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Home/Ecosystems/ California Foothill Mixed Oak Woodland

California Foothill Mixed Oak Woodland

EVT 7029Mediterranean California Mixed Oak Woodland
CES206.909GNRTreeHardwood
View on NatureServe Explorer
Summary
This ecological system is found throughout the Sierra Nevada and Coast Range foothills and lower montane elevations from 600-1600 m (1800-4850 feet) on steep, rocky slopes where snow and cold temperatures occur. Fire frequency and intensity drive composition of this system, with Quercus chrysolepis dominant with less frequent fires. With frequent annual burning (at lower elevations and on warmer sites), this system is an open to dense woodland of large oaks with well-developed grassy understories of native perennial bunchgrass. The predominant oaks with the higher frequency fires include Quercus kelloggii and Quercus garryana, with Quercus garryana var. garryana codominant in the central and northern Coast Ranges and Quercus garryana var. fruticosa often codominant in the northwestern Coast Ranges as well as portions of the Sierra Nevada. Quercus chrysolepis becomes dominant with less frequent fires (but in Oregon this species is not important and occurs in a different system, either Mediterranean California Mixed Evergreen Forest (CES206.919) or Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland (CES206.916)). The perennial bunchgrass component includes Festuca idahoensis, Festuca californica, Elymus glaucus, and Danthonia californica (close to the coast). A variety of native forbs also occur. Other characteristic species include Toxicodendron diversilobum, Juniperus occidentalis, and Ceanothus cuneatus. This system is similar to North Pacific Oak Woodland (CES204.852) but does not include a conifer component, and Quercus garryana is not the only oak.
Source: NatureServe Explorer
Vegetation
Fire frequency and intensity drive composition of this system, with Quercus chrysolepis dominant with less frequent fires. With frequent annual burning (at lower elevations and on warmer sites), this system is an open to dense woodland of large oaks with well-developed grassy understories of native perennial bunchgrass. The predominant oaks with the higher frequency fires include Quercus kelloggii and Quercus garryana, with Quercus garryana var. garryana codominant in the central and northern Coast Ranges and Quercus garryana var. fruticosa (= var. breweri) often codominant in the northwestern Coast Ranges as well as portions of the Sierra Nevada. Quercus chrysolepis becomes dominant with less frequent fires (but in Oregon this species is not important). The perennial bunchgrass component includes Festuca idahoensis, Festuca californica, Elymus glaucus, and Danthonia californica (close to the coast). A variety of native forbs also occur. Other characteristic species include Toxicodendron diversilobum, Juniperus occidentalis, and Ceanothus cuneatus.
Source: NatureServe Explorer
Environment
Climate is Mediterranean, where winter temperatures can be from near freezing to 10°C. Snow occurs in winter at higher elevations, but does not last all season. Annual precipitation is 100 cm (Barbour et al. 2007). Low-intensity fires are frequent (every 7-10 years). This system occurs in the foothills of the Coast Ranges and Sierra Nevada between 600-1600 m (1970-5250 feet) in elevation on steep rocky slopes.
Source: NatureServe Explorer
Dynamics
LANDFIRE model information: Fire Regime I, primarily short-interval (e.g., <10 years) surface fires. Surface fires every 3-10 years maintained an open savanna-like structure. Fires can be mixed-severity, especially when closed-canopy conditions or additional species such as conifers and shrubs are present. Native burning was a significant factor in fire frequency of this type, but return intervals may increase significantly with a little distance from native settlements and valley bottoms.
Source: NatureServe Explorer
Distribution
This system is found throughout the Sierra Nevada and Coast Range foothills and lower montane of California and Oregon at elevations from 600-1600 m (1800-4850 feet).
Source: NatureServe Explorer
Ecologically Associated Plant Species

Plant species that characterize this ecosystem type, organized by vegetation stratum. These are species ecologically associated with the ecosystem, not confirmed present in any specific area.

Tree canopy

Juniperus occidentalis, Quercus chrysolepis, Quercus garryana, Quercus garryana var. garryana, Quercus kelloggii, Quercus wislizeni

Shrub/sapling (tall & short)

Ceanothus cuneatus

Tall shrub/sapling

Quercus garryana var. breweri

Herb (field)

Danthonia californica, Elymus glaucus, Festuca californica, Festuca idahoensis, Toxicodendron diversilobum
Source: NatureServe Ecological System assessment
Ecologically Associated Animals (6)

Animal species ecologically associated with this ecosystem type based on NatureServe assessment. These are species whose habitat requirements overlap with this ecosystem, not confirmed present in any specific roadless area.

