نوسانات ماهیانه و سالانه رطوبت خاک در جنگلهای بلوط دچار خشکسالی و خشکیدگی درختی

Following the occurrence of drought and climate change, tree decay occurred in Iranian oak forests. In this regard, the current research has investigated the monthly and annual changes of soil moisture in the oak forests of Maleh Siah region of Ilam in the years 1398 to 1400. To conduct this research, two research sites were selected in the northern and southern geographical directions. In each research site, 10 Iranian oak trees were determined in two classes of healthy and red-broken crown wilting. On the south side of each tree, soil sampling was done at two horizons of 0-20 and 20-50 cm and was taken to the laboratory to measure soil moisture. Soil sampling was done for three years. To determine the monthly changes of soil moisture, soil sampling was done every month during the growing season. To determine the yearly changes of soil moisture, soil sampling was done in August every year. The results showed that the soil moisture level was associated with monthly changes and had a decreasing trend. Also, soil moisture in the research sites showed annual changes. The results of this research indicate that changes in soil moisture are affected by climate changes and drought, and these changes will have a negative role in the survival, life and health of trees.