New macrofossil evidence for early postglacial migration of jack pine (Pinus banksiana) in the James Bay region of northwestern Quebec. (From boreal forest to high arctic desert: a theme issue commemorating 50 years of research by the Centre for Northern Studies (CEN) in Eastern Canada)

摘要

In the James Bay region of northwestern Quebec, earlier pollen data suggests that regional expansion of jack pine occurred around 4500-4000 cal BP, a period for which the species' pollen curve shows a marked increase in pollen diagrams. New macrofossil data from charred dune paleosols in the Radisson area indicates that the species has been present in this region since at least 6300 cal BP, despite a representation of only about 1% in pollen assemblages. The postglacial migration of jack pine is an example of low-density migration. The first individuals were probably restricted to dry sites such as eolian deposits and river terraces, upon which more frequent fires had a greater impact.