Introduction and cultivation of Chinese hemlock (Tsuga chinensis) and its resistance to hemlock woolly adelgid (Adelges tsugae)

Abstract

Chinese hemlock (Tsuga chinensis) is native to mountainous regions in eastern, central, and southwestern China. Interest in the species has recently increased because of its potential resistance to hemlock woolly adelgid (HWA) (Adelges tsugae), an introduced insect that has been killing eastern hemlock (T. canadensis) in the eastern portions of its range since the 1980s. Despite the fact that Chinese hemlock was introduced into cultivation in 1901, its environmental tolerances are still largely unknown. This study reports on the performance of Chinese hemlock seedlings planted within a native stand of eastern hemlock (T. canadensis) at the Arnold Arboretum in Boston, Massachusetts, U.S., that was heavily infested with HWA. In comparison with a control group of eastern hemlock, Chinese hemlock seedlings were completely resistant to HWA damage after 4 years of exposure. The results of our investigation indicate that T. chinensis is fully hardy in USDA zone 6 and is a suitable replacement for T. canadensis in landscape situations because of its rapid growth rate, tolerance of shade, and resistance to HWA. © 2004 International Society of Arboriculture.