Abstract
In Hita district, keyaki (Zelkova serrata) is roughly divided into three strains such as Aka-Geyaki, Ao-Geyaki and Zaku Geyaki, and they are traded and utilized. The difference of the tissue constitution was investigated, especially of the vessel elements in the cross sections among them. The vessel element ratio of the Aka strain was significantly higher than that of the Ao strain (p<0.01), while the density of the former was significantly smaller than that of the latter (p<0.01). The width of annual ring of the Aka strain was relatively narrow and the fluctuation of it was small. From these facts, it will be concluded that the wood quality of the Aka strain is light and soft because the vessel element ratio of it is high and much pores are existent within it. For the Ao strain, on the other hand, the vessel element ratio is low, the wood fiber content is high, and they have small pores in the wood, therefore, the wood quality of Ao strain is relatively heavy and hard. The Zaku strain showed the intermediate properties of the Aka and the Ao strain, and it is characterized to have much pores in wood fibers. From these results, the distinction of wood quality of those keyaki strains which have been judged only experientially so far, was clarified based on the differences of their anatomical features.
