California oak woodland

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
California oak woodland on the east flank of Sonoma Mountain.

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[edit]

Status and future of California oak woodlands[edit]

Blue oak woodlands cover about 2,939,000 acres (11,890 km2) of the state, and of this area about 79%, or 2,322,000 acres (9,400 km2), shows no evidence of past cutting of trees.[3] 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 500,000 acres (2,000 km2) 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.[2]

The Oaks 2040 survey estimates that 750,000 acres (3,000 km2) of California oak woodlands are seriously threatened by 2040 as a burgeoning state population makes ever more use of the wildland.[4] 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.

Examples of occurrence[edit]

The headwaters area of Yulupa Creek in Annadel State Park is cited as one of the best examples of California oak woodlands.[5] 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.

See also[edit]


  1. ^ C. Michael Hogan (2008) Blue Oak: Quercus douglasii,, ed. N. Stromberg Archived 2012-02-28 at the Wayback Machine
  2. ^ a b Stahle, David. "Ancient Blue Oak Woodlands of California". University of Arkansas Tree-Ring Laboratory. Archived from the original on 2008-12-04. Retrieved 2008-11-10.
  3. ^ Christensen, Glenn A.; Campbell, Sally J.; Fried, Jeremy S. (2008). "California's forest resources, 2001–2005: five-year Forest Inventory and Analysis report". United States Forest Service, Pacific Northwest Research Station: 40–46. Gen. Tech. Rep. PNW-GTR-763. Cite journal requires |journal= (help)
  4. ^ Tom Gaman and Jeffrey Firman. Oaks 2040: The Status and Future of Oaks in California.
  5. ^ Annadel State Park facts Archived 1997-10-11 at the Wayback Machine

General bibliography[edit]

  • 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[edit]