Although Japan’s planted forest resources are mature, efficient timber production and reforest postharvest are hindered by the small-scale forest ownership and private forest owners’ (PFOs’) low willingness to engage in forest management. A New Scheme of Forest Management (NSFM) has been established under which Japan’s municipalities can aggregate forest management rights which PFOs with low future intentions for forest management. Therefore, this study explores the socioeconomic factors that determine PFOs’ future intentions for forest management and examines NSFM challenges. PFOs were surveyed via questionnaires in two regions of Miyazaki Prefecture with different forest ownership sizes. The results showed that forest size and the presence of successors affect PFOs’ future intention for forest management. In addition, PFOs with low future intentions were less aware of their forests, and their forests were the source of reforest abandonment. Although aggregating forest management rights of PFOs with low future intention by the municipalities may contribute to sustainable forest management, the increased workload on municipalities is a challenge. Overall, accessibility to sufficient decision-making information is a prerequisite for evaluating PFOs’ future intention to manage their forests.