Quantifying burn severity in a heterogeneous landscape: A comparison of the differenced Normalized Burn Ratio and the Relative differenced Normalized Burn Ratio in the Grand Canyon National Park, Arizon

Burn severity mapping methods, including the differenced Normalized Burn Ratio (dNBR) and the Relative differenced Normalized Burn Ratio (RdNBR) are debated in the scientific community. I evaluated both the dNBR and the RdNBR burn severity methods on 32 fires from 2000 to 2007 in the Grand Canyon National Park, Arizona. The Composite Burn Index (CBI), a ground based measure of burn severity was evaluated with dNBR and RdNBR. Linear and nonlinear regressions were run on all fires to determine which burn severity method had a better correlation with CBI. It was found that nonlinear regressions correlated best with CBI in dNBR and RdNBR forest and RdNBR in woodlands. Linear regressions correlated best with CBI in dNBR woodlands. I expected that the dNBR values would perform best in a homogenous forested landscape, while RdNBR would perform better in a heterogeneous landscape. This study found no evidence that dNBR or RdNBR worked better in the different landscapes. The different change detection products produced different regressions that correlated with CBI.