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Factors Affecting Seedling Survivorship of Blue Oak (Quercus douglasii H. & A.) in Central California

Informally Refereed
Download (PDF 326 KB): https://research.fs.usda.gov/download/treesearch/28402.pdf

Abstract

Blue oak seedling mortality was studied in relation to vertebrate predators, initial acorn planting position, slope and aspect, and oak canopy cover at two sites in the Central Coast Ranges of California. Seedling survival rates (Psd) were related to treatment variables using logistic regression analysis. Analysis of 2842 seedlings for 3 years following establishment indicated that site, rodents and acorn planting position were important variables explaining seedling losses. Seedling mortality was six times higher in the savanna site than the north-slope forest apparently because of unusually heavy competition between oak seedlings and annual grasses. Rodents were significant mortality agents at both sites. Overall, mortality was high during the first 3 years after seedling establishment with most losses occurring in the first year. Height growth of seedlings at both sites was very low. High seedling mortality coupled with slow growth rates and concomitant browsing apparently make the transition from seedling to small tree a rare event in this region.

Parent Publication

Citation

Davis, Frank W.; Borchert, Mark; Harvey, L. E.; Michaelsen, Joel C. 1991. Factors Affecting Seedling Survivorship of Blue Oak (Quercus douglasii H. & A.) in Central 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. 81-86