1. The material used (needles of 0-80-year-old trees) was collected from various places South of Lake Shinji, Shimane-ken.
2. The number of resin canals of a needle varied from zero to 12.
3. There was a high correlation between the number of resin canals and the size of a needle.
4. The number of resin canals of a needle on a shoot varied with the position of the needle on it. The number was found to be largest in the neeles on the upper part, and gradually decreased toward the lower part.
5. The number of resin canals in the needles varied according to the site and age of an individual tree.
In the case of trees at the age of more than 13 years, the number of resin canals of the needle was always more in the upper part of the stem than in the lower part, but there was generally no difference in the young trees. (below about 9 years old.)
In the southern edge of a wood, the number of resin canals of a needle on a shoot was more on the southern side than on the northern of the tree.
In the lower part of the stem, the number of resin canals of a needle was found to be more in the needles of shoots at the top of branches than in those near the joints, and the direction of branches did not constitute the significant factor.
6. Only primary resin canals were generally found in the trees of within 5 years, their number being 2, and rarely 3 including a seeondary one.
The secondary resin canals increased in number as the tree was older till about 12 years old.
As to the 6-12-year-old trees, the older they are the greater the number of conals is.
As for more than 13-year old trees, the number was approaching to their definite number decided according to their individual conditions.