From a comparison of cambial cells and their derivatives between naturally occurring dwarf trees and normal ones, it was concluded that tracheids in the annual rings of dwarf trees are shorter, narrower and fewer than those of normal trees. The frequency of anticlinal division and loss of cambial initials is low during differentiation of xylem cells from cambial initials in dwarf pines. The length and intrusive growth of fusiform initials are slightly less than those of normal trees. Thus, it is concluded that the shortening of tracheids in dwarf trees is due to the fact that cambial initials are themselves shortened and that intrusive growth during differentiation of xylem mother cells has occurred.

In a comparison of cambial cells and their derivatives between naturally occurring dwarf and normal trees, vessel elements and fibers in the annual rings of dwarf trees were found to be shorter, narrower and fewer than those of normal trees. The frequency of anticlinal divisions and loss of cambial initials were low during the differentiation of xylem cells from cambial initials in dwarf trees. The length and intrusive growth of fusiform initials were slightly less than those of normal trees. Thus, it was concluded that the shortening of vessel elements and fibers in dwarf trees was due to the fact that cambial initials were themselves shortened and underwent inactive intrusive growth during differentiation of the xylem mother cells.

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.