十勝平野歴舟川流域に分布する,時代を異にする河岸段丘崖の斜面形態を計測し比較することによって,地質時代を通じて斜面はどのように発達してきたのかを明らかにしようとした.
斜面は上部凸斜面部,直線部,下部凹斜面部からなる。凸斜面部は最終氷期の周氷河気候下で活発であった土壌葡行によって形成されたものと推定される.直線部のプロセスは凸斜面部のプロセスほど気候変化の影響を受けなかった.直線部の傾斜は最近の10×10⁴年間継続的に減小してきている.
低い崖の場合には上部凸斜面が下部凹斜面と直接接合する.このような場合には最大傾斜角は崖の比高の影響を受ける.十分高い崖の場合には中間に本来の意味での直線部が存在する.この直線部の傾斜角は崖の比高の影響を受けない.いずれの場合でも崖は減傾斜後退する.直線斜面が平行後退するためには崖の基部で河川による側刻あるいは下刻が不可欠であろう.

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The author analysed the results of previous studies and her own investigations on the prevailing wind direction estimated by wind-shaped trees (Abies Mariesii, A. Veitchii) in the 16 mountainous regions in the subalpine zone in Central and Northern Honshu, Japan. She studied, at first, the relationship between local wind directions and the running directions of mountain ridges which are classified into N-S, NW-SE, NE-SW and W-E. She also compared the wind directions estimated by wind-shaped trees with the data obtained from the instrumental observations at the climatological station near by.
The results obtained are summarized as follows:
(1) The prevailing wind directions are different regionally in accordance with the directions of mountain ridges. (2) According to the cluster analysis on the combination of wind directions by each direction of mountain ridges in the 16 regions, we can recognize some difinite wind systems with similar characteristics. (3) The regional division was made by these results as shown in Pig. 4. (4) On the basis of the results mentioned above, three climatological regions can be recognized in Central and Northeastern Japan, i.e., (i) The region where the mountain climate of Japan Sea side type prevails (Mt. HachimantaiIwate, Mt. Zao, Mt. Azuma-Adatara-Pandai, Happo-one, Mt. Renge-Eboshi-Mitsudake, Mt. Hakusan, Mt. Kusatsu-shirane). (ii) The region where the mountain climate belonging to the Pacific side type prevails (Ozegahara-nanryo, Mt. tsumata-KumonodairaTaro, Mt. Norikura, Mt. Neko-Azuma, Mt. Kisokoma). (iii) The region where the mountain climates of both types are mixed (Mts. Oku-nikko, Mt. Shiomi-Arakawa, Mts. Okuchichibu. Mt. Yatsu, Mt. Oomine). (5) Roughly speaking, the wind direction distribution estimated by wind-shaped trees on the Japan Sea side of Honshu is similar to the NW flow type of the surface wind system over lowlands. On the other hand, the wind direction distribution estimated by wind-shaped trees on the Pacific side of Honshu is similar to the SW flow type. (6) In addition, the author discussed the results with a few related phenomena: The regional division by climates presented here coincides well with that of the Suzuki's (1962), which was based on the distribution of precipitation in winter. It is, therefore, clear that the wind conditions over the mountainous regions have close relations to precipitation under the influence of winter monsoon.
(7) Shimagare phenomena (stripes of needle trees standing dead on the mountain slopes in the subalpine zone) are distributed on the slopes facing south, southwest and southeast in the subalpine zone in Chubu, . Kanto and Kinki Districts of Honshu. It is noteworthy that all of these areas belong to the mountain climate type on the Pacific side of Japan.

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