抄録
In this study, we conducted field-based pulling tests using the PiCUS TreeQinetic (manufactured by IML) to measure the bending strength of green wood. Pulling tests were performed on dead trees and damaged branches affected by the oak ambrosia beetle (Platypus quercivorus), and stress-strain curves were derived from the test results. These findings suggest that the wood strength of trees damaged by the beetle declines as a result of infestation. In contrast, stress-strain curves obtained from ginkgo (Ginkgo biloba) branches during the fruit-bearing period showed less clearly defined linearity in the elastic region compared to those of infested Quercus serrata (konara oak). Notably, for female ginkgo branches with a diameter of 33 mm, considerable variability was observed in the scatter plots. When conducting pulling tests in the field, it is necessary to consider the effects of factors such as the diameter and species of the tested green wood, as they may influence the results. Moreover, by calculating the stress caused by the self-weight of fruit-bearing ginkgo branches, we were able to evaluate the potential risk of branch breakage due to self-loading.
