LATE QUATERNARY VEGETATION HISTORY OF WHITE-PASS, NORTHERN BRITISH-COLUMBIA, CANADA

Paleoecological investigations at two sites in the White Pass, Drizzle Pond, and Waterdevil Lake, provide a record of late-Quaternary vegeta tion change in this mountainous region of northern British Columbia. T he vegetational sequence at Waterdevil Lake (875 m a.s.l.) has four st ages: (1) shrub tundra with alder (Alnus crispa) and dwarf birches (Be tula glandulosa/nana) from 10.5 to 8.5 ka; (2) shrub tundra with alder and dwarf birches plus juniper (Juniperus communis) on drier microsit es from 8.5 to 5.2 ka; (3) spruce (Picea) woodland from 5.2 to 4.0 ka; and (4) open woodland with lodgepole pine (Pinus contorta) and subalp ine fir (Abies lasiocarpa) from 4 ka to the present. Alpine shrub tund ra has persisted around Drizzle Pond (910 m a.s.l.) throughout the Hol ocene and only varied slightly in composition. The fossil record demon strates that White Pass did not serve as a migration route for those m ajor tree and shrub species that occur on both the coastal and interio r sides of the pass. Because the highest elevations in the pass have a lways been in alpine tundra, it is unlikely that trees could have cros sed the divide. Although subalpine fir, spruce (probably white spruce) , lodgepole pine, mountain hemlock (Tsuga mertensiana), and alder occu rred within the White Pass during the Holocene, the timing of their ar rival there in comparison with arrival times on the coast and interior also indicates that the pass was not the route by which these species entered the interiors of British Columbia or the Yukon Territory.