RELATIONSHIP BETWEEN DISCONTINUOUS FERMAFROST AND VAGETATION IN ALASKA

Abstract

The purpose of this paper it to detect discontinuous permafrost in the subarctic taiga of Interior Alaska by using geophysical prospecting. Alaskan taiga is characterised by permafrost overlaid with an active layer. For shallow discontinuous permafrost mapping, we carriedout electorical resistivity sounding. The following results were obtained: beneath north-facing slopes, there is a continuous high electorical resistivity zone, the under boundary of which is almost flat through summer, and the thickness of which is between 10 and 20m. It follows from this that the high resistivity zone is almost equivalent to permafrost zone. Beneath south-facing slopes, two high resistivity zones are near surface and underground cavities at the depth of about 15m. It follows from these that the high resistivity zones are not equivalent to permafrost zones, these phenomena of near surface appear to depend on being dried through summer and on cavities of scree. And the permafrost and whose active layer influence the biology of the taiga. The second goal of this study was to describe the temporal variation of vegetation. The north-facing slopes have Black spruce-mosses woodland. The south-facing slopes have Aspen-birch forest, whose foot have Sphagnum mosses mire. The watershed have Dwarf shrubs.