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Abstract
Our knowledge of the long-term history of oaks is primarily based on biogeographical analysis of anomalous distribution patterns and paleobotanical macrofossil evidence. Neither of these provide a continuous record of change. In this paper, we present fossil pollen evidence which records significant changes in oak abundance over the last 10,000 years. Between 10,000-5,000 years ago, oaks in the Sierra Nevada increased at the upper altitudinal limit of their range. Since the mid-19th century, oaks at low elevations in the Coast Ranges have increased. We believe that the early increase represents an upward migration of oaks in response to climatic warming and changes in the fire regime, while the recent change reflects an increase in woodland density following a cessation of burning by Indians, a change in grazing pressure, or both.
Parent Publication
Citation
Byrne, Roger; Edlund, Eric; Mensing, Scott. 1991. Holocene Changes in the Distribution and Abundance of Oaks in California. In: Standiford, Richard B., tech. coord. 1991. Proceedings of the symposium on oak woodlands and hardwood rangeland management; October 31 - November 2, 1990; Davis, California. Gen. Tech. Rep. PSW-GTR-126. Berkeley, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 182-188
