This 22-year study examined the impact and dispersal of the hemlock woolly adelgid (HWA) and the elongate hemlock scale at 67 sites in southwest Virginia. A hemlock stand health index was based on percent foliage density, live crown ratio, live branches, live tips, new foliage, and live trees at each site. At the beginning of the study, hemlock health at all sites was good. After 22 years hemlock health had declined to a poor...