**2. Materials and Methods**

First, the author consulted secondary literature and official statistics to determine the historical policy developments affecting *iriai* forests and the institutional arrangements of FPCs and ANAs.

Second, the author collected firsthand data from surveys through face-to-face interviews in the Fukuoka and Saga prefectures on Kyushu Island. For the Fukuoka prefecture, the author mailed a letter to all 55 FPCs registered in a database requesting an interview. The author received responses from 11 cases, which included 2 ANAs. For the Saga prefecture, the author purposefully selected 1 ANA; this was a case where former FPC members and residents were not the same and the number of residents in the neighborhood was far greater than the number of former FPC members. The author sought to observe what kinds of problems exist in such a situation. In total, the author obtained 9 FPC cases and 3 ANA cases; they are called FPCs A to I and ANAs A to C to preserve anonymity. The 3 ANAs included no cases of status change from the 9 FPCs—in other words, they were separate from each other. Topics surveyed included FPCs' or ANAs' basic information, recent management activities, and financial conditions. Data were collected in October 2018, February to May 2019, October 2020, and May 2021.

It should be noted that the present study is not based on random sampling methods. Regarding the Fukuoka prefecture, the author was able to obtain information from FPCs to which letters from the author were successfully delivered and who were willing to take interview surveys. The addresses of many FPCs provided in the database were wrong; consequently, these FPCs did not receive the letters from the author. It is probable that FPCs with little substantive activity were not included. Regarding the Saga prefecture, the author only focused on 1 ANA. Thus, the present study should be understood as case studies aimed at naturalistic generalization, a process through which readers gain insight by reflecting on the details and descriptions presented in case studies [23].

Part of the data has been published in Ota [24] and Ota [25]. The present study reorganizes the already-published information in terms of its purpose and adds qualitative information that Ota [24] and Ota [25] did not present.

#### **3. Results**
