It is generally said that Pinus densiflora and P. Thunbergii which are important species in Japan segregate their habitats, but some researchers oppose this theory.
The writer has been engaged in the research of their habitat segregation since 1965.
This paper treats of the distribution of pine in the areas around Matsue.
The results obtained are as follows :
1) It is possible to say that P. densiflora and P. Thunbergii segregate their habitats, but partially overlap each other, as shown by the 2×2 table (ad＜bc) and Cole's index (-0.264).
2) Ridges and upper parts of a hillside are inhabited mainly by P. densiflora. At a dry valley and lower parts of a hillside, both tree species appear equally.
3) Dry places are inhabited mainly by P. densiflora, but scarcely by P. Thunbergii. Both tree species are seen together at properly wet places.