CGRG Bibliography of Canadian Geomorphology
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Author : Franklin-Smith, L.; and Edwards, M.E.
Date : 2006.
Title : Holocene climate interactions with vegetation and fire in Alaska-Yukon.
Publication : HOLIVAR 2006: Natural Climate Variability and Global Warming. Open Science Meeting, June 12-15, 2006. University College of London, London, United Kingdom.
Issue :
Page(s) : T2-008.
Abstract
The circumpolar boreal forest covers large areas of the high northern latitudes, and is important for feedbacks between land surface and atmosphere. Large carbon stores, fires and a dynamic ecotone with tundra mean that altered disturbance regimes in the boreal system are likely to have major impacts on climate via feedback mechanisms affecting the surface energy budget and atmospheric chemistry. Using radiocarbon-dated sedimentary records with the temporal focus on two key vegetative (deciduous-spruce and spruce-pine) and climatic (cold and dry to moister) transitions, high resolution time series of charcoal-peak frequencies from lake sediments are used as a proxy of the local fire regime. Results for the deciduous-spruce transition indicate climate change as the primary driver for altered fire regime, via transitions in major vegetation types. However, the shift in fire regime across the pine transition is associated with the appearance of fossil stomata (ca. 6 ka B.P.) instead of the traditional pollen increase (between ca 3 – 1.5 ka B.P, site dependent). This evidence is in conflict with conventional theory, which places pine in the landscape only when pollen percentage exceeds a 20% threshold. This alters views on the timing of the pine invasion at our sites and the influence of climate, and the regional migration history
Bibliography of Canadian Geomorphology