Sensitivity of the Landsat enhanced wetness difference index (EWDI) to temporal resolution

We investigated the sensitivity of the Landsat enhanced wetness difference index (EWDI) to temporal resolution in detecting forest harvesting and silvicultural activities in the Fundy Model Forest in southern New Brunswick. The severity of disturbance was underestimated in the multiyear EWDI because of regrowth and natural variability. In certain instances the severity of disturbance was overestimated with an annual EWDI; for example, a herbicide application in a young stand could have an annual wetness difference approximately equal to that of a forest clearcut. In general, we found annual EWDI differences to be more accurate than multiyear differences in detecting change. The sensitivity of satellite image change detection techniques to temporal resolution must be considered when national or international protocols are developed to provide input to forest monitoring or carbon accounting efforts.