[in Japanese]

View full abstract

In Japan the emigration from villages to cities has been very marked through the period of the rapid economic development since 1955 to 1973. During this period many villages experienced a very marked depopulation problem. In the depopulated areas relocation of settlements (shuraku) has been put into operation as a project of the countermeasures to remove people of the depopulated and remote settlements into the areas with better public facilities. Many of this project have been put into operation as a matter of policy by the Economic Planning Agency, the Ministry of Home Affairs, etc., and also by the village (mura) authorities.
In this study I intend to explain the facts and the problems of relocation of settlements by taking two villages, different in characters, as examples from the Shikoku mountains Kito-mura in Tokushima Prefecture and Hiyoshi-mura in Ehime Prefecture. The reloca-tion of settlements in Kito-mura was put into operation as a model case of reorganization of villages by the Economic Planning Agency in 1971 and 1972, while in Hiyoshi-mura, the village did it by itself in 1973 by the flotation of loan.
Kito-mura is located in the eastern part of the Shikoku mountains and one of the greatest forestry regions in western Japan. The forest there are possessed by the large landowners in and around the village, and most villagers have made their living by working in the forests of the landowners, for the villagers lost their common forests during the Meiji era. Five settlements, Nakauchi, Uinouchi, Gonda, Hiso, and Azegano, all small settlements in the mountains which have been deserted by moving out of many families, were asked to evacuate their settlements and move to a newly built settlement called, Asahi-danchi near the village office. The inhabitants who scarcely possessed their land willingly agreed with the relocation of settlements, but some of them dropped off from the project of relocation beccause of the lack of helping-each-other mind or uniting mind. The jobs of the mi-grants are the same as before, and many of them are engaged in forestry works in the remote mountains and living in workmen's temporary huts.
Hiyoshi-mura is located in the western part of Shikoku mountains and made a slow pro-gress in forestry works. The inhabitants have long helped each other through the medium of their large common forests. Setsuyasu-buraku was made an object of settlement reloca-tion. This settlement at the remote corner of the village had twenty-five houses in 1960 but only seven in 1973. Finally Setsuyasu-buraku ceased to exist by mass migration to danchi, a housing development, built near the village office. The inhabitants of Setsuyasu-buraku with the strong power of cooperation accepted the relocation of their settlement, but these new comers could not establish good relation with the old people and have not yet joined the existing social system there. The jobs of the migrants are the same as before, and many of them have been work in the forest near the deserted old settlement they used to live.
The following are the gains and losses by the relocation of the settlements in these two villages. The relocation has given the migrants some conveniences for social life and has lessened the burden of social services to the inhabitants for village authority. On the cont-rary, the relocation has brought a negative impact on their economic activities if there is no countermove for employment, and have deserted the land use of the former settlments because of the evacuation of inhabitants even if there is some countermove for employment. I think that the existence of some remote settlements is indispensable from the viewpoint of conservation and development of the resources in the remote mountains. Isn't it necessary to reconsider the relocation of such settlements from the national point of view ?

