Evaluating Landscape Metrics as Predictors of Area Burned by Wildfire and Monitoring Landscape Level Change in the Interior Douglas-Fir Zone in British Columbia Bronson, Spencer
The Interior Douglas-fir zone of British Columbia’s Cariboo Region evolved alongside wildfire through millennia of repeat exposure. Resulting from these interactions were fire adapted species and landscape configurations that supported low to moderate severity wildfires. Removing the dominant disturbance agent of these dry forest ecosystems through systematic fire suppression has resulted in unforeseen repercussions. Presently, forests of the Interior Douglas-fir zone hold the potential for higher severity wildfire posing an increased threat to human life. This project was conducted to evaluate landscape metrics as predictors of area burned within the Interior Douglas-fir zone of the Cariboo Region. Six landscape metrics pertaining to the composition and configuration of landscape patches were calculated within 2500 hectare sampling cells. Additional work was conducted to quantify changing landscape metrics between 1985 and 2016. Key to this report are annual land cover maps generated following the Virtual Land Cover Engine framework applied to Landsat-5 TM and Landsat-7 ETM+ imagery. Results indicate that none of the landscape metrics involved in this project are effective predictors of area burned. Trend analysis from 1985 to 2016 concluded that several landscape metrics exhibited significant monotonic trends. The number of patches, landscape shape index, and Shannon’s diversity index were found to be increasing while mean patch area, and proportion of like adjacency were found to be decreasing. Additionally, no significant change in the area burned was observed. These results suggest that another agent, likely timber harvesting and climate change, are driving trends in landscape metrics. Overall, landscapes are becoming more heterogeneous. This does not necessarily translate to decreasing wildfire severity or size.
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