Fraxinus lanuginosa

Family: Oleaceae
English: Japanese Ash
Japanese: アオダモ (Aodamo)

Easy to miss except when the white flowers are blooming, and then it is easily spotted on mountainsides. [九州野山の花] says it is used in the production of baseball bats. This may be the form noted as f. serrata. Note that Sorbus comixta is also sometimes referred to as Japanese ash.

References:
九州野山の花 片野田逸朗,2004：南方新社
米倉浩司・梶田忠 (2003-)　「BG Plants 和名－学名インデックス」（YList），http://ylist.info（ 2016年9月4日）.