View full abstract

The Kanto Earthquake in 1923 triggered a widespread debris-avalanching on the slopes of the Tanzawa Mountains (Fig. 2), located about 50 km southwest of Tokyo, and since then small debris avalanches have frequently taken place there due to heavy rainfalls. For two small sample areas, A and B (Fig. 1), the scars of debris avalanche on the aerial photographs taken in 1946 and 1971 were plotted on maps of a scale of 1:5000 by a photo-grammetric method with Autograph A8 and A7 (Fig. 3 and Table 1).
The scars are classified into the following three types according to their origin. 1) “New scars” formed after 1946 can be recognized only on the photographs taken in 1971. 2) Scars recognized both on the photographs taken in 1946 and 1971 are called “continuously naked scars”. 3) Naked scars only on the photographs taken in 1946 are called “vege-tated scars”.
It is considered that the mountain slopes are eroded by such processes as catastrophic debris avalanches, continuous debris fall in the naked and vegetated scars, and soil erosion on vegetated slopes. If each temporal change in area of these scars and vegetated areas (Sa_i, Sb, Sc and Sd) is known, the volume (DV) eroded during the period from t₁ to t₂ can be calculated from the formula (1). But it is assumed that each erosion rate of various processes is constant with time as shown in Table 2.
1) The maximum and minimum volumes of erosion for one year (1970_??_1971) were estimated by formulas (2) and (3) on the assumption that all of new scars were formed by debris-avalanching in the year of and before 1970.
2) Many scars observed on 1946's photographs can not be recognized on 1971's, being covered by vegetation grown during 25 years. The decreasing rate (R) of the area of these scars is expressed by formula (4). If new scars formed after 1946 have also been covered with vegetation at the same rate as R, area of new scars in 1971 may be ex-pressed by the formula (5), provided that new debris avalanches occurred with the same area (Sa_i) at every accident. The eroded volumes during the period from 1946 to 1971 were obtained as shown Table 3, assuming that the debris-avalanching happened every year, every 3 years, every 5 years, every 10 years and once in 1959. If it happened every 5 years, the eroded volume in the area A is expressed as the volume of solid in Fig. 5. Judging from the record of daily rainfalls in Yokohama about 40km east of the surveyed area, it is considered to be the most probable among the above cases that torrential rainfalls have occurred at an interval of about five years and triggered the debris-avalanching during the period in the Tanzawa Mountains (Fig. 4).
The most preferable estimate of erosion rate per unit area in the surveyed areas is in the order of 10³m³/km² year. This rate seems to be consistent with the maximum value of the various estimates of denudation rates from the sedimentation rate in many reservoirs of Japan. Most of the scars in 1946, which are inferred to have occurred triggered by the earthquake in 1923, are extraordinarily larger in area than the recent scars. These large debris avalanches may have occurred at an interval of 100 years or more, but small debris avalanches have occurred every several years and, therefore, are considered to be one of the most continuous erosion processes together with soil erosion.
From the consideration mentioned above it is concluded that the amount of erosion by continuous erosion processes during long period are comparable in order with that by cata-strophic erosion processes such as debris avalanches of extraordinarily large scale. If the above-estimated erosion rate is applicable to erosion processes in geologic times, the moun-tains would be dissected several hundred meters in relative height during several hundred thousand years.

View full abstract

In the Osaka Plain, the Nara Basin, the Kyoto Basin, the Ise Plain and the Nobi Plain, cultivated hatake (fields other than rice-fields) called “Shima-Hata” are often found in the rice-fields which are based on the ancient “Jon-System”. The “Shima-Hata” is an island-like or micro-mesa like upland field in each piece of the rice-fields.
This paper is to make a historico-geographical research on the process of the changing rural landscape in Japan. The present writer investigated when the “Shima-Hata” land-scape was made and what were the conditions necessary for its appearance. As a result of the investigation, the following conclusions have been found.
(1) The first historical document in which the above-mentioned “Shima-Hata” can be clearly recognized appeared at the end of the 14th century. Before the 12th century, however, it is thought that the “Shima-Hata” landscape did not exist. In consequence it is presumed that the “Shima-Hata” landscape was made in the 13th century or the 14th century for the first time.
(2) In the ancient “Ritsuryo” period, cultivated hatake other than rice-fields could be owned privately, while the rice-fields were possessed by the State. Hatake were under-valuated in comparison with the rice-fields. In the Medieval Ages, however, difference in official evaluation between hatake and the rice-fields dissolved, and a higher value was attached to hatake according to the advance of intensive utilization. It is in these Medieval Ages that the socially and economically basic conditions for the making of the “Shima-Hata” landscape were fulfilled. Therefore, it is to be said that the “Shima-Hata” land-scape was closely connected with the intensive cultivation in and after the Medieval Ages. This conclusion is consistent with the above-stated (1).
(3) The process of making the “Shima-Hata” landscape that the present writer has mentioned in (1) and (2) is also proved by the survey of microgeomorphology and surface geology.
(4) There are two ways of making the “Shima-Hata”.
A. By digging rice-fields located at the middle of a natural levee in order to obtain well-irrigated rice-fields.
B. By piling up mud at one part of each rice-field on a flood plain.

View full abstract