Dense networks within a group help bridging networks between groups: interchange of people between mountainous and urban areas

People embedded in dense social networks are likely to trust and cooperate with other members of their group. However, these individuals are also likely to turn inward and harbor strong hostility toward groups outside their network. Thus, it is important to establish bridging networks between groups. However, the effect of dense networks within a group on bridging networks between groups remains unclear. To elucidate the relationships between dense and bridging networks within and between groups, this study interviewed residents of the village of Nishiawakura in a mountainous region of Okayama Prefecture, Japan. We asked participants about their networks within the village and with urban residents. We found that established residents who had lived in the village for a long time maintained dense networks within the village to preserve their forests. Recently, however, these dense networks have not worked efficiently in a consistent manner. Returners (i.e., those who had returned from urban areas) were not embedded in the dense networks within the village and their forests had not been well preserved. However, they were more eager to form bridging networks with urban residents, hoping that urban residents would manage the abandoned forests in the village. On the other hand, established residents were skeptical about the effect of urban-mountain communications on the village. In this context, the dense networks of the established residents might have inhibited the development of bridging networks between this population and urban residents. However, the staff of the Mokkun Company is now developing bridging networks between the two groups. These are possible, in part, because staff members acknowledge the importance of the dense networks within the village. Hence, dense networks within a group might also help in the establishment of bridging networks between groups under certain conditions.