生物多様性管理と林業ジャーナル

Tensile Strength of Moso Bamboo Rhizome Affects Slope Stability

Akihiro Miyagi and Iwao Miyosi

Recently bamboo forests unmanaged spread into steep slopes raising concern that such changes in vegetation might lead to slope destabilization. Thus knowledge on the tensile strength of bamboo rhizomes is needed for evaluating the effect of bamboo rhizomes on slope stability. However there are not many reports on the subject. In addition, because bamboo rhizomes and woody roots have different organization structures, these need to be tested for bamboo. This paper reports the tensile strength of Moso bamboo (Phyllostachys pubescens) rhizomes based on tensile tests considering their organization structