東亞暖温帯森林に於ける土地因子の特性

抄録

According to the Japanese pedologists, the temperate region of Japanese Archipelago, both the warm- and the cool-, is comprized in the zone of brown forest-soil. Owing to the very humid climate, prevailing in East Asiatic islands, it is rule in the cool-temperate region that the surface horizon of the climax soil is acidic and often podosolized. The result of the vegetational survey performed by the present writers in Izu peninsula, where nearly all the climax-types of temperate East Asia are represented vertically., shows that the climax of the broad-leaved evergreens (Machilus-,
Shiia-, and Cyclobalanopsis-type forests) stand on soil, which has A-horizon of higher pH-value compared with the underlying B-horizons; while in the deciduousclimax (Fagus-type forest) the state is converse.
Now, it will be sure that the climate and the vegetation, separating the East Asiatic temperate zone into the warm- and the cool-, affect also on soil to have the opposing inclination of pH-value when the surface and the bottom horizons are
compared. Within the climax area of the broad-leaved evergreens in Izu Peninsula, three types of profile can be recognized. The I-type is the most widely spread and has the best differentiated profile, while the II- and the Ill-types are found locally and imperfectly differentiated. It is the elevated topography causing drieness of the habitat that prevent the soil development in this case. Here percolating water is retarded by the thick accumulated litter and also the underlying mycorhiza layer in the Ill-type, and the imperfect differentiation of profile and the lower pH-value as in the deciduous climax are the results.
The correlation between these soil-types and plant-communities, now of lesser rank bellow association, can be considered as showing that the morphological characteristics of soil determine the type of communities and the progression of plant-
succession.