Hurricane Katrina's carbon footprint on U.S. Gulf Coast forests

dead vegetation, and surface litter), soil, and shade for seasonally matched Landsat 5 images captured before and after the storm. The fractional change in NPV (∆NPV) from 2003 to 2006 provided a quantitative measure of the change in dead vegetation associated with Katrina. A subset for the Pearl River basin was stratified by DNPV to generate disturbance classes, and forest inventory plots were randomly established across the entire DNPV disturbance gradient (Fig. 1A). In each plot, tree mortality and damage, species composition, and biomass loss were quantified. A strong correlation between Landsat-derived DNPVand field-measured tree mortality and damage (fig. S1) enabled development of tree mortality and damagemaps from the Landsat imagery. Next, a second scaling function was generated by comparing Landsat- and MODIS-derived DNPV. With the high temporal frequency and large spatial dimension of MODIS imagery, the Landsat-MODIS scaling provided an assessment of hurricane disturbance across the entire impact region (Fig. 1B). To carry out this scaling, we generated distribution functions for stem density and tree biomass from our forest inventory plots and additional U.S. Forest Service data. A Monte Carlo model was devel