Based on comparative-geographical considerations, the writer classified mountain forest soils, formed on various parent materials and distributed in warm-temperate laurisilvae (RUBEL: 1930) regions of our country, as a sub-type belonging to the world-wide bioclimatic i. e. zonal "transition type", from Brown forest soils (zonal soils in humid cool-temperate forest regions) to humid subtropical zonal soils (Red soils and Yellow soils), and named them "Warm-temperate forest soils". GERASSIMOV (1959) regarded the above-mentioned "transition type" as an independent bioclimatic genetic soil type, and named the soils "Yellow-brown forest soils". But the writer, considering the geographical distributions of the soils in the world and the soil colour of "Warm-temperate forest soils", proposed to discard the GERASSIMOV'S name "Yellow-brown forest soils", and to call the worldwide soil type "Reddish-yellow-brown forest soils". Using the new name, "Warm-temperate forest soils" in Japan and GERASSIMOV'S (1958) "Yellow-brown forest soils" in the Sochi district in U.S.S.R. are both to be classfied as different sub-types of "Reddish-yellow-brown forest soils". The reason is that, both the soils develop on the same fundamental type of bioclimatic conditions and have the same fundamental type of general constitution of the profile, and that as each soil, however, has different natural vegetations and their climatic conditions are not the same (e. g. in the former the natural vegetations are evergreen broad leaved forests and the precipitation is much in summer, and in the latter the natural vegetations are warm-temperate deciduous broad leaved forests and the precipitation is rather much in winter, Cf. WATANABE, S.: 1964), we should consider that there is rather distinct difference concerning the soil properties themselves. The general constitution of the profile of Warm-temperate forest soils is the same as Brown forest soils in cool-temperate forest regions, Red soils and Yellow soils in subtropical forest regions, but we can hardly find an eluvial podzolic horizon (cf. AKASHI, I.: 1959). Warm-temperate forest soils are, comparing with the profile of Acid brown forest soils (sub-type distributed in cool-temperate forest regions of Japan. cf. ENDO, K.: 1963 a), light in colour and somewhat more reddish and yellowish, and thin in the accumulation of organic layer (A_0). The reddish tint of Warm-temperate forest soils remarkably faints in B and especially C horizon, comparing with so-called Red soils (a kind of Relict Soils; cf. OHMASA, M., KUROTORI, T., KIDACHI, M.: 1957, 1963 a, 1963 b) in the official forest soil survey of Japan. Warm-temperate forest soils consist principally of 5 main groups of species (OHMASA in 1951 named this unit-type "Soil type" in Japanese) divided by their morphological characteristics (especially such as from and disposal of organic matter, size and shape of structure) corresponding to the peculiarities of the water regime. They are Exceedingly dried warm-temperate forest soils (YBA-soils), Dry warm-temperate forest soils (YBB-soils), Weakly dried warm-temperate forest soils (YBC-soils), Moderately moist warm-temperate forest soils (YBD-soils), and Slightly moist warm-temperate forest soils (YBE-soils). The writer doesn't consider that it is suitable to name each group of species as dry, moist, etc., but in the official forest soil survey such names as called by their comparative moisture conditions are used since OHMASA (1951) named each group of species in Brown forest soils (abbreviations such as BA-soil etc. are more usually used). Therefore the writer also followed their way. S. HONDA'S (1912) warm-temperate forest regions were divided into warm-temperate laurisilvae regions and subtropical forest regions (from the Amami Island
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