and B.A. Hiserote. 2002. Site Index Equations and Mean Annual Increment Equations for Pacific Northwest Research Station Forest Inventory and Analysis Inventories, 1985-2001. USDA Forest Service Pacific Northwest Research Station, Research Note PNW-RN-533.

Hemstrom, M., Franklin, J. 1982. Fire and Other Disturbances of the Forests in Mount Rainier National Park. Quaternary Research, Vol 18 pp 32-61.

James K. Agee and Mark H. Huff. 1987. Fuel succession in a western hemlock/Douglas-fir forest. Canadian Journal of Forest Research. 17(7): 697-704. https://doi.org/10.1139/x87-112

Nielsen, E. M., R. L. Brunner, C. Copass and L. K. Wise, 2021. Olympic National Park map class descriptions. National Park Service, Fort Collins.

Pojar J., and MacKinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine, Vancouver, British Columbia. 528 pages.

PRISM Climate Group, Oregon State University, http://prism.orgeonstate.edu, visited October 2023.

Reed Wendel, Darlene Zabowskl "Fire History within the Lower Elwha River Watershed, Olympic National Park, Washington," Northwest Science, 84(1), 88-97, (1 January 2010)

Rochefort, R.M. and Peterson, D.L. 1996. Temporal and Spatial Distribution of Trees in Subalpine Meadows of Mount Rainier National Park. Arctic and Alpine Research, Vol. 28, No. 1 pp 52-59.

Seastedt, T.R., Adams, G.A. 2001. Effects of Mobile Tree Islands on Alpine Tundra Soils. Ecology, Vol 82 pp 8-17.

Smith, K., G. Kuhn, and L. Townsend. 2008. Culmination of Mean Annual Increment for Indicator Tree Species in the State of Washington. USDA-NRCS Technical Note Forestry-9.

United States Department of Agriculture, Forest Service, 2015. Silvics Manual Vol 1. http://na.fs.fed.us/spfo/pubs/silvics_manual/Volume_1/vol1_Table_of_contents.htm, visited December 2015.

United States Department of Agriculture, Natural Resources Conservation Service, and United States Department of the Interior, National Park Service. 2014. Ecological Site Descriptions for North Cascades National Park Complex, Washington.

United States Department of Agriculture, Natural Resources Conservation Service, and United States Department of the Interior, National Park Service. Ecological Site Descriptions for Mount Rainier National Park, Washington.

Van Pelt, R. 2007. Identifying Mature and Old Forests in Western Washington. Washington State Department of Natural Resources, Olympia, WA. 104 p

Washington Department of Natural Resources, Natural Heritage Program. 2015. Ecological Systems of Washington State. A Guide to Identification.

Wood, David, and Moral, Roger del. “Mechanisms of Early Primary Succession in Subalpine Habitats on Mount St. Helens.” Ecology 68, no. 4 (1987).

Zhao, Yunpeng, Chengzhu Liu, Simin Wang, Yiyun Wang, Xiaoqing Liu, Wanqing Luo, and Xiaojuan Feng. “‘Triple Locks’ on Soil Organic Carbon Exerted by Sphagnum Acid in Wetlands.” Geochimica et Cosmochimica Acta 315 (December 2021): 24–37. https://doi.org/10.1016/j.gca.2021.09.028.

Contributors

Alec Haulotte
Erin Kreutz
Abigail Field
Max Ross
Erik Dahlke

Approval

Grant Petersen, 5/15/2025

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	05/16/2025
Approved by	Grant Petersen
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: