Fire history in Douglas-fir and coast redwood forests at Point Reyes National Seashore, California

Historical variability in lire regimes and forest age structures is necessa ry reference information for management of vegetation and landscape pattern s in naturally managed ecosystems. In this study, we reconstructed fire his tory and forest age structure at Point Reyes National Seashore on the centr al California coast to document changes in forest conditions over the past ca. two centuries. Surface fin history was reconstructed from dendrochronol ogically-crossdated fire scarred trees in two stands of Douglas-fir (Pseudo tsuga menziesii var, menziesii) and one stand of coast redwood (Sequoia sem pervirens). Age structure in an approximately 2000 ha area of Douglas-fir f orest was examined for tree recruitment patterns. Reconstructed mean surfac e fire intervals and Weibull median probability intervals ranged from simil ar to 7 to similar to 13 years. Fires generally occurred late in the growin g season or after growth had ceased for a year. Spatial patterns of histori c fires and those reconstructed from the fire-scar record document often wi despread fires in the central Olema Valley. Likely many, if not most, of th e fires reconstructed from Point Reyes were ignited by humans given the lon g history of intensive use of this area, first by the Coast Miwok and later by European ranchers. Age structures of stands suggest that much of the Do uglas-fir overstory is multiaged with little evidence of stand-replacing fi n or other disturbance events. Ages of trees in Douglas-fir stands document increasing landscape coverage of Douglas-fir forest at Point Reyes and har dwood recruitment under older Douglas-fu canopies, and suggest that loss of surface fires is having cascading effects on landscape vegetation patterns , community relationships, and probably related ecosystem processes.