Evaluation of lodging resistance characteristics of broad-leaved tree and Pinus thunbergii planted in coastal sand dunes using tree-pulling experiments

Abstract

Many trees of coastal forests in East Japan were damaged by the Great East Japan tsunami. Since then, the restoration of coastal forests damaged by the tsunami has been in progress. Therefore, the evaluation of the lodging resistance characteristics of the trees of coastal forests is strongly required, but these characteristics have been insufficiently studied for broad-leave tree species. We conducted tree-pulling experiments on Pinus thunbergii and the following broad-leaved tree species of coastal forests : Acer mono var. glabrum, Machilus thunbergii, Quercus crispula, Quercus dentata, and Zelkova serrata. The diameter at breast height(dbh) of the experimental trees ranged from 5 to 15 cm. For each tree species, the critical turning moment at which tree was uprooted increased with the increasing tree size characteristics such as dbh, squared dbh x tree height(dbh²h), and weight of above ground parts of tree (w). The critical turning moment of each tree species was well approximated by the functions of dbh, dbh²h, and w. The critical turning moment of Z. serrata was the largest and that of M. thunbergii and P. thunbergii were the smallest among the six tree species studied.