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Natural Resources
Conservation Service
Ecological site R043AX968MT
Montane Stable Colluvial Slope Saskatoon serviceberry-common snowberry/Sitka alder/ Rocky mountain maple/thimbleberry/mountain brome-Geyer’s sedge
Last updated: 9/08/2023
Accessed: 08/16/2024
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): 043A–Northern Rocky Mountains
This MLRA is located in Montana (43 percent), Idaho (34 percent), and Washington (23 percent). It makes up about 31,435 square miles (81,460 square kilometers). It has no large cities or towns. It has many national forests, including the Okanogan, Colville, Kootenai, Lolo, Flathead, Coeur d’Alene, St. Joe, Clearwater, and Kaniksu National Forests.
This MLRA is in the Northern Rocky Mountains Province of the Rocky Mountain System. It is characterized by rugged, glaciated mountains; thrust- and block-faulted mountains; and hills and valleys. Steep-gradient rivers have cut deep canyons. Natural and manmade lakes are common.
The major Hydrologic Unit Areas (identified by four-digit numbers) that make up this MLRA are: Kootenai-Pend Oreille-Spokane (1701), 67 percent; Upper Columbia (1702), 18 percent; and Lower Snake (1706), 15 percent. Numerous rivers originate in or flow through this area, including, the Sanpoil, Columbia, Pend Oreille, Kootenai, St. Joe, Thompson, and Flathead Rivers.
This area is underlain primarily by stacked slabs of layered sedimentary or metasedimentary bedrock. The bedrock formations range from Precambrian to Cretaceous in age. The rocks consist of shale, sandstone, siltstone, limestone, argillite, quartzite, gneiss, schist, dolomite, basalt, and granite. The formations have been faulted and stacked into a series of imbricate slabs by regional tectonic activity. Pleistocene glaciers carved a rugged landscape that includes sculpted hills and narrow valleys filled with till and outwash. Continental glaciation over road the landscape in the northern half of the MLRA while glaciation in the southern half was confined to montane settings.
The average annual precipitation is 25 to 60 inches (635 to 1,525 millimeters) in most of this area, but it is as much as 113 inches (2,870 millimeters) in the mountains and is 10 to 15 inches (255 to 380 millimeters) in the western part of the area. Summers are dry. Most of the precipitation during fall, winter, and spring is snow. The average annual temperature is 32 to 51 degrees F (0 to 11 degrees C) in most of the area, decreasing with elevation. In most of the area, the freeze-free period averages 140 days and ranges from 65 to 215 days. It is longest in the low valleys of Washington, and it decreases in length with elevation. Freezing temperatures occur every month of the year on high mountains, and some peaks have a continuous cover of snow and ice.
The dominant soil orders in this MLRA are Andisols, Inceptisols, and Alfisols. Many of the soils are influenced by Mount Mazama ash deposits. The soils in the area have a frigid or cryic soil temperature regime; have an ustic, xeric, or udic soil moisture regime; and dominantly have mixed mineralogy. They are shallow to very deep, are very poorly drained to well drained, and have most of the soil texture classes. The soils at the lower elevations include Udivitrands, Vitrixerands and Haplustalfs. The soils at the higher elevations include Dystrocryepts, Eutrocryepts, Vitricryands , and Haplocryalfs. Cryorthents, Cryepts, and areas of rock outcrop are on ridges and peaks above timberline
This area is in the northern part of the Northern Rocky Mountains. Grand fir, Douglas-fir, western red cedar, western hemlock, western larch, lodgepole pine, subalpine fir, ponderosa pine, whitebark pine, and western white pine are the dominant overstory species, depending on precipitation, temperature, elevation, and landform aspect. The understory vegetation varies, also depending on climatic and landform factors. Some of the major wildlife species in this area are whitetailed deer, mule deer, elk, moose, black bear, grizzly bear, coyote, fox, and grouse. Fish, mostly in the trout and salmon families, are abundant in streams, rivers, and lakes.
More than one-half of this area is federally owned and administered by the U.S. Department of Agriculture, Forest Service. Much of the privately-owned land is controlled by large commercial timber companies. The forested areas are used for wildlife habitat, recreation, watershed, livestock grazing, and timber production. Meadows provide summer grazing for livestock and big game animals. Less than 3 percent of the area is cropland.
