Clonal growth in Ailanthus altissima on a natural site in West Virginia

The exotic tree Ailanthus altissima is usually confined to open sites. As an exception, Ailanthus established in a densely closed forest in West Virginia, which was analyzed with the aim to elucidate possible pathways of persistence in forest succession of this light-demanding pioneer species. Demographic analysis revealed a seedling mortality of 100 %. Instead, the understory is populated by clonal ramets, ranging from one to more than 19 yr of age, with a mean of 5 yr. Growth averages only 0.11 m/yr, and height is correlated with age. This clonal growth contrasts with the performance of Ailanthus on open sites. The possible ecological benefits of establishing a ramet bank in a resource-poor habitat are considered in terms of space occupation of a pioneer species.