Natural Resources
Conservation Service
Ecological site R010XC080OR
SR Mahogany Mountain Loam 14-18 PZ
Last updated: 12/13/2023
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): 010X–Central Rocky and Blue Mountain Foothills
This MLRA is characterized by gently rolling to steep hills, plateaus, and low mountains at the foothills of the Blue Mountains in Oregon and the Central Rocky Mountains in Idaho. The geology of this area is highly varied and ranges from Holocene volcanics to Cretaceous sedimentary rocks. Mollisols are the dominant soil order and the soil climate is typified by mesic or frigid soil temperature regimes, and xeric or aridic soil moisture regimes. Elevation ranges from 1,300 to 6,600 feet (395 to 2,010 meters), increasing from west to east. The climate is characterized by dry summers and snow dominated winters with precipitation averaging 8 to 16 inches (205 to 405 millimeters) and increasing from west to east. These factors support plant communities with shrub-grass associations with considerable acreage of sagebrush grassland. Big sagebrush, bluebunch wheatgrass, and Idaho fescue are the dominant species. Stiff sagebrush, low sagebrush, and Sandberg bluegrass are often dominant on sites with shallow restrictive layers. Western juniper is one of the few common tree species and since European settlement has greatly expanded its extent in Oregon. Nearly half of the MLRA is federally owned and managed by the Bureau of Land Management. Most of the area is used for livestock grazing with areas accessible by irrigation often used for irrigated agriculture.
Ecological site concept
In reference condition, this site supports a plant community dominated by curlleaf mountain mahogany (Cercocarpus ledifolius), antelope bitterbrush (Purshia tridentata) and Idaho fescue (Festuca idahoensis). Ponderosa pine (Pinus ponderosa), mountain big sagebrush (Artemisia tridentata ssp. vaseyana), wax currant (Ribes cereum) and bluebunch wheatgrass (Pseudoroegneria spicata) are also prominent. Cover of ponderosa pine is less than 10 percent. This site is typified abiotically by moderately deep to deep, skeletal soils and areas of rock outcrop. The soil climate of this site is frigid and xeric. Historically, the ecological dynamics of this site were driven by infrequent fire and cycles of drought. Presently, reference conditions are less common and current dynamics are also influenced by the spread of invasive species, the expansion of western juniper (Juniperus occidentalis), livestock grazing pressures and fire suppression.
This is a provisional ecological site whose accelerated development from a draft site was undertaken 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
R010XC032OR |
SR Mountain 12-16 PZ SR Mountain 12-16 PZ |
---|---|
R010XC033OR |
SR Cool 12-16 PZ SR Cool 12-16 PZ |
R010XC059OR |
SR Mahogany Rockland 12+ PZ Mahogany Rockland 12 |
R010XC066OR |
SR Mountain North 12-16 PZ SR Mountain North 12-16 PZ |
R010XC082OR |
SR Dry Pine 14-16 PZ Dry Pine 14-16 |
R010XC037OR |
SR Mountain Shallow 12-16 PZ SR Mountain Shallow 12-16 PZ |
R010XC039OR |
SR Very Shallow 12-16 PZ SR Very Shallow 12-16 PZ |
R010XC047OR |
SR Mountain South 12-16 PZ SR South 12-16 PZ |
Similar sites
R010XC059OR |
SR Mahogany Rockland 12+ PZ Very shallow soils |
---|---|
R010XC082OR |
SR Dry Pine 14-16 PZ Mountain mahogany and areas of rock outcrop less common |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Cercocarpus ledifolius |
Herbaceous |
(1) Festuca idahoensis |
Click on box and path labels to scroll to the respective text.
Ecosystem states
T1A | - | Disruption of the fire return interval, extending time without fire which allows for conifer expansion, especially western juniper |
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T1B | - | Catastrophic fire in the presence of invasive annual grasses, |
T2B | - | Mechanical or chemical treatment of controlling brush or mechanical treatment of juniper along with treatment of non-native invasive species. Desired grasses and forbs may need to be seeded. |
T2A | - | Catastrophic fire in the presence of invasive annual grasses. |
State 1 submodel, plant communities
1.1A | - | Low severity fire |
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1.1B | - | Low severity fire, high severity fire, drought or inappropriate grazing. |
1.2A | - | Time without fire |
1.2B | - | high severity fire, drought or inappropriate grazing |
1.3A | - | Time without fire |
State 2 submodel, plant communities
2.1A | - | Time without fire |
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