Spiral Growth in Cudrania Tricuspidata Caused by Liana Entwinement

Abstract

The anatomy of Cudrania tricuspidata stemwood that grew spirally due to liana entwinement has been examined. In the first three years after entwinement by the liana (Pueraria thunbergiana) annual radial growth of the stemwood increased by 1.2 to 5.0 times . Thereafter the radial increment declined markedly as the liana continued to develop, producing abnormal growth in the tree stem. The wood of the liana-affected stem showed distinct differences in both cell orientation and anatomical characteristics compared with normal wood. In the first three year s after entwinement, the vessels became inclined to the stem axis. In later growth all the axial cells contributed to spiral grain angles up to 30° to the stem axis. Dimensions of vessels and fibres were also found to be affected. Physiological aspects of severe liana entwinement on the wood anatomy of the host stem are discussed.