Spread of Alnus and Picea in Estonia

Abstract

The spread of alder (Alnus glutinosa and A. incana) and spruce (Picea abies (L.) Karst.) in Estonia is reviewed on the basis of 43 radiocarbon dated pollen diagrams and 10 macrofossil records from lake and bog profiles. Alder immigrated 9200-7700 BP, expanded 9100-6800 BP, and reached its maximum values 8400-3600 BP. Timing of alder spread varies considerably with sites and regions. The first stands of spruce dating to 8000-7500 BP were recorded in southeastern Estonia. Spruce reached the northern coastal area at the end of the Atlantic with an average range rate of about 100 m yr-1. The first spruce maximum is intermittent between 4000 and 2800 BP; the second maximum, not expressed in all examined pollen diagrams, is commonly between 2000 and 1000 BP. The macroremains of Picea evidence that spruce grew locally 1000-2000 years earlier than revealed in pollen record.