LRU notes
This ecological site resides in MLRA 43A in the Livingston-Lewis-Apgar Mountains which includes the bulk of Glacier National Park (GNP) and the lower western valley portions along the Flathead River. The landscape is mountains and landforms include glaciated mountains with associated features such as U-shaped valleys, mountain slopes, alpine ridges, cirques, valley floors and moraines. Glaciation of this area was in the form of alpine, icecaps and valley outlet glaciers. It also includes associated alluvium and outwash features. This area includes low valleys to tall mountains with elevation ranging 989-2,762 m (3,250-9,050 ft.). The climate is cold and wet with mean annual air temperature of 3 degrees Celsius (37 degrees F)., mean frost free days of 65 days and mean annual precipitation of 1295 mm (51 in.) and relative effective annual precipitation is 169 cm (66 in.). The soil temperature regime is cryic and the soil moisture regime is udic. The geology of this area is dominated by metasedimentary rocks of the Belt Supergroup (Grinnell argillite and Siyeh limestone) with minor Tertiary sediments. Soils are generally weakly developed on mountain slopes within U-shaped valleys. Parent materials are commonly of colluvium, till, and residuum from metasedimentary rocks. Limestone bedrock within this part of the Belt Supergroup is not highly calcareous and due to high precipitation received in this area most carbonates at mid and upper elevations have been leached from the soil profiles. Bedrock depth varies greatly with location, landform and slope position. Volcanic ash is often found in the soil surface with various degrees of mixing. Thicker volcanic ash can be found on more stable positions on mid and upper elevation slopes that are protected from wind erosion. Volcanic ash is not typically found in low elevation areas on stream and outwash terraces associated with streams and rivers. There are numerous large lakes including St. Mary, Bowman, Kintla, Lake Sherburne, Logging, Upper Waterton and numerous creeks (
Classification relationships
NPS Plant Community Name:
Amelanchier alnifolia/(mixed grass, forb) Shrubland CEGL005885)
Physiognomic Class Shrubland (III)
Physiognomic Subclass Deciduous shrubland (III.B.)
Physiognomic Group Cold-deciduous shrubland (III.B.2.)
Physiognomic Subgroup Natural/Semi-natural cold-deciduous shrubland (III.B.2.N.)
Formation Temperate cold-deciduous shrubland (III.B.2.N.a.)
Alliance Amelanchier alnifolia Shrubland Alliance (A.913)
Alliance (English name) Saskatoon Serviceberry Shrubland Alliance
Association Amelanchier alnifolia / (Mixed Grass, Forb) Shrubland
Association (English name) Saskatoon Serviceberry / (Mixed Grass, Forb) Shrubland
ECOLOGICAL SYSTEM(S): Rocky Mountain Gambel Oak-Mixed Montane Shrubland (CES306.818)
Northern Rocky Mountain Montane-Foothill Deciduous Shrubland (CES306.994)
Amelanchier alnifolia/Pseudoroegneria spicata-Bunchgrass Shrubland (CEGL001065)
Physiognomic Class Shrubland (III)
Physiognomic Subclass Deciduous shrubland (III.B.)
Physiognomic Group Cold-deciduous shrubland (III.B.2.)
Physiognomic Subgroup Natural/Semi-natural cold-deciduous shrubland (III.B.2.N.)
Formation Temperate cold-deciduous shrubland (III.B.2.N.a.)
Alliance Amelanchier alnifolia Shrubland Alliance (A.913)
Alliance (English name) Saskatoon Serviceberry Shrubland Alliance
Association Amelanchier alnifolia / Pseudoroegneria spicata - Bunchgrass Shrubland
Association (English name) Saskatoon Serviceberry / Bluebunch Wheatgrass - Bunchgrass Shrubland
ECOLOGICAL SYSTEM(S): Northwestern Great Plains Mixedgrass Prairie (CES303.674)
Northwestern Great Plains Shrubland (CES303.662)
Rocky Mountain Gambel Oak-Mixed Montane Shrubland (CES306.818)
Ecological site concept
This ecological site is found on steep slopes (35-60 percent), on back, foot and toeslope positions on glacial valley wall landforms at elevations ranging from 1,150-2,100 meters (3,775-6,900 feet). This site is defined by the stabilizing nature of the root system of the shrub species present and their resprouting capabilities after disturbance. The reference community is defined as a mixed composition of serviceberry, snowberry, Sitka alder, Rocky mountain maple and other shrub species. Woods rose and chokecherry appear in low to moderate cover values. The understory is diverse and can range from drier site species with Oregon creeping grape, Geyers sedge and bluebunch wheatgrass occurring frequently and in high cover to moister site species including thimbleberry and mountain brome. Though monocultures of one shrub do exist, i.e. Ceonothus after a severe fire, the core concept for this ecological site is a mix of shrubs at all canopy cover layers. This ecological site is found on steep slopes with vegetation cover ranging from impenetrable shrubs to open canopy of medium statured shrubs with lush understory of grass and forb species. The thick vegetative growth contributes to the dark surface horizon colors in these soils. Ash is not usually present in these soils or is not very pure in these sites due to continual mixing caused by disturbance. These are very deep and well drained soils from till or colluvium from metasedimentary rock parent material. There is a high volume of fragments (50 to 67 percent by volume) within the soil profile. The predominant texture in the surface is very gravelly sandy loam and the subsurface is sandy skeletal. There are no redoximorphic features in the soil and there is rarely an argillic or mollic layer. There is a thin organic layer, usually less than 5 cm thick. The soils are usually in the Typic Haplocryepts taxonomic subgroup, and diagnostic features include an ochric epipedon and a cambic horizon.
