Long and short diameters of cones of Akamatsu and Kuromatsu were measured from the flowering season of 1955 to the summer of next year, in the Experimentary Forest of Shimane Agr. Coll.
The result were as follows :
1. Development of long and short diameters of cones of Akamatsu and Kuromatsu represented.
S-curve. The maximum growth of cones at 1st year fell at about May 20 in Akamatsu and at about May 10 in Kuromatsu. At the next year it fell between early May and early June in both species.
2. It appeares that air temperature did not affect the growth of cones, and precipetation affected a little at the 1st year and moderately at the next year.
3. The large strobilus at the flowering time made the large cone at the maturing season.
The large cone bore the large seed.