In the present study, the generation mechanism of the wind damage was analyzed to examine the possibility of applying CFD (Computational Fluid Dynamics) technique to the field of the forest dynamics and the forest managements. From the simulation by the latest meso-scale climate model NHM, forest damages by Typhoon No.0418 seemed to be caused by southwestern wind in Kokonoe town, Oita Prefecture, Japan. Based on the results, wind condition around the damaged forests was simulated by using a numerical wind synopsis technology RIAM-COMPACT^[○!R]. As a result, it was considered that there were two main causes of wind damage: 1) the local enhancement of wind speed caused by the topographic effect, and 2) the effect of separated airflow from land surface above the damaged area. As shown in the present study, the CFD technique would be an extremely promising approach in the field of the forest and forestry.