Geovisualization techniques were used to describe and assess vegetation changes from the invasive exotic, hemlock woolly adelgid (HWA, Adelges tsugae Annand), among eastern hemlock (Tsuga canadensis L.) forest communities in Great Smoky Mountains National Park. Satellite imagery, aerial images, GIS-vector databases, digital elevation models and GPS field data were used to create photorealistic renderings 3D, multi-scale perspective views and animations. Plot-level visualizations included 3D tree models and field data to reconstruct forest structure. Existing vegetation databases were used for depicting pre-infestation conditions and derive forest structure changes at the landscape and stand-levels. Recent USDA National Aerial Imaging Program (NAIP) imagery provided post-invasion information to update existing vegetation databases and describe dieback patterns at the landscape scale. Targeting visual acuity of human cognition, results of this work offer innovative methods for assessing and portraying to various audiences the implications of losing a foundation species in the southern Appalachian forests.