湯湾岳山頂附近の天然林の群落構造について

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1. The object of this study is to clarify the structure of the natural forest just under the summit of Mt. Yuwan, Isl. Amamioshima, the Ryukyus. 2. The natural forests at the summit and near the ridges of Mt. Yuwan are mainly composed of shrubs such as Myrsine Seguinii, Syzygium buxifolium, Elaeocarpus japonicus etc. about 2 m. in height. The natural forests, just under the summit of Mt. Yuwan covering the western slope protected from the S., E. and N. wind, mainly consist of the species such as Symplocos confusa, Ternstroemia gymnanthera, Ilex Mutchagara etc. attaining about 7 m. in average height. Symplocos prunifolia and Schima superba var. liukiuensis are the highest trees attaining up to 10 m. in height in the stand. 3. Brief descriptions of the temperature at 650 m. above the sea level calculated by the method used at Meteorological Agency in Japan, and the rainfall measured from the data of Naze meteorological station are shown in Table 1-2,and the hythergraph is shown in Fig. 1. 4. By the close observations made on the three plots, four strata were recognized in each forest. 5. To effect the investigation, three quadrats of 10 m.×30 m., 10 m.×10 m. and 10 m.×20 m. were located in the forests faced in the direction of N.N.W., W.N.W. and W. respectively ; and three belt transects of 2 m.×30 m., 2 m.×10 m. and 2 m.×20 m. were chosen to be located in each quadrat respectively, and the diameters, at the breath height, of all individual trees (above 2 cm. in diameter) belonging to the first (from 10 m. to 5 m. in height) and the second (from 5 m. to 2 m. in height) layers were estimated by callipers. The object of settling the three belt transects was to obtain some information concerning the floristic composition, frequencies and cover degrees of all the species belonging to the shrub (from 2 m. to 0.3 m. in height) and herbaceous (under 0.3 m. in height) layers. The obtained numeral data in the first and second stratum were converted into per ha. and these data of three quadrats and belt transects were summarized, repectively, in a table showing the floristic structure on each stratum. 6. For the estimation of frequency and cover degree, the following scale was adopted. + One or two individuals on the sample plot. 1. Present in small number of the individuals and cover the area less than 1/4 of the sample plot. 2. Present in more individuals, while covering the area less than 1/4 of the sample plot. 3. Cover the 1/4-1/2 area of the sample plot. 4. Cover the 1/2-3/4 area of the sample plot. 5. Cover the 3/4-1 area of the sample plot. 7. From these surveys it turned out obvious that the natural forests just under the summit of Mt. Yuwan represent Symplocos confusa and Symplocos prunifolia associations. The structural characteristics of the respective stratum of this forest are shown in Table 3-6. The second stratum and shrub layer of this forest consist largely of Myrsine Seguinii, and Plagiogyria adnata appears abundantly in the herbaceous layer of the forest. 8. The spinney on or near the summit of Mt. Yuwan represents a mossy forest in which the trunks and branches of the trees are densely covered with mosses together with several epiphytes. The chief feature of this forest is characterized by the scantiness of Castanopsis Sieboldii which is usually dominant in the natural forests at the lower parts of Isl. Amamioshima.
鹿児島大学の論文
1966-12-26

著者

迫静男
Laboratory of Silviculture

湯湾岳山頂附近の天然林の群落構造について

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