Tree falls are crucial disturbances in forest ecosystems. When trees fall, they create gaps in the forest canopy, allowing young trees to grow and facilitating forest regeneration. They are often formed by abiotic factors such as wind and snow. Additionally, certain organisms, including bark beetles and ungulates, can induce tree falls. Among these, woodpeckers may contribute to tree falls by causing external damage when they create tree cavities. However, the relationship between woodpeckers and tree falls has not been thoroughly investigated.

To clarify this relationship, it is essential to consider the factors involved in creating tree falls. In this study, we quantitatively examined the relationships between the abundance of woodpeckers in previous years and the occurrence of tree cavities and tree falls in subsequent years. The surveys were conducted across multiple sites within broad-leaved forest patches in a coniferous plantation landscape. Given that woodpeckers’ ability to excavate cavities likely varies with their size, we analyzed the data separately for large and small woodpecker species.

Our results indicate that the number of woodpeckers is positively correlated with both the number of tree cavities and the incidence of tree falls in the focal years. This suggests that woodpeckers may facilitate gap creation and drive natural disturbances by inducing tree falls. While woodpeckers have been previously recognized for their role in aiding forest regeneration through seed dispersal, our study reveals that they may also contribute to natural disturbances. Future research should focus on investigating how animal-driven natural disturbances affect forest regeneration across various regions. Such studies will enhance our understanding of forest ecosystem mechanisms and improve models that predict future forest dynamics.