California oak woodland is a plant community found throughout the California chaparral and woodlands ecoregion of California in the United States and northwestern Baja California in Mexico. Oak woodland is widespread at lower elevations in coastal California; in interior valleys of the Coast Ranges, Transverse Ranges and Peninsular Ranges; and in a ring around the California Central Valley grasslands. The dominant trees are oaks, interspersed with other broadleaf and coniferous trees, with an understory of grasses, herbs, geophytes, and California native plants. Oak savannas occur where the oaks are more widely spaced due a combination of lack of available moisture, and low-intensity frequent fires. The oak woodlands of Southern California and coastal Northern California are dominated by coast live oak (Quercus agrifolia), but also include valley oak (Q. lobata), California black oak (Q. kelloggii), canyon live oak (Q. chrysolepis), and other California oaks. The foothill oak woodlands around the Central Valley are dominated by blue oak (Q. douglasii) and gray pine (Pinus sabiniana). California oak-woodland communities Oregon oak woodland is found in Northern California's Klamath-Siskiyou, Northern Coast Ranges, and southern Cascade Range. These woodlands are composed primarily of Oregon oak (Q. garryana), interior live oak (Q. wislizeni), and coast live oak, together with California black oak, canyon live oak, blue oak, Pacific madrone (Arbutus menziesii), California bay (Umbellularia californica), incense cedar (Calocedrus decurrens), coast Douglas fir (Pseudotsuga menziesiivar. menziesii), Coulter Pine and ponderosa Pine (Pinus ponderosa). Blue oak woodland is found in the inner coast ranges and the Sierra Nevada foothills, surrounding the Central Valley. It forms "one of the largest ecosystems in California". Primary species are blue oak (Q. douglasii) and interior live oak (or on west facing slopes facing the exterior ranges, particularly in Contra Costa and Alameda counties, coast live oak takes interior live oak's place), together with valley oak, canyon live oak, California scrub oak (Q. berberidifolia), gray pine, California buckeye (Aesculus californica), and western redbud (Cercis occidentalis). Coast live oak woodland is widespread in northern and southern California, and is dominated by coast live oak (Q. agrifolia), together with California buckeye, Pacific madrone, California bay, and California walnut (Juglans californica). Interior live oak woodland is found in north and south mountain ranges of California. It is dominant by interior live oaks(Q. wislizeni), blue oaks, foothill pine and shrubs in common with blue oak woodland. Valley oak woodland is found in the interior valleys of northern,