Although California black oak, tanoak, and Pacific madrone are the principal hardwood species in the forest zone of California and Oregon and are key components of many plant communities, their seed production, regeneration, and early growth requirements have received little study. Information is presented on seed production, storage, and germination, and on the density, survival, and growth of three types of hardwood reproduction: seedlings, seedling-sprouts, and root-crown sprouts. Many trials showed that establishing planted seedlings in conventional sunlit plantations is difficult. Although initial stocking levels were high, height growth was poor. Dieback and death were common. Application of fertilizer and water and concomitant foliar analysis and tests of xylem sap tension indicated that internal moisture levels were inadequate to sustain seedling height growth. Thus, manipulating seedling-sprouts and root-crown sprouts currently are the silviculturist’s best techniques for establishing new stands. On a good site, root-crown sprouts of California black oak and tanoak were 20 feet tall in 10 years and those of Pacific madrone were 22 feet tall in the same time span. However, more information is needed on overstory-understory relationships for promoting the growth of seedling-sprouts and more knowledge is needed on clump density and thinning regimes for root-crown sprouts.
McDonald, Philip M.; Tappeiner, John C., II. 2002. California s Hardwood Resource: Seeds, Seedlings, and Sprouts of Three Important Forest-Zone Species. Gen. Tech. Rep. PSW-GTR-185. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. 39 p.