SPECIAL ISSUE “ Roles of revegetation for preventing Sediment Disaster ”
Current status and challenges for non-destructive evaluation of tree roots using ground penetrating radar from disaster mitigation aspects

Abstract

Estimates of root system structure in forest trees can contribute to provide effective proposals to mitigate natural disasters such as slope slides and tsunami. Here, we review recent new findings of cutting-edge research on non-destructive root detection using ground penetrating radar (GPR) under experimental and forest field conditions and propose challenges for future research for applying to forest trees in Japan. The water contents of roots and soils, root orientation, the selection of appropriate antenna, and extraction of reflected wave parameters of GPR are crucial factors to detect and estimate root structure in field conditions. Successful root detection and estimates of root biomass in several tree species have been reported in sandy optimal soil conditions in many countries, particularly in United States. However, the utility of GPR for forest trees is still site specific. One of the optimal sites is coastal pine forests in Japan. The effects of slope conditions and heterogeneous forest soils on the root detection should be clarified before the application of GPR to forest trees in Japan.