Woody vegetation and succession in the Garin woods, Hayward Hills, Alameda County, California

Floral composition, stand structure, and successional relationships were studied in a stand of broadleaf evergreen forest in the East San Francisco Bay Hills, Hayward, Alameda County, California. Data from this study furnishes the first detailed profile of the woody plant communities in the Hayward Hills and provides a model for comparisons with other East Bay woodlands. Three main vegetational types were identified and characterized: a lower, bay (Umbellularia californica) woodland/forest; an upper, oak (Quercus agrifolio) woodland; and a central, apparently transitional oak-bay woodland; each vegetation type is defined by a distinctive tree-shrub assemblage. The author found good evidence to support McBride's (1974) paradigm of East Bay plant succession, i.e., a general movement toward a bay-dominated community and away from an oak-dominated assemblage. On the study site tree-fall of dead madrone (Arbutus menziesii) has opened much of the canopy and may be affecting the rate of this successional pattern.