In suburban agricultural area, woods called as ‘Heichirin’ have been maintained on the strong tie with agriculture and rural lifestyle, but today deforestation is occurring with changing agricultural structure and urbanization. This study analyses decreasing woods in Ami-town (Ibaraki Pref.) for 20 years and identifies factors influencing this phenomenon. Ami-town is a plain village and its land has increasingly become residential and industrial in recent years. Area of woods is diminished by about 170 hectare in the 20 years between 1970 and 1990. The diminishing rate is remarkably high especially in urbanization promotion area.
In order to analyse determinants of diminishing woods, first, the 42 settlements in Ami-town are classified into 4 groups according to their socio-economic conditions as of 1970; Groupl is an agricultural district, Group2 has a large residential area in early times, Group3 has a large industrial area in farmland, Group4 is a developed area.
Second, on the ground of the above classification, we analyse correlation between changein socio-economic condition and diminishing rate of total area of woods in each settlement. Then three changes in condition are pointed out; (1) Development in agricultural side in 1960's, (2) Conversion of woodsinto industrial park and increase in farmers with a side job, (3) Population growth since 1980.
Third, multiple regression analysis is used in order to find the factors in each forest unit's character. We examine positive and negative correlation between the vanished forest units and their characters. Mainly, factors such as designation of specific areas (urbanization promotion area), spatial mass (larger scale), road accessibility (nearer to the roads) and topographical condition (artificial landform) have positive correlation.
In conclusion, the main factors of decreasing woods are 1) Demands of land parallel with the shift in industrial conditions, 2) Spatial conditions of each forest unit covering designation of specific areas, topographical condition, and so on.
Thus in order to conserve woods, public support is necessary. In Group2 and 4, which have been urbanized earlier, public support to prevent conversion of woods into built-up area is needed. In groupl and 3, people own woods as property and are not willing to pay for the management. Public supports motivating woods management for the owners are needed.

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This paper aims to make clear the conditions of maintaining rural spaces, classifying rural spaces byanalyzing the changes of the situation of maintaining rural spaces. We surveyed with hearing, mapping, sketching, collecting materials at two villages in‘Yabu’town in Hyogo prefecture.
As a result, these following points are made clear:
(1) The level of maintaining condition of the area around cultivation fields, which are not abandoned, isgenerally going down. (2) There are some areas that they maintain cultivation fields but they stop maintain-ing their surrounding spaces. Such cases are shown next to the abandon cultivation fields. (3) Raising cowhas important roles in maintaining village spaces. For example, in 1955, farmer cut grasses for food ofcows, cows eat grasses by themselves and step on grasses, and now raising cows make demand of newland use in stead of rice fields. (4) The area that maintenance works were stopped is expanding firstly fromthe mountainous area to the flat area, secondly from the flat area farthest from houses to the residentialarea. These results are caused by the geographical condition, aging, farm product damage by beast inoutside mountainous area. (5) The maintenance works are mostly composed of cutting grasses. (6) Cooperativeworks have been decreasing and have been settled in individual works since 1955. Then, individual thoughtsand consciousness influence the situation of maintenance.

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When we divide a whole region into homogeneous subregions, cluster analysis is often used and each unit district is permitted to belong to only one subregion in the analysis method. However, according to the object of the division, there are cases that unit districts must be permitted to belong to plural subregions. If it is permitted, we can grasp the many-sided characteristics about similarity among unit districts. Then, in this paper, the author devised the method for dividing whole region into subregions in which unit districts are permitted to belong to plural subregions and applied it to the homogeneous division of the whole 98 municipalities in San-in region.
In order to realize such a division, the author adopted the following way:
First, the whole region is divided into homogeneous subregions in application with cluster analysis provided the condition that unit districts belonging to each cluster must satisfy conditions of their homogeneity with one another. If unit districts belonging to each subregion are necessary to be contiguous with one another, contiguity constraints are also provided to the duster analysis. In this paper, the author adopted subregions made up in the previous paper as those before unit districts belonging to other subregions are included.
Next, for each subregion, unit districts that are belonging to other subregions but satisfy the same conditions of the homogeneity if included to it are included one after another to it. Doing so, each subregion becomes to include more unit districts. As a result, unit districts belonging to plural subregions are generated. In the case to consider also the contiguity constraints, unit districts satisfuing not only the conditions of the homogeneity but also the contiguity constraints become the objects for the inclusion.
As a result, it has become clear that the subregions made up in application with the method show the many-sided characteristics about similarity among unit districts compared with the subregions made up in application with usual dividing methods, in which unit districts are not permitted to belong to plural subregions. Moreover, in the case to consider the contiguity constraints too, the method is also useful to make up intermediate subregions between two subregions.

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