Natural Resources
Conservation Service
Ecological site R010XB029OR
JD Claypan 9-12 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 low sagebrush (Artemisia arbuscula) and bluebunch wheatgrass (Pseudoroegneria spicata). Abiotically, this site is characterized by soils typically with bedrock or claypans at shallow depths encouraging the growth of low sagebrush. The soil climate is Mesic near Frigid/Aridic. Historically, plant community dynamics were driven primarily by disturbances such as localized fire and drought. Presently, reference conditions are less common and current dynamics are influenced by the spread of invasive species, proliferation of western juniper (Juniperus occidentalis), livestock grazing pressures and fire suppression.
Associated sites
R010XC021OR |
SR Clayey 9-12 PZ Adjacent sites with clayey subsoils not heavy enough to restrict root penetration |
---|---|
R010XB022OR |
JD Clayey 9-12 PZ Adjacent sites with clayey subsoils not heavy enough to restrict root penetration |
Similar sites
R010XB080OR |
JD Claypan 12-16 PZ higher production, higher precipitation |
---|---|
R010XC038OR |
SR Very Shallow 9-12 PZ very shallow soils |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Artemisia arbuscula |
Herbaceous |
(1) Pseudoroegneria spicata ssp. spicata |
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Ecosystem states
States 2 and 5 (additional transitions)
T1A | - | Introduction of non-native plant species |
---|---|---|
T2A | - | Grazing management favoring shrubs and/or severe drought will reduce the perennial bunchgrasses in the understory. |
T2B | - | Catastrophic fire and/or soil disturbing treatments such as drill seeding, roller chopper, Lawson aerator etc. Probability of success of seeding on this site is low. Inappropriate grazing management in the presence of non-native annual species, may be combined with higher than normal spring precipitation. |
T3A | - | Catastrophic fire, multiple fires, and/or soil disturbing treatments, Inappropriate grazing management in the presence of non-native species |
T3B | - | Time and lack of disturbance allows for maturation of the tree community. |
R5A | - | Mechanical treatment of trees coupled with seeding of desired species. |
R5B | - | Mechanical treatment of trees. |
T5A | - | Catastrophic fire |