Natural Resources
Conservation Service
Ecological site R043CY809OR
Warm Foothills and Mountains (PSSPS-POSE)
Last updated: 9/08/2023
Accessed: 11/13/2024
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): 043C–Blue and Seven Devils Mountains
This MLRA covers the Blue and Seven Devils Mountains of Oregon, Washington and Idaho. The area is characterized by thrust and block-faulted mountains and deep canyons composed of sedimentary, metasedimentary, and volcanic rocks. Elevations range from 1,300 to 9,800 feet (395 to 2,990 meters). The climate is characterized by cold, wet winters and cool, dry summers. Annual precipitation, mostly in the form of snow, averages 12 to 43 inches (305 to 1,090 millimeters) yet ranges as high as 82 inches (2,085 millimeters) at upper elevations. Soil temperature regimes are predominately Frigid to Cryic and soil moisture regimes are predominately Xeric to Udic. Mollisols and Andisols are the dominant soil orders. Ecologically, forests dominate but shrub and grass communities may occur on south aspects and lower elevations as well as in alpine meadow environments. Forest composition follows moisture, temperature and elevational gradients and typically ranges from ponderosa pine and Douglas-fir plant associations at lower elevations, grand fir at middle elevations and subalpine fir and Engelman spruce at upper elevations. Historical fire regimes associated with these forest types range from frequent surface fires in ponderosa pine - Douglas Fir forest types to mixed and stand replacing fire regimes in grand fir and subalpine fir types. A large percentage of the MLRA is federally owned and managed by the U.S. Forest Service for multiple uses.
Classification relationships
Plant Assoc. of Blue and Ochoco Mountains (R6 E TP-036-92)
bluebunch wheatgrass-Sandberg bluegrass - GB41
Plant Assoc. of Wallowa-Snake Province (R6 E 255-86)
bluebunch wheatgrass-Sandberg bluegrass-narrowleaf skullcap- GB4112
bluebunch wheatgrass-Sandberg bluegrass (basalt) - GB4113
bluebunch wheatgrass-Sandberg bluegrass-shaggy fleabane - GB4115
USDA Forest Service Ecological Sub-region
M332 “Blue Mountains”
U.S. National Vegetation Classification Standard (NVCS)
Group: G273. Central Rocky Mountain Lower Montane, Foothill & Valley Grassland
Alliance: A3987. Festuca idahoensis - Pseudoroegneria spicata - Poa secunda Dry Grassland Alliance
Association(s):
Pseudoroegneria spicata - Poa secunda Grassland
Pseudoroegneria spicata - Poa secunda Lithosolic Grassland
Ecological site concept
This site occurs on hillslopes, mountain slopes, and ridgetops with shallow to deep soils over hard igneous extrusive geologies (generally basalt, but also includes andesite, rhyolite, tuff, etc.) Occasionally, this site may occur with metamorphic, metavolcanic or sedimentary geologies. In the reference state, the site is characterized by bluebunch wheatgrass (Pseudoroegneria spicata) and Sandberg bluegrass (Poa secunda). Production is limited by the low water holding capacity of the soil or lower precipitation. Precipitation comes in the form of snow and rain primarily in the winter and early spring. Historically, plant community dynamics were driven primarily by disturbances such as localized fire and drought.
This ecological site and associated plant communities cover a broad range of elevations, soil climate regimes and soil depth classes. Further investigation will be needed to separate differences between these groups.
This is a provisional ecological site that groups characteristics at a broad scale with little to no field verification and is subject to extensive review and revision before final approval. All data herein was developed using existing information and literature and should be considered provisional and contingent upon field validation prior to use in conservation planning.
Associated sites
R043CY807OR |
Scabland (PSSPS-POSE-DAUN) Occupying adjacent shallow and very shallow soils on scablands |
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R043CY810OR |
Open Canyon Slopes and Fans (PSSPS-SPCR) Warmer, lower elevation |
Similar sites
R043CY810OR |
Open Canyon Slopes and Fans (PSSPS-SPCR) Warmer, lower elevation |
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Table 1. Dominant plant species
Tree |
Not specified |
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Shrub |
Not specified |
Herbaceous |
(1) Pseudoroegneria spicata |
Click on box and path labels to scroll to the respective text.
T1A | - | Introduction of non-native species |
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T2A | - | Severe or continuous disturbance in the presence of non-native annual species, may be combined with higher than normal spring precipitation. |