Creating the forest vegetation map of Tohoku region in response to mass mortality of oak trees damage

This paper addresses the management of mass mortality of oak trees damage by creating a forest vegetation distribution map for the entire Tohoku region in Japan. Mass mortality of oak trees, caused by the wilting disease in beech family trees, has decreased nationwide since its peak in 2010, but its northward expansion persists. The Tohoku region, especially in Aomori and Iwate prefectures, experiences damage, indicating the mortality’s reach in even the northernmost areas. The primary strategy against mass mortality of oak trees involves eradicating the Kashinonaga Kikuimushi beetle (Platypus quercivorus), a carrier of the pathogenic fungus on dead trees, making predicting the beetle’s habitat crucial for effective prevention. Building on forecasting methods used in Yamagata Prefecture, this study creates a vegetation distribution map for mass mortality of oak trees in the entire Tohoku region.The map reveals high susceptibility to mass mortality of oak trees in regions such as the Ou Mountains, Tsugaru Peninsula in Aomori, Shimokita Peninsula, Shirakami Mountains, Kitakami Mountains, northern Dewa Mountains, and areas from Chokai Mountain to Asahi and Onnagatake. These regions with abundant Mizunara (Quercus mongolica v.grosseserrats Rehd. et Wils.) and Konara (Quercus serrata Murray var. serrata) raise concerns about damage. Accuracy validation using 2010 mass mortality of oak trees damage data collected in Yamagata Prefecture indicates approximately 50% accuracy, suggesting the map’s reliability for planning preventive measures. Strategies include effective early control for individual trees but emphasize that as damage increases and disperses, the efficacy diminishes, emphasizing the fundamental approach of harvesting, utilizing, and renewing healthy oak forests.