Natural Resources
Conservation Service
Major Land Resource Area 118B
Major Land Resource Area
Accessed: 04/24/2026
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1
Select an ecological site
Select an ecological site using the list, keys, photos, briefcase, or quick search option located on this page. -
2
Explore the ecological site description
Next, learn more about the selected ecological site and its characteristic dynamics by browsing the ecological site description and exploring alternative state and transition model formats.
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Viewing 7 of 7
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i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
-
i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
-
i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
-
i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
-
i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
-
i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
-
i
Key Characteristics
- Not as above,
- Geology older (generally Mesozoic Era) or mixed ages associated with Sierra Nevada (beginning around Lake Oroville)
- Geology highly complex, interfingering of volcanic, sedimentary (metamorphozed), and some granitics. The break between MLRA 17 and MLRA 18 is more gradual than in the southern LRU's, lower foothill slopes gently to strongly sloping. (LRU I)
- Site not as above
- Site occurs on a hill or hillslope (various geologies)
- MAP is at least 18 inches
- MAP > 25 inches
- Not as above
- Site in thermic soil temperature regime
- Site not as above
- Site not as above
- Site not as above
- Site occurs on moderately deep soils on slopes generally < 30%- blue oak, foothill pine, annual grasses, moderate density of shrubs.
Ecological site map
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Zoom in to display soil survey map units for an area of interest, and zoom out to display MLRAs. Select a map unit polygon to view ecological sites correlated to that map unit. View a brief description of an ecological site by clicking on its name in the map popup. Soil survey correlations may not be accurate, and ecological site classification of a location should always be verified in the field. Each selection may require the transfer of several hundred KB of data.
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Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase (
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Ecological sites
Major Land Resource Areas
Ecological site photos
Tools
Filter by
interactive key
precipitation
frost free days
more..
clear all
Type
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Interactive key
Precipitation
Frost free days
Elevation
Slope
Landform
Parent material origin
Parent material kind
Soil texture
Site receives additional moisture from the surrounding landscape, soils formed in alluvium.
Site does not receive additional moisture from the surrounding landscape.
Occurs on flood plain, soil characterized by seasonal water table, subject to rare to occasional flooding.
Occurs on high terraces and paleoterraces that are rarely to occasionally flooded.
NX118B01Y004 – Rarely Flooded Terrace
NX118B01Y004 – Rarely Flooded Terrace
Soils are fluventic (do not have restrictive soil horizon within 25cm, and are characterized by an irregular decrease in organic-carbon).
NX118B01Y008 – Fluventic Flood Plain
NX118B01Y008 – Fluventic Flood Plain
Soil characterized by greater than 18 percent clay by weight in the particle size control section.
NX118B01Y006 – Wet Flood Plain
NX118B01Y006 – Wet Flood Plain
Site occurs on summits, shoulders, and side slopes of interfluves, hills and mountains. Soils derived from colluvium and residuum.
Greater than 50cm to root restrictive layer (soils are moderately deep, deep, or very deep).
Site occurs on gently to moderately sloping hills and high terraces and soils are sandy in the particle size control section or loamy fine sand or fine sand in the upper 50-100cm.
NX118B01Y007 – Sandy Hillslope
NX118B01Y007 – Sandy Hillslope
Less than 50cm to hard bedrock (soil are very shallow or shallow).
NX118B01Y001 – Shallow Loamy Upland
NX118B01Y001 – Shallow Loamy Upland
Soil characterized by 35 to 60 percent clay by weight in the particle size control section (fine or clayey).
NX118B01Y002 – Clayey Upland
NX118B01Y002 – Clayey Upland
Soil characterized by 18 to 35 percent clay by weight in the particle size control section (fine-loamy or loamy).
NX118B01Y003 – Loamy Upland
NX118B01Y003 – Loamy Upland
Long term average mean annual precipitation
- No filter
- 100 – 120cm (39 – 47in)
—
cm
Long term average frost free days
- No filter
- 190 – 210days
—
days
- No filter
- 0 – 200m (0 – 700ft)
- 200 – 400m (700 – 1300ft)
- 400 – 600m (1300 – 2000ft)
—
m
- No filter
- 0 – 3%
- 3 – 5%
- 5 – 10%
- 10 – 15%
—
%
- No filter
- Flood plain
- Hillslope
- Mountain slope
- Paleoterrace
- Stream terrace
- No filter
- Chert
- Sandstone and shale
- Sedimentary, unspecified
- No filter
- Alluvium
- Colluvium
- Eolian deposits
- Residuum
Soil surface texture
- No filter
- Clay loam
- Fine sand
- Fine sandy loam
- Loam
- Loamy fine sand
- Silt loam
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Ecological site keys
MLRA 118B PROVISIONAL ECOLOGICAL SITE (PES) KEY - Arkansas Valley and Ridges West
1-
Site receives additional moisture from the surrounding landscape, soils formed in alluvium.
A-
Occurs on flood plain, soil characterized by seasonal water table, subject to rare to occasional flooding.
1-
Soils are fluventic (do not have restrictive soil horizon within 25cm, and are characterized by an irregular decrease in organic-carbon).
... NX118B01Y008 – Fluventic Flood Plain
2-
Soil characterized by greater than 18 percent clay by weight in the particle size control section.
... NX118B01Y006 – Wet Flood Plain
B-
Occurs on high terraces and paleoterraces that are rarely to occasionally flooded.
... NX118B01Y004 – Rarely Flooded Terrace
2-
Site does not receive additional moisture from the surrounding landscape.
A-
Site occurs on summits, shoulders, and side slopes of interfluves, hills and mountains. Soils derived from colluvium and residuum.
1-
Less than 50cm to hard bedrock (soil are very shallow or shallow).
... NX118B01Y001 – Shallow Loamy Upland
B-
Greater than 50cm to root restrictive layer (soils are moderately deep, deep, or very deep).
1-
Soil characterized by 35 to 60 percent clay by weight in the particle size control section (fine or clayey).
... NX118B01Y002 – Clayey Upland
2-
Soil characterized by 18 to 35 percent clay by weight in the particle size control section (fine-loamy or loamy).
... NX118B01Y003 – Loamy Upland
C-
Site occurs on gently to moderately sloping hills and high terraces and soils are sandy in the particle size control section or loamy fine sand or fine sand in the upper 50-100cm.
... NX118B01Y007 – Sandy Hillslope
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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