The recognition that are among the mountainous regions in Shikoku the most underpo-pulated regions in Japan is a basis to understand varied socioeconomic phenomena in the regions. It must be noticed, however, that the degree of underpopulation is not the same in all parts of the regions and that the underpopulation does not always mean deterioration in various as-pects of the socioeconomic activity. The author intends to consider these aspects in the light of regional socioeconomic evolution and reorganization. The area along the main watershed of the Shikoku Mountains, where the burning culti-vation system had widely been adopted, has been regarded as one of the representative moun-tain village areas in Japan. The western part of this area which had been characterized by the spring burning cultivation system, formed the heart of the whole burning cultivation area, but it is now in process of reorganizing the burning system to forestry. The eastern part, which was characterized by the summer burning cultivation system, is now mostly a stretch of undeveloped backwoods except the national forests in Kochi-ken and the private ones in the Kito area in Tokushima-ken. This part is the most underpopulated area in Shikoku. Extensive land used as burning fields in the western part of the Shikoku Mountains has been converted into conifer planting land, resulting in a marked decrease in area of the en-demic Mitsumata (Edgeworthia papyrifera Sieb. et Zucc.). While the area of burning fields in the eastern part is becoming the center of the niitsumata growing. The Kochi-Tokushima border area around the middle reaches of the Yoshino River is now the major center of mitsumata cultivation. In the western part, as mentioned above, forestry is becoming a leading industry though remaining some area for mitsumata growing in the pref ectural border area along the Niyodo River. Forestry is flourishing in the prefectural border area around the upper reaches of the Yoshino River, while mitsumata is mostly grown using a dense cultivation method on ordinary cultivated land. In short, mitsumata growing has been confined to the permanent arable area in the mountains, while the land used as burning fields is being converted into forestry land. The techniques of aff orestation in forestry are highly advanced in the mountainous area of Kochi-ken. This is primarily due to the fact that the forestry associations, commissioned by private or public enterprises, are making efforts to coordinate local activities by forming labor squads or by stream lining business management. The underpopulated areas in mountainous Shikoku are under the way to socioeconomic reorganization through the development of forestry. In Honkawa-mura in the uppermost reaches of the Yoshino River, where are vast forests owned by the state or private companies, forestry development is very actively pushed forward due to the improvement of transportation. Highway 194 leading to Saijo-shi and a motorable forest road connecting with Matsuyama-shi have already been opened for traffic services. Gene-rally speaking, better transportation results in the rapid development of backwoods. Terakawa-buraku, located the innermost section of Honkawa-mura, had been up to a very recent time one of typical burning cultivation villages in this country. All the burning fields have disap-peared from the buraku, and the people are more or less dependent upon forestry for their livelihood. All the households in the buraku follow some side business or other, the upper-class people managing forestry on their own land while the lower-class people are hired by various occupations connected with forestry.