Mammals (3)

Common NameScientific NameG-Rank
Dusky-footed WoodratNeotoma fuscipesG5
Columbian White-tailed DeerOdocoileus virginianus leucurusG5T3Q
Western Gray SquirrelSciurus griseusG5

Birds (1)

Common NameScientific NameG-Rank
Oak TitmouseBaeolophus inornatusG4

Reptiles (1)

Common NameScientific NameG-Rank
Ring-necked SnakeDiadophis punctatusG5

Amphibians (1)

Common NameScientific NameG-Rank
EnsatinaEnsatina eschscholtziiG5
Source: NatureServe Ecological System assessment
At-Risk Species Associated with this Ecosystem (2)

Species with conservation concern that are ecologically associated with this ecosystem type. G-Rank indicates global conservation status: G1 (critically imperiled) through G5 (secure). ESA status indicates U.S. Endangered Species Act listing.

Common NameScientific NameG-RankESA Status
Columbian White-tailed DeerOdocoileus virginianus leucurusG5T3Q--
Brewer OakQuercus garryana var. breweriG5T3--
Source: NatureServe Ecological System assessment
Component Associations (8)

Plant community associations that occur within this ecological system. Associations are the finest level of the U.S. National Vegetation Classification (USNVC) and describe specific, repeating assemblages of plant species. Each association represents a distinct community type that may be found where this ecosystem occurs.

NameG-Rank
Quercus chrysolepis / Arctostaphylos patula ForestG3 NatureServe
Quercus chrysolepis / Arctostaphylos viscida ForestG4 NatureServe
Quercus chrysolepis / Dryopteris arguta ForestG3 NatureServe
Quercus chrysolepis - Umbellularia californica ForestG4 NatureServe
Quercus garryana - Quercus kelloggii / Toxicodendron diversilobum WoodlandG2 NatureServe
Quercus kelloggii / Arctostaphylos mewukka - Chamaebatia foliolosa ForestG3 NatureServe
Quercus kelloggii / Arctostaphylos patula ForestG3 NatureServe
Quercus kelloggii - Calocedrus decurrens ForestG4 NatureServe
State Conservation Ranks (2)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

StateS-Rank
CASNR
ORSNR
Roadless Areas (112)

Inventoried Roadless Areas where this ecosystem is present, identified from LANDFIRE 2024 Existing Vegetation Type spatial analysis. Coverage indicates the proportion of each area occupied by this ecosystem type.

California (107)

