SPIRAL GROWTH IN CUDRANIA-TRICUSPIDATA CAUSED BY LIANA ENTWINEMENT

The anatomy of Cudrania tricuspidata stemwood that grew spirally due t o 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 i ncrement declined markedly as the liana continued to develop, producin g abnormal growth in the tree stem. The wood of the liana-affected ste m showed distinct differences in both cell orientation and anatomical characteristics compared with normal wood. In the first three years af ter entwinement, the vessels became inclined to the stem axis. In late r growth all the axial cells contributed to spiral grain angles up to 30 degrees to the stem axis. Dimensions of vessels and fibres were als o found to be affected. Physiological aspects of severe liana entwinem ent on the wood anatomy of the host stem are discussed.