VARIATION IN SUSCEPTIBILITY TO WIND ALONG THE TRUNK OF AN ISOLATED LARIX KAEMPFERI (PINACEAE) TREE
VARIATION IN SUSCEPTIBILITY TO WIND ALONG THE TRUNK OF AN ISOLATED LARIX KAEMPFERI (PINACEAE) TREE
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DOI：
10.3732/ajb.1400135
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发表时间：
2014-07-01
影响因子：
3
通讯作者：
Tateno, Masaki
中科院分区：
文献类型：
--
作者：
Minamino, Ryoko;Tateno, Masaki
研究结论：风力对树木的生存是一个重大的危险，并会影响树木的形态。然而，实际分布的应力，风的原因，树干并没有得到很好的理解，尽管其预期的重要性，树木形态。均匀应力假设（即，树干采取使应力沿着树干外表面均匀分布的形式）已经作为模型进行了间接测试，高度重视树干的机械安全性，并且在理论上被拒绝。但是树干上的应力还没有被直接测量。方法：在树干上的七个高度上测量了一棵日本落叶松树在风荷载作用下树干表面的实际应变，持续1年。关键结果：在测量期间，无论风速如何，树干上部的风致应力都高于下部，并且随着风速的增加，差异增大。在每个位置记录的树干的偏转也较大的上部比在较低的portions.Conclusions：结果表明，一个孤立的日本落叶松树的树干的上部比下部更容易受到风的影响。这些结果不支持均匀应力假设，并建议另一种限制（无论是机械或非机械）的树的形态上的行为。
Premise of the study: The force of the wind is a significant hazard to the survival of trees and can affect tree morphology. However, the actual distribution of the stress that wind causes to a tree trunk is not well understood in spite of its expected importance to tree morphology. The uniform stress hypothesis (i.e., tree trunks take a form that equalizes the distribution of stress along the outer surface of the stem) has been tested indirectly as a model, placing high importance on the mechanical safety of a trunk, and rejected theoretically. But stress on a tree's trunk has not yet been measured directly.Methods: Actual strains at the surface of the trunk of an isolated Larix kaempferi tree due to wind loads were measured at seven heights on the trunk for 1 yr.Key results: During the measurement period, wind-induced stress was higher in the upper portions of the trunk than in the lower portions, regardless of wind speed, and the difference increased as wind speed increased. The deflection of the trunk recorded at each position was also larger in the upper portions than in the lower portions.Conclusions: The results indicate that the upper portions of the trunk of an isolated Larix kaempferi tree are more susceptible to wind than are the lower portions. These results do not support the uniform stress hypothesis and suggest that another limitation (either mechanical or nonmechanical) acts on the morphology of the tree.