自生する数種の広葉樹の力学的特性に及ぼす環境条件の影響

抄録

In order to clarify the mechanical behavior of living trees, bending tests were carried out. Two sites in the Miura peninsula where wind blows second strongestly in Kanagawa Prefecture, one site at the tip of the peninsula and the other in a valley about 300m inland, were chosen for the study. The mechanical properties (σ_m, ε_m and U_m: stress, strain and strain energy at maximum load) were determined by three point loading bend test. The species in bending were Enoki (Celtis sinensis var. japonica), Mochinoki (Ilex integra), Hisakaki (Eurya japonica), Tobera (Pittosporum tobira), Masaki (Euonymus japonicus) and Yabunikkei (Cinnamomum japonicum).
The experimental results obtained can be summarized as follows:
(1) σ_m were not independent of the part or branch size of the tree.
(2) ε_m decreased with an increase in sample size.
(3) σ_m was higher in stronger wind than in weaker wind.
(4) U_m was higher in stronger wind than in weaker wind.
(5) The ratio of the strain energy per volume U_m/V to σ_m·ε_m/24 did not depend on wind conditions, so σ_m·ε_m/24 could be a mechanical index for the particular species.
(6) U_m/V was in proportion to ε_m.