Evaluation of the resistance of coastal Pinus thunbergii Parlat. forests to the tsunami fluid force in Japan

Abstract

Coastal forests can protect coastal areas from the effects of tsunamis. However, the coastal forests of Tohoku were destroyed by the Great East Japan Tsunami, which was triggered by a gigantic earthquake in the Pacific Ocean on 11 March 2011, causing considerable loss of life and widespread socioeconomic damage. To ensure they have a role in protecting coastal areas from the effects of tsunamis, we need to quantitatively evaluate the resistance of coastal forests to the effects of tsunamis. In this study, the critical velocities required to overturn or break the stems of Pinus thunbergii Parlat. trees were calculated from data collected during a field survey in Aomori Prefecture, Japan. The results showed that the damaged and undamaged trees had small and relatively large critical velocities, respectively. Further, trees with larger diameters tended to be overturned rather than broken. Our results are consistent with those of previous studies, which suggests that the critical velocity could be used to evaluate quantitatively evaluate the resistance of coastal forests to the effects of tsunamis.