Palynological and Paleoclimatic Study of the Late Quaternary Displacements of the Boreal Forest-Tundra Ecotone in Keewatin and Mackenzie, N.W.T., Canada
INSTAAR Occasional Paper 15
1975, 87 pp. (cost: $5)
[From the Preface] The aim of this study was to discover the Holocene displacements of the Canadian boreal forest-tundra ecotone resulting from climatic changes. Previous work (Nichols, 1967a, 1967b) had used palynology and peat stratigraphy to extend the initial findings of ecotonal shifts reported by Bryson, Irving, and Larsen (1965). These two studies involved vegetation boundary shifts caused by mean Arctic Front displacement in summer. They related to events along approximately 100°W between 62°N and 65°N, but appeared to have wider applicability (Nichols, 1967b, 1972, 1974). This project extended the earlier studies along the ecotone to test the validity of the schematic models of ecotonal displacement and paleotemperature reconstructions (Nichols, 1967b).
The ecotonal shifts and the associated alterations in paleowind directions were also believed to transport varying amounts of boreal forest pollen into the tundra and two short tundra pollen profiles were analyzed using a modification of routine methods to learn whether exotic pollen influx in the tundra could identify tree line movements.
Six ecotonal pollen diagrams are presented here (in addition to two from the High Arctic) and added to published evidence, they exhibit a cohesive response to climatic changes along the entire length of the ecotone so far examined by me, approximately 1400 km.PDF (114 MB)