Postglacial vegetation and fire history, eastern Klamath Mountains, California, USA

Abstract

Pollen and high-resolution charcoal data from Bluff Lake and Crater Lake, California, indicate simi lar changes in climate, vegetation and fire history during the last 15 500 years. Pollen data at Bluff Lake suggest that the vegetation between c. 15 500 and 13 100 cal. BP consisted of subalpine parkland with scattered Pinus and Abies. After 13 100 cal. BP a relatively closed forest of P. monticola, P. contorta and Abies developed, and fire-event frequency was low. The inferred climate then was cooler and wetter than present. Pinus and Quercus vaccinifolia dominated at both sites during the early Holocene, when conditions were warm and dry. As climate became wetter and cooler in the late Holocene, Abies spp. at both sites and Tsuga mertensi ana at Crater Lake increased in importance, displacing Pinus and Quercus. The two lake records have similar trends in fire history, with high event frequencies at c. 8400, 4000 and 1000 cal. BP and low values at c. 4800 cal. BP. The fire and vegetation history at both sites suggests a similar response to large-scale changes in climate during the Holocene.