2026 Volume 52 Issue 2 Pages 191-197
This study investigated the effects of summer heat and winter seasonal winds on the broad-leaved trees planted as windbreaks on farmlands in Hokuei town, situated in the Hojo Sand Dunes of Tottori Prefecture. We also aimed to identify techniques for improving tree survival in the sand dune environment. We surveyed the conditions of the planted trees (Euonymus japonicus, Pittosporum tobira, and Ligustrum japonicum) and their surrounding environments in September 2024 and March 2025. The saplings were planted by landowners. The September survey revealed survival rates of approximately 40, 20, and 50% for E. japonicus, P. tobira, and L. japonicum, respectively. The surviving individuals were healthy. In the March survey, survival rates for all species remained largely unchanged from those in September; however, L. japonicum that showed minor damage, such as branch dieback, increased significantly. Overall, E. japonicus and P. tobira suffered high mortality because of summer heat and drought, but the trees that endured the summer maintained good health even under winter monsoon. Conversely, L. japonicum exhibited a higher survival rate during summer, but was more susceptible to seasonal winds, resulting in frequent minor damage. Across all species, individuals irrigated with agricultural sprinklers showed higher survival rates. This suggests that using sprinkler systems is an effective measure for mitigating drought stress and enhancing survival rates.
