Using high-resolution multitemporal, multispectral data, the authors classified tamarisk defoliation in the Glen Canyon area in Arizona. The high spatial resolution classification provides key information to effectively inform restoration treatments regarding where and how much mechanical removal or controlled burning could be performed. Furthermore, the defoliated tamarisk classification can help understand the site-specific and spatially-variable relationship between tamarisk and the tamarisk beetle at this critical state when their interactions are still developing and currently unknown.