Occurrence of Witches' Broom in Cherry Trees in Hakodate, Sapporo, and Asahikawa in Hokkaido Prefecture and Potential Utilization of Cherry Wood

Abstract

We previously investigated the damage caused by witches' broom of cherry to Somei-yoshino (Prunus × yedoensis) and Oyama-zakura (Prunus sargentii) trees in the Shonai region of Yamagata Prefecture, Japan. We found that the disease prevalence was higher in Somei-yoshino due to the lack of pruning of infected branches, while Oyama-zakura had a lower prevalence. In the present study, we extended our investigation to Hokkaido, focusing on Somei-yoshino trees common in Hakodate and Sapporo, and Oyama-zakura trees prevalent across Hokkaido. In Hakodate, the disease prevalence in untreated Somei-yoshino trees was 78%, similar to that in Shonai. In Oyama-zakura, the prevalence was 53% in Hakodate, where pruning was also not performed. In contrast, in Sapporo and Asahikawa, where management practices were implemented, the prevalence in Oyama-zakura was 0% and 5%, respectively, indicating the importance of treatment. The study found that disease symptoms were more severe in trees with a diameter at breast height greater than 40 cm in Somei-yoshino and 30 cm in Oyama-zakura. The estimated total volume of logs and branches was 0.40 m³ for Somei-yoshino and 0.28 m³ for Oyama-zakura, comparable to that of Cryptomeria japonica of the same size. Cherry trees logs can be used as flooring material, and the branches can be used as smoking chips and fuel.