2015 Volume 41 Issue 1 Pages 15-20
Trees can be uprooted by typhoons which have intensive rainfall and strong winds. The ability of the tree to resist uprooting could depend on tree root systems in the soil. In this study, to clarify the difference in pull-out resistance between tree species (Cryptomeria japonica (L. fil.) D. Don) and unpalatable shrub species (Pieris japonica (Thunb.) D. Don and Edgeworthia chrysantha Lindley) , we carried out pull-out tests of root segments. As a result, the pull-out resistances of the roots in 10 mm basal diameter in C. japonica (1012.3 N) and P. japonica (844.3 N) were stronger than that in E. chrysantha (200.1 N). On the other hand, the soil reinforcement (i.e. sum of the pull-out resistance per soil profile 1 m2) was largest in C. japonica (26.8 kN) , and followed by P. japonica (15.1 kN) ,and was smallest in E. chrysantha (1.0 kN). Our results suggest that taking advantage of the characteristics of each unpalatable shrub species improve the soil reinforcement in a site heavily used by sika deer (Cervus nippon Temminck) .
