Presence of Camptotheca in the Red River Delta (North Vietnam) during the Holocene Revealed by Palynological Studies

Abstract

Aims: Evaluation of the presence of the important medicinal tree genus Camptotheca in the Red River Delta (northern Vietnam) during the Holocene. Place and Duration of Study: Institute of Botany and Landscape Ecology (Greifswald University), between March 2003 and May 2006. Methodology: Pollen analyses were performed on various sediment cores from the Red River Delta in order to reconstruct vegetation history and landscape development during the Holocene. Radiocarbon dates of selected levels provide a chronologic framework for various vegetation phases. Results: Camptotheca occurred with certainty in the Red River Delta, i.e. outside its current distribution area, around 6500 and somewhat after 6150-5500 cal yr BP. It was probably present during the complete 7400-5300 and 1400-250 cal yr BP time-slices. Presence during other time slices is possible, but could not be confirmed. Conclusion: Camptotheca ecologically represented a specific phase in riparian forest development, where it followed on Carya, Pterocarya and Salix during stages when the forest was relatively open. This study is a first step in understanding the past natural ecology of Camptotheca, which may provide information useful for management of Camptotheca plantations for medicinal purposes.