California oak woodland

• 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 menziesii var. 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, central and southern California, and is dominated by valley oak (Q. lobata) and coast live oak, together with gray pine and Coulter pine (Pinus coulteri). • Island oak woodland is found on the California Channel Islands, and is made up primarily of island oak (Q. tomentella) and coast live oak, together with canyon live oak, MacDonald scrub oak (Q. berberidifolia) hybridized with valley or other oaks), Catalina ironwood (Lyonothamnus floribundus), and bishop pine (Pinus muricata). • Engelmann oak woodland is found in a few locations in the northern Peninsular Ranges of Southern California, including the Santa Rosa Plateau and San Gabriel Mountains foothills. It consists mostly of Engelmann oak (Q. engelmannii) together with coast live oak. ==Examples of occurrence==

The headwaters area of Yulupa Creek in Annadel State Park is cited as one of the best examples of California oak woodlands. Much of this woodland is a relatively pristine ecosystem with considerable biodiversity. An unusual characteristic of this Annadel forest is the high content of undisturbed prehistoric bunch grass understory, testifying to the absence of historic grazing or other agriculture. The Morro Bay watershed, located in Central California, is an example of a coast live oak ecosystem. This sub-category of California oak woodland consists primarily of coast wild oak and are predominantly found in coastal regions, but can extend to foothill ecosystems. == Ecology of California oak woodlands ==

The composition and characteristics of California oak woodlands varies across the state, but are defined by three main oak species throughout coastal regions: coastal live oak, Englemann oak, and Oregon white oak. The concentration of each of these oak species correlates with the location of the woodland throughout California. In the Sierra Nevada range, oak woodland is found on western slopes at elevations of in the northern part of the range, in the central part, and in the southern part. Annual precipitation in the oak woodland range is , with little precipitation in the summer. Among these species, the California quail (Callipepla californicus), Beechey ground squirrels (Spermophilus beecheyi), Botta pocket gopher (Thomomys bottae mewa), Audubon cottontail (Sylvilagus audubonii vallicola), deer (Odocoileus spp), bobcat (Lynx rufus californicus), coyote (Canis latrans) and the Pacific rattlesnake (Crotalus viridis oreganus) can commonly be found in California oak woodlands. Natural vegetation create habitat corridors that connect the patches of habitat that host species. Habitat corridors provide protection and food for animals that migrate between patches such as deer, mountain lions, bobcats, or gray foxes. Snags are the standing wood that is left when trees die and are home to wood-eating insects that are food for animals such as birds. Snags provide temporary refuge for small birds, bats, swallows, salamanders, and lizards. Similarly, downed wood provide refuge for animals that require moist areas, such as amphibians, cover for nesting of multiple species of birds, and areas for dens for larger snags. ==Status and future of California oak woodlands==

Blue oak woodlands cover about of the state, and of this area about 79%, or , shows no evidence of past cutting of trees. Recent research by the University of Arkansas Tree-Ring Laboratory has studied several unlogged stands of blue oak woodlands, and suggests that the state may harbor over of such old growth forests. This would make California's oak woodlands some of the most extensive old growth forests left in the state. However, most oaks of full tree size are more than one hundred years old, and few saplings are ever produced, because cattle often tear the plants to pieces. This comprehensive survey includes oak woodland maps and inventory data for the ten oak types found in California. By evaluating this new information against current State of California economic growth projections, the location and extent of oak woodlands most at risk of development are identified. Management practices, such as grazing (or the lack thereof) can lower soil fertility and nutrient level. A study performed by the University of California, Davis found that the prominent presence of oak trees in California oak woodlands creates areas of soil that are optimal for new growth. The Bureau of Land Management partnered with the California Biodiversity Council to carry out the Agreement on Biological Diversity, started in 1991, to protect and expand the following oakland wood areas: King Range National Conservation Area, Cache Creek Management Area, Yuba River Watershed in Inimim Forest, Consumes River Preserve, and Fort Ord. The methods used to ensure a healthy future for the California oak woodlands include maintenance and restoration of old-growth forests, watershed management and improvement, protection of water quality, protection of wildlife species that have cultural and environmental value to the area, restoration of valley oaks, and the habitat maintenance of "special status botanical species" and select endangered species. Due to residential and commercial development, 64% of California counties reported a decrease of greater than 5% in oak woodland area. ==See also==

• Dallman, Peter R. (1998). ''Plant Life in the World's Mediterranean Climates.'' California Native Plant Society–University of California Press; Berkeley. • Gaman, Tom and Firman, Jeffrey (2006). Oaks 2040: The Status and Future of Oaks in California. Published by the California Oak Foundation, Oakland. • Pavlik, Bruce M., Pamela C. Muick, Sharon G. Johnson, and Marjorie Popper (1991). Oaks of California. Cachuma Press and the California Oak Foundation; Los Olivos, California. • Schoenherr, Allan A. (1992). A Natural History of California. University of California Press; Berkeley. ==External links==