Natural Resources
Conservation Service
Ecological site R010XB058OR
JD Mahogany Rockland 12-16 PZ
Last updated: 12/13/2023
Accessed: 11/21/2024
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 ecological site supports a plant community dominated by curlleaf mountain mahogany (Cercocarpus ledifolius), antelope bitterbrush (Purshia tridentata) and bluebunch wheatgrass (Pseudoroegneria spicata). Idaho fescue (Festuca idahoensis) and Sandberg bluegrass (Poa secunda) are also common. Abiotically, this site is typified by occupying canyon side slopes and very shallow soils with significant stones or cobbles present. The soil climate is mesic to frigid near mesic/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.
Associated sites
R010XB051OR |
JD Shallow South 9-12 PZ South aspect, shallow soils |
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Similar sites
R010XB057OR |
JD Mahogany Rockland 9-12 PZ lower herbaceous production |
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Table 1. Dominant plant species
Tree |
Not specified |
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Shrub |
(1) Cercocarpus ledifolius |
Herbaceous |
(1) Pseudoroegneria spicata ssp. spicata |
Click on box and path labels to scroll to the respective text.
T1A | - | Time without fire, possibly combined with improperly managed grazing |
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T1B | - | Crown fire that removes overstory woody species, possibly combined with improperly managed grazing |
T2A | - | Fire, drought event or improperly managed grazing |
T2B | - | Fire, possibly combined with improperly managed grazing |
T3A | - | Catastrophic fire, possibly combined with improperly managed grazing |
State 1 submodel, plant communities
P1.1A | - | Fire |
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P1.1B | - | No fire, improper grazing |
P1.2A | - | No fire |
P1.2B | - | No fire, improper grazing |
P1.3A | - | Fire, prescribed grazing |
State 2 submodel, plant communities
P2.1A | - | Juniper Maturation |
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