Key Facts
• Oak wilt damage has rapidly expanded in 2025, affecting over 60,000 trees last season.
• Aomori Prefecture began tree removal in October to avoid the active period of the oak ambrosia beetle.
• The beetle, which spreads the oak wilt fungus, is most active from June to September.
• Removal efforts started at Aoi Mori Park in Aomori City, where two trees were affected.
• September was designated as a survey month to assess the current season’s damage.
• A meeting with related organizations to discuss future measures is scheduled for October 28.
Summary
Aomori Prefecture has initiated tree removal efforts in response to the rapid spread of oak wilt, which caused record damage to over 60,000 trees last season. The removal is strategically timed to avoid the active period of the oak ambrosia beetle, the primary carrier of the oak wilt fungus, which is most active from June to September. Initial efforts are focused on Aoi Mori Park in Aomori City, where two trees were confirmed to be affected. September was designated as a survey month to evaluate the extent of this season’s damage, and a meeting with relevant organizations is planned for October 28 to discuss future countermeasures. These efforts aim to mitigate the impact of this worsening ecological issue.
