Role of fire in seed germination of woody taxa in California chaparral.

Abstract

Germination behavior of 45 tree, shrub, subshrub, and liana taxa from fire-prone coastal sage scrub and chaparral was investigated. Nearly 1/3 of the species had seeds that germinated readily upon wetting, and germination was not further stimulated by any fire-related cue. Most coastal sage subshrubs germinate readily in the absence of fire-related stimuli and can thus colonize other forms of disturbance. For many of these species, germination was inhibited in the dark. This may result in a portion of the seed pool remaining dormant until fire since, in the case of several species, dark inhibition is overcome by charate. Chaparral shrubs and trees that germinate readily upon wetting seldom establish seedlings after fire. Seedling establishment and population expansion for such species is dependent upon extended fire-free periods. In contrast, woody species that fail to germinate without some fire-related cue have seedling establishment and potential population expansion restricted to postfire conditions. -from Author