Holocene vegetation and natural disturbance in the Engelmann Spruce – Subalpine Fir biogeoclimatic zone at Mount Kobau, British Columbia

The vegetation and natural disturbance history of the Mount Kobau area, in the Engelmann spruce (Picea engelmannii Parry ex Engelm.) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.) (ESSF) forest of southern British Columbia, was reconstructed using pollen, plant macrofossils, and microscopic charcoal. Late-glacial vegetation, occurring from about 11 000 14C years BP, consisted of an Artemisia steppe under a cold and dry climate. Rapid warming occurred at the start of the Holocene, approximately 10 000 to 9500 years BP, and grassland steppe vegetation prevailed. Moisture increased during the midHolocene, from approximately 7000 to 3800 years BP, and fires may have occurred more widely and burned more severely. Open lodgepole pine (Pinus contorta Dougl. ex Loud.) parkland occupied the mountain summit. Late-Holocene cooling at 4000 years BP resulted in the establishment of modern ESSF forest. The vegetation and inferred climate history confirm a broad three-stage (warm dry – moderate moist – cool moist) regional climatic pattern of the Holocene. Under future anticipated climate change, the high-elevation, dry ESSF forests in southern British Columbia may be replaced by grasslands.