Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (741.0 KB bytes)

Title: The paleohistory of California oaks

Author: Mensing, Scott;

Date: 2015

Source: Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 35-47

Publication Series: General Technical Report (GTR)

   Note: This article is part of a larger document. View the larger document

Description: Oak woodlands are a fixture of California geography, yet as recently as 10,000 years ago oaks were only a minor element in the landscape. The first fossil evidence for California's oaks is in the early Miocene (~20 million years ago) when oaks were present across the west, intermixed with deciduous trees typical of eastern North America. As climate became drier, species dependent upon summer precipitation went locally extinct and oaks retreated west of the Sierra Nevada. During the Pleistocene (the last 2 million years) oak abundance declined during cool glacial periods and expanded during warm interglacials. After the last glacial maximum (~18,000 years ago), oaks expanded rapidly to become the dominant trees in the Coast Ranges, Sierra Nevada foothills, and Peninsular Ranges. During the Holocene (the last 10,000 years) oaks in the Sierra Nevada were most abundant during a warm dry period between 8000 and 6000 years ago. Native American use of fire to manipulate plants for food, basketry, tools, and other uses helped maintain oak woodlands and reduce expansion of conifers where these forest types overlapped. Fire suppression, initiated by the Spanish and reinforced during the American period has allowed oak woodland density to increase in some areas in the Coast Range, but has decreased oaks where pines are dominant. Extensive cutting of oaks has reduced their populations throughout much of the state.

Keywords: California, oak woodlands, paleoecology, Quercus, vegetation history

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.



Mensing, Scott. 2015. The paleohistory of California oaks. In: Standiford, Richard B.; Purcell, Kathryn L., tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 35-47.


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.