One of the challenges for sustainable forest management in Japan is the small and dispersed ownership structure of private forests, but new types of cooperation among forest owners have begun to emerge, such as group forest certification. However, these grouping structures vary from region to region and have not yet led to the intensification of forest management and its nationwide development. The purpose of this paper is to present a typology of the grouping structure of small- and medium-scale forest owners in each country by clarifying the acquisition structure of group certification through field surveys, data analysis and literature searches in Sweden, Finland, and Germany, which are regions where group certification has been developed. As a result, the following three typologies are presented: (1) Sweden; Freely competitive groups based on organizations responsible for forest management services to owners, such as forest owner associations and forest production companies (individual organization type), (2) Finland; regional groups based on forest management cooperatives that exist in all over the land (national organization type), (3) Germany; State-based regional groups of state, common and private forests (local organization type). This study clarifies that each three countries has standardized the grouping structure of forest management, and has strategically selected and built sustainable and efficient certification systems by adhering to certification standards and reducing costs.

To examine the impact of bud pruning in the correction of stem crookedness of Melia azedarach, three clones (types 1, 18, and M) were planted at a rate of 1,100 trees/ha in young M. azedarach stand and bud pruning was performed up to a height of 4.5 m above ground. Subsequently, in two years, the number of treatments, aboveground height, stem crookedness per 4 m length (maximum camber), and diameter growth were compared to those of a control non-pruned plot. A reduction of diameter growth was observed in the test plot as compared to the control plot, but there was no difference between clones within the same treated plot. Compared to other clones, the M type not only had a small total number of sprouts but also had less growth on its elongated stems (2.5 to 4.5 m above the ground) in the 2nd year. Hence, it was considered to be a clone that could reduce the cost of bud pruning. The maximum camber in the test plot ranged between 2.22-2.56 cm, which was significantly less than that of the control plot (11.20-15.33 cm). The maximum camber between clones was significant in the control plot but not in the test plot. Thus, bud pruning could correct stem curvature regardless of clones. The findings from this study suggest that bud pruning of M. azedarach may contribute to the consistent production of straight stem.