Associated sites
R043AX962MT |
Alpine Unstable Talus rocky ledge penstemon (Penstemon ellipticus) The 43A alpine unstable talus ecological site resides on extensive talus slopes on very steep to steep slopes with a surface dominated by large rock fragments or talus. The landforms are cirque headwalls, colluvial aprons and glacial valley walls. The 43A alpine unstable talus ecological site has soils that are deep, well to somewhat excessively drained and have abundant rock fragments throughout. These soils are generally classified in the Entisols or Inceptisols soil orders, indicating that they have virtually no soil development because they are on active positions of the landscape or have only weakly developed soil diagnostic characteristics. The 43A alpine unstable talus ecological site has a reference vegetation community of Rocky ledge penstemon (Penstemon ellipticus), buttecandle (Cryptantha celosioides), silverleaf phacelia (Phacelia hastata) and alpine leafybract aster (Symphyotrichum foliaceum). |
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F043AX951MT |
Lower Subalpine Cool Dry Coniferous subalpine fir- Engelmann spruce/ Sitka alder/ thinleaf huckleberry/ common beargrass The 43A Lower Subalpine Coniferous Cool Moderately Dry (ABLA/CLUN2-XETE) ecological site is found in cool, moderately dry mid-elevations that span the lower subalpine areas. It is found primarily on lateral moraine and glacial valley wall landforms, on back or footslope positions, at elevations ranging 1,000 to 2,100 meters (3,280-6,900 feet), on all aspects and on moderate to steep slopes ranging 10-35 percent.The 43A Lower Subalpine Coniferous Cool Moderately Dry, (ABLA/CLUN2-XETE) site has soils associated with this Ecological Site that are very deep and well drained. These soils have developed in glacial till or colluvium parent materials derived from metasedimentary rock that typically have varying amounts of influence of volcanic ash in the soil surface layers. The dominant taxonomic soil order associated with these soils is Inceptisols with Andic subgroups indicating that there is 18 to 37 centimeters (7-14.5 inches) of volcanic ash. The 43A Lower Subalpine Coniferous Cool Moderately Dry (ABLA/CLUN2-XETE) ecological site has a reference vegetation community with an overstory of subalpine fir and Engelmann spruce with an understory of Sitka alder, huckleberry, beargrass and queencup bead lily. |
F043AX952MT |
Lower Subalpine Cool Moist Coniferous subalpine fir-Engelmann spruce/Rocky Mountain maple-thinleaf huckleberry/thimbleberry The 43A Lower Subalpine Coniferous Cool Moist (ABLA/CLUN2-ARNU2) is found in cool, moister mid-elevations that span the lower subalpine to subalpine. This ecological site is found on back, foot and toeslope positions, on glacial valley wall and moraine landforms, on all slopes, at elevations ranging 1,000 to 2,100 meters (3,280-6,900 feet). The 43A Lower Subalpine Coniferous Cool Moist Ashy Very Deep, (ABLA/CLUN2-ARNU2) has soils associated with this Ecological Site that are very deep, well drained or somewhat excessively drained and have subsoils with abundant rock fragments. The parent material is volcanic ash over glacial till from metasedimentary rock. In Soil Taxonomy, these soils classify primarily as Inceptisols soil order and more specifically as the Andic Haplocryepts taxonomic subgroup. The 43A Lower Subalpine Coniferous Cool Moist (ABLA/CLUN2-ARNU2) has a reference vegetation community of Subalpine fir-Engelmann spruce overstory and an understory of Rocky Mountain maple, thinleaf huckleberry, thimbleberry, wild Sarsaparilla, threeleaf foamflower and queencup bead lily. |
Table 1. Dominant plant species
Tree |
Not specified |
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Shrub |
(1) Amelanchier alnifolia |
Herbaceous |
(1) Bromus marginatus |
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