Natural Resources
Conservation Service
Ecological site F043CY607OR
Cool Moist Conifer Foothills and Mountains (PIPO-PSME/SYAL)
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)
Ponderosa pine/common snowberry - CPS524 (modal)
Ponderosa pine/elk sedge - CPG222
Ponderosa pine/pinegrass - CPG221
Douglas-fir/elk sedge - CDG111
Douglas-fir/mountain snowberry - CDS625
Plant Assoc. of Wallowa-Snake Province (R6 E 255-86)
Ponderosa pine/common snowberry - CPS522 (modal)
Douglas-fir/mountain snowberry - CDS623
Ponderosa pine/spiraea - CPS523
United States National Vegetation Classification (2008)
Alliance (A3446) Central Rocky Mountain Ponderosa Pine/Shrub Woodland and Association
USDA Forest Service Ecological Sub-region
M332 “Blue Mountains”.
LANDFIRE BpS model 0710531
Northern Rocky Mountain Ponderosa Pine Woodland and Savanna – Mesic
Natureserve Terrestrial Ecological System (2020)
Northern Rocky Mountain Ponderosa Pine Woodland and Savanna, CES306.030e
Ecological site concept
This site represents a commonly occurring ponderosa pine (Pinus ponderosa) site in the foothills of the Blue, Ochoco and Wallowa mountains of Oregon. The overstory is composed of ponderosa pine, which is occasionally codominant with Douglas-fir (Pseudostuga menziesii). The herbaceous layer is dominated by grasses such as elk sedge (Carex geyeri), pinegrass (Calamagrostis rubescens) and forbs such as strawberry (Fragaria spp.), and heartleaf arnica (Arnica cordifolia). Unlike ponderosa forests nearby on droughtier soils, this site often hosts a characteristic shrub component of snowberry (Symphoricarpus spp.), with minor amounts of other low shrubs including creeping Oregon grape (Berberis repens). Forested sites at higher elevations and with greater proportions of volcanic ash, experience higher soil moisture retention which facilitates understory regeneration of grand fir (Abies grandis) and greater composition and productivity of Douglas-fir. The soil moisture regime of this site is xeric and the soil temperature regime is frigid. Disturbance was historically influenced by a fire regime characterized by relatively frequent surface fires. Frequent fire, as well as bark beetles, was historically a critical element of the disturbance regime of this site, acting to thin crowded understories and allow fire resistant mature ponderosa and Douglas-fir trees to attain an open, savanna-like forest structure.
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
F043CY608OR |
Cool Dry Conifer Foothills and Mountains (PIPO/FEID-PSSPS) Occupying adjacent soils with somewhat shallower depth to a restrictive layer and droughty properties |
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F043CY605OR |
Cool Moist Conifer Mountains and Plateaus (PSME-PIPO/CARU) Occupying adjacent somewhat deeper soils with greater soil moisture retention |
Similar sites
F043CY608OR |
Cool Dry Conifer Foothills and Mountains (PIPO/FEID-PSSPS) Lower available water content, somewhat shallower soils, higher coarse fragment content, andic soil properties less common |
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F043CY605OR |
Cool Moist Conifer Mountains and Plateaus (PSME-PIPO/CARU) Somewhat deeper soils, cooler climate, fewer dry days (45-60) |
F043CY609OR |
Warm Dry Conifer Foothills and Mountains (PIPO-PSME/SYAL/CAGE) Occupying lower elevations |
Table 1. Dominant plant species
Tree |
(1) Pinus ponderosa |
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Shrub |
(1) Symphoricarpos albus |
Herbaceous |
Not specified |
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Ecosystem states
States 1 and 5 (additional transitions)
T1a | - | Long term fire exclusion (50-100+) years |
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T1b | - | Widespread catastrophic stand replacing fire event |
T1c | - | Introduced range grass or exotic grass invasion |
T1d | - | Site converted to annual cropland or pasture/hayland |
R2a | - | Restoration practices that reduce excessive fuel loads and reduce overstory crown bulk density |
T2a | - | Widespread catastrophic stand replacing fire event |
R3a | - | Conifer planting |
R4a | - | Practices that promote the reestablishment of native understory species |
R4a | - | Practices are applied which reduce or eliminate unwanted weeds and invasive species |
R5a | - | Practices that promote the reestablishment of native understory species |
T5a | - | Poor management or abandonment leads to weed invasion |