The authors intended to examine the relationships between the soil type and the forest type of the Okutama mountainous region, the latter being classified according to the plant sociological point of view. The result may be summarized as follows. (1) The classification according to the soil and to the vegetation thereon corresponds well. i) Under the Tsugetum sieboldii forest lies the BB type soil, the pH and the calsium content of which is low. Under the Fagus crenata forest, the BD type soil is commonly found and the soil has relatively thicker A horizon and shown high pH and calcium content. ii) From the plant sociological point of view, Fagus crenata forest is devided into tow comunities, i. e. Styrax obassia-Fagus japonica and Viburnum furcatum. The former is furthermore devided into two under units, i. e. the typical and the Carpinus codata under unit. These delicate variation in the vegetation reflects the underlying soil type. Under the typical under unit, the representative BD type soil is found, whereas under the Carpinus codata under unit there lies the soil that can be classed with the BD type soil but is fairly akin to the BE soil type. (2) To correlate the soil type and the synthetic attribute of various properties of an individual soil, the method of the multi variate analysis is applied. Of the various properties of the soil, 6 propaties relativly easy to determine are treated with the principal component analysis. The results shows the effectiveness of this method. Namely, the distribution pattern of the principal components of the individual soils agreed with the soil type, and accordingly, to the type of vegetation fairly well. These features can be seen on the Fig. 4.
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