Wildfires dynamic in the larch dominance zone

Abstract

A fire return intervals (FRI) for zone of larch dominance and "larch-mixed taiga" ecotone was studied. Extreme fire events were connected with summer air temperature deviations. Average FRI determined from stem fire scar dating was 82 ± 7 years for the zone of larch dominance, and 77 ± 20 for the "larch-mixed taiga" ecotone. For the zone of larch dominance FRI on north-east facing slopes was 86 ± 11 years, for south-west facing slopes at 61 ± 8 years, for flat terrain at 68 ± 14 years, and for bogs 139 ± 17 years. FRI decreased from 101 years in the 19th century to 65 years in the 20th century, for the zone of larch dominance, and from 97 years to 50 years for the "larch-mixed taiga" ecotone. A climate and anthropogenic impact on this phenomenon was analyzed. The decrease of FRI may interfere with climate-driven migration of competitor species into zone of larch dominance, affecting biodiversity at high latitudes. Copyright 2008 by the American Geophysical Union.