In view of soil bio-climate, the Japan South Alps or Akaishi Mountains is situated in the humid marine climate region of the northern subtropic zone. With an increase in altitude from Paleozoic hilly terrain along the Lake Hamana to the main ridges, a series of vertical zonality of soils was found, and summarized as below. 1. The foot region of the Japan South Alps, below 500 m in height, consists of subdued Paleozoic terrain. The climate is northern humid subtropic, and the region belongs to the colline zone (TAKEDA, 1957). Under evergreen broad-lieved forest of Castanopsis cuspidata SCHOTT var., Sieboldii NAK., Cyclobalanopsis, and under its regenerated forest of Pinus deusiflora SIEB. & Zuco., develop Red-yellow soils (KANNO, 1961) on Paleozoic slate and relict red weathering crust. Their genesis is characterized by kaolinization. The region is located in a transitional zone between the Brown forest soil region under the humid temperate climate and the Red soil region under the middle part of the humid subtropic climate. 2. The maturely dissected foreland region of the Japan South Alps, with the altitude of 1,000 m, belongs climatologically to the marine humid temperate and plant-geographically to the montane zone. Under broad-leaved forest of Fagus crenata BLUME, Quercus crispula BLUME, and Quercus serrata THUNB., and under artificial forest of Cryptomeria japonica D. DON and Chamaecyparis obtusa ENDL., are formed Mountain brown forest soils on Mesozoic and Tertiary slate rocks, the genetical character being influenced by siallitization. The soils are more severely leached than RAMMAN'S "Braunerde", so regarded to be the Base-unsaturated subtype of the Brown forest soils from the degree of leaching (FRIDLAND, 1953). A weak podzolization of this soil is found in the upper part of the montane zone. 3. North of the foreland region follows dissected mountains of high relief represented by the main ridges of Japan South Alps. Slopes of the mountains with the altitude of 1,500 m to 2,600 m lie within the sub-alpine zone of the humid subboreal climate. Under coniferous forest of Abies Veitchii LINDL. and Abies Mariesii MASTER, there are Podzolic mountain brown forest soils, or Podzolized subtype of the Brown forest soils (FRIDLAND, 1953) on Mesozoic slate. Partially Alpine iron humus podzols with a distinct bleached horizon, A_2, are also found. In the upper part of the sub-alpine zone approximate to the forest limit, Alpine humus soils are formed under herbaceous vegetation of Gramineae and Cyperaceae, among sparce trees of Betula Ermani CHAM. 4. The main ridges of Japan South Alps above the timber-line are included in the alpine zone of periglacial or subnival climate. Piuus pumila REGEL is dominant species in this zone, and alpine grass covers small areas. One can find Alpine podzols with a distinct bleached horizon, A_2 and a well developed illuvial horizon, B_2. The soils are very gravelly, and solum, in most cases, being thin. Within the alpine grassland, Alpine humus soils under herbaceous vegetation with shrubs are found. The soils have similar characters to those of the subalpine zone, except the tendency to weak podzolization. Since Alpine iron-humus podzols and the Alpine humus soils coexist in a mosaic pattern within the same zone without any regularity or zonality in Japan South Alps, the Alpine humus soils concerned should be distinguished from similar soils found in European and American alpine grassland zones where the Alpine humus soils can be clearly separated upwards from Alpine iron-humus. podzols.
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