Age Structure and Importance of Naturalized Paulownia tomentosa in a Central Virginia Streamside Forest

The empress tree, Paulownia tomentosa (Thunb.) Steud., is native to eastern Asia and naturalized in portions of the eastern United States. In a central Virginia streamside forest, P. tomentosa trees ranged from 6 to 30 years in age (mean age = 17.1 years). The age distribution of P. tomentosa was unimodal with a strong peak in the 18 and 20 year age classes, demonstrating a major recruitment pulse in the early 1970s correlated with the passage of Hurricane Camille (August 1969). Paulownia tomentosa had the lowest importance value (=15.1) among the four dominant forest trees of the study area (Liriodendron tulipifera = 30.1, Betula lenta = 28.5, Platanus occidentalis = 16.0). Diameter distributions for all major tree species, except P. tomentosa, followed a concave pattern, which is representative of increasing or self-maintaining populations. The diameter and age distributions for P. tomentosa were convex, which indicates episodic establishment. Unlike many exotic woody plants naturalized in forests of the eastern United States, P. tomentosa is noninvasive and functions much as it does in the mesophytic forests of eastern Asia, producing small, scattered populations that arise chiefly as a result of large-scale disturbance.