AreaForestCoverageHectares
Sycamore SpringsSierra National Forest36.4%1,475.64
North MountainStanislaus National Forest29.3%931.14
Ferguson RidgeSierra National Forest27.9%689.67
Oat Mtn.Sequoia National Forest24.0%1,186.83
Devil GulchSierra National Forest22.4%2,761.83
Black Mtn.Sequoia National Forest22.0%1,347.39
Polk SpringsLassen National Forest20.2%775.53
MonarchSierra National Forest18.9%53.1
Mill CreekSequoia National Forest17.7%1,976.04
Trumbull PeakStanislaus National Forest14.6%365.58
Tuolumne RiverStanislaus National Forest13.7%953.28
Kings RiverSierra National Forest13.6%2,917.98
San SevaineSan Bernardino National Forest13.6%377.46
Mill CreekLassen National Forest13.5%414.45
ChicoSequoia National Forest12.7%2,047.05
City CreekSan Bernardino National Forest12.7%512.64
AgnewSequoia National Forest12.2%472.41
CajonSan Bernardino National Forest11.7%356.49
Greenhorn CreekSequoia National Forest11.2%1,274.31
Dennison PeakSequoia National Forest10.8%275.13
UnderwoodSix Rivers National Forest10.7%284.49
IshiLassen National Forest10.6%931.05
Salt GulchShasta-Trinity National Forest10.5%275.76
MosesSequoia National Forest10.1%906.75
ChanchelullaShasta-Trinity National Forest9.1%144.63
Cucamonga BSan Bernardino National Forest8.9%427.41
Black ButteLos Padres National Forest8.8%181.98
Bell QuinbyShasta-Trinity National Forest7.8%362.79
ScodiesSequoia National Forest7.5%22.05
East GirardShasta-Trinity National Forest7.4%833.22
WoolstaffSequoia National Forest7.1%1,189.53
UnderwoodShasta-Trinity National Forest7.1%87.21
Chalk PeakLos Padres National Forest7.0%211.05
BlackKlamath National Forest6.9%183.42
RubiconEldorado National Forest6.7%132.93
Devils RockShasta-Trinity National Forest6.4%420.03
ChannellSequoia National Forest6.3%1,150.56
Black ButteMendocino National Forest6.0%376.92
Fisher Gulch BShasta-Trinity National Forest5.8%111.96
PortugueseKlamath National Forest5.6%429.66
RinconSequoia National Forest5.6%1,226.61
Lion RidgeSequoia National Forest5.2%111.6
Bear CanyonLos Padres National Forest5.1%297.27
Mill PeakSan Bernardino National Forest4.9%155.79
Thomes CreekMendocino National Forest4.9%327.51
Orleans Mtn.Klamath National Forest4.8%959.13
Kettle Mtn.Shasta-Trinity National Forest4.3%79.92
Cow CreekShasta-Trinity National Forest4.2%382.05
BackboneShasta-Trinity National Forest4.2%192.69
Reister CanyonMendocino National Forest4.1%98.1
Cucamonga CSan Bernardino National Forest4.0%66.69
China Springs BShasta-Trinity National Forest4.0%9.09
Arroyo SecoAngeles National Forest3.9%74.97
East BeegumShasta-Trinity National Forest3.8%131.04
PattisonShasta-Trinity National Forest3.8%447.84
North Fork Middle Fork American RiverTahoe National Forest3.8%171.72
Orleans Mtn. CSix Rivers National Forest3.3%207.18
ThatcherMendocino National Forest3.2%218.7
Strawberry PeakAngeles National Forest3.2%94.05
San Gabriel AddAngeles National Forest3.1%31.41
SnoozerKlamath National Forest3.0%287.46
West GirardShasta-Trinity National Forest3.0%449.37
BriscoeMendocino National Forest2.9%83.43
West ForkAngeles National Forest2.9%13.5
Bonanza KingShasta-Trinity National Forest2.8%187.56
Bear MountainLos Padres National Forest2.8%10.35
North Fork American RiverTahoe National Forest2.5%385.65
KelseyKlamath National Forest2.5%32.4
Cow CreekSix Rivers National Forest2.3%11.97
Cucamonga AAngeles National Forest2.3%11.7
Snow MountainMendocino National Forest2.3%134.73
WestforkAngeles National Forest2.2%38.61
Pyramid Peak BSan Bernardino National Forest2.0%59.22
RussianKlamath National Forest2.0%178.47
GrindstoneMendocino National Forest2.0%208.44
KangarooKlamath National Forest1.9%319.77
Machesna MountainLos Padres National Forest1.9%96.21
Sheep MountainAngeles National Forest1.9%163.89
Wells MountainShasta-Trinity National Forest1.9%44.82
South ForkShasta-Trinity National Forest1.6%110.97
Sill HillCleveland National Forest1.6%34.92
Cahuilla MountainSan Bernardino National Forest1.6%45.09
Horse Creek RidgeSan Bernardino National Forest1.6%57.69
San DimasAngeles National Forest1.5%43.65
Pilot CreekSix Rivers National Forest1.4%52.74
CuyamaLos Padres National Forest1.4%110.52
SoliderSix Rivers National Forest1.4%83.34
Dog CreekShasta-Trinity National Forest1.3%27.27
Crystal CreekSan Bernardino National Forest1.3%35.19
Duncan CanyonTahoe National Forest1.3%44.64
Salt CreekSix Rivers National Forest1.3%48.33
Fox MountainLos Padres National Forest1.3%264.33
Little French CShasta-Trinity National Forest1.2%54.27
GriderKlamath National Forest1.2%49.86
CalienteCleveland National Forest1.1%27.45
SiskiyouKlamath National Forest1.1%249.03
Mokelumne - Mt. BullionHumboldt-Toiyabe National Forest1.1%61.47
Garcia MountainLos Padres National Forest1.1%34.74
Lpoor CanyonLos Padres National Forest1.0%55.62
East YubaTahoe National Forest1.0%69.39
Deer MountainMendocino National Forest0.9%41.22
Raywood Flat BSan Bernardino National Forest0.8%38.07
West YubaTahoe National Forest0.7%44.55
Elk CreekMendocino National Forest0.7%63
AntimonyLos Padres National Forest0.6%102.42
South SierraInyo National Forest0.5%91.98
Sespe - FrazierLos Padres National Forest0.3%111.87

Nevada (1)

AreaForestCoverageHectares
Jobs Peak (NV)Humboldt-Toiyabe National Forest3.5%18.9

Oregon (4)

AreaForestCoverageHectares
Little GraybackRogue River National Forests1.6%51.03
KinneyRogue River National Forests1.2%36.18
North KalmiopsisSiskiyou National Forests0.8%298.8
South KalmiopsisSiskiyou National Forests0.5%195.93
Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.