Chaparral response to a prescribed fire in the Mount Hamilton Range, Santa Clara County, California.

Native chaparral flora showed a response to late fall prescribed burning similar to the expected effects of a summer or early fall wildfire but with some important differences. Shrub cover was temporarily reduced by burning, but Adenostoma fasciculatum reached preburn cover within three growing seasons. Non-sprouting shrubs recovered more slowly, and repeated prescribed fires would favor A. fasciculatum. Native fire-following herb response to this prescribed fire had similar cover to that expected following wildfire, but species diversity was lower than reported from wildfires. Chaparral ecosystems occupy a large area of California and are important for wildlife habitat, watershed, and human activity (FRRAP 1988). Chaparral periodically burns, which temporarily reduces the shrub canopy and encourages herb growth (Hanes 1 977). The natural fire cycle can conflict with human values, therefore land managers have long sought to manage fire occurrence in chaparral (Sampson 1944). Fire management practice since 1900 has changed from unrestricted burning to attempts at complete suppression, eventually culminating in the present policy of prescribed burning for vegetation management. The general effects of fire on chamise chaparral are well known and have been the subject of several notable research programs (Cooper 1922; Sampson 1944; Biswell et al. 1952; Christensen and Muller 1975; Keeley et al. 198 1) and extensive reviews (Hanes 1977; Keeley and Keeley 1988). The mature shrub canopy accumulates fuels, which become highly flammable in late summer and fall, beginning about ten years after burning. The accumulated fuel burns, usually within a few decades, removing woody vegetation. Within a few months after fire, sprouting shrubs begin regrowth and dormant seeds of fire-following herb and suffrutescent shrub seeds germinate. Herbs and suffrutescents dominate the chaparral for a few years until the regeneration of dominant shrubs completes the cycle. Although the general pattern of fire effects on chaparral is documented, the variability among several important chaparral communities and some species is not (Keeley and Keeley 1988). AddiMadrono, Vol. 38, No. 1, pp. 21-29, 1991 This content downloaded from 207.46.13.38 on Sat, 21 May 2016 04:54:46 UTC All use subject to http://about.jstor.org/terms