Possibilities of Using UAV for Estimating Earthwork Volumes during Process of Repairing a Small-Scale Forest Road, Case Study from Kyoto Prefecture, Japan

Although forest road networks are an important infrastructure for forestry, recreation, and sustainable management, they have a considerable effect on the environment. Therefore, detailed analysis of various benefits associated costs network construction is needed. The cost earthwork in can be estimated based change topography before after construction. However, accurate estimation volume may not possible steep terrain where soil placement limited. In this study, unmanned aerial vehicle was flown under tree canopy six times during repair work to measure changes using structure from motion analysis. Comparing obtained 3D model with measurement results total station, average vertical error root mean square were −0.146 m 0.098 m, respectively, suggesting its good accuracy measuring volume. Compared amount topographic work, actual 3.5 greater cutting 1.9 filling. This method used calculate accurately designing terrain.