Historic climate-fire-vegetation interactions of the West versus East Kootenays: Implications of climate change and fire suppression

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Our research compares the Joseph-Gold Creek watersheds near Cranbrook in the East Kootenay district and the Five Mile-Lasca Creek watersheds in West Arm Provincial Park near Nelson in the West Kootenay district of southeastern British Columbia. Theoretical fire-vegetation models suggest the historic fire regimes differed considerably in the two districts. Our study tests the hypothesis that the combined effects of human land use, fire suppression and climate variation have homogenized the fire regimes in the two locations. Risk of severe fires is presently high in both locations, primarily due to fire exclusion in the drier forests of the East Kootenay study area and increasingly frequent droughts in the more mesic forests of the West Kootenay study area. We will use a multi-proxy paleoecological approach to examine and compare the history of climate, vegetation and fire at a range of temporal scales at two locations in the West and East Kootenay districts of southeastern British Columbia. Paleoecological studies of lake sediments will quantify changes in fire regimes and forest composition over periods of 1000 to 10,000 years. Dendroecological (tree-ring) analyses will address the mechanisms by which these changes occur by (a) reconstructing climate over the last 300 to 500 years, (b) quantifying historic fire frequency through analysis of fire scars, and (c) investigating the impacts of inter-annual to decadal climate variation on fire regimes.