Wednesday, 19 November 2003: 2:00 PM
Mean Fire Return Intervals as Indicators of Change in Boreal Siberia
Amber J. Soja, University of Virginia, Charlottesville, VA; and P. W. Stackhouse Jr. and H. H. Shugart
Boreal regions are particularly significant because these are the regions that are predicted to experience some of the largest temperature increases from climate change. Additionally, this is where the largest reservoir of terrestrial carbon resides, which could be released with increased fire and feedback to the atmosphere. Under current climate change scenarios, fire season length and fire weather severity are expected to increase, particularly in Siberia. Because temperatures have already increased across Siberia in the last decades, it follows that the interval between fire occurrences should decrease. In this study, evidence of fire-induced, climate-related change is investigated in boreal Siberia by comparing calculated mean fire return intervals with published mean fire return intervals. Fire return intervals are expected to decrease, resulting in a forest mosaic that is younger and more deciduous.
Satellite-based data are used to estimate area burned, which is overlaid on an ecosystem map to calculate area burned in 58 ecoregions across Siberia. Area burned data from 1995 through 2002 are used to calculate average fire return intervals for each ecosystem, as well as an average boreal forest fire return interval. Results from this investigation show that satellite-based mean fire return intervals are a viable method for accessing potential change in Siberia. Compared with published estimates, the calculated mean fire return intervals fall both above and below published means, but typically within the range of published estimates. This provides supporting evidence for the validity of using calculated mean fire return intervals as a tool for accessing potential change in boreal Siberia. More importantly, the mean fire return intervals presented here provide a baseline value from which future spatial and temporal comparisons of fire-induced land cover change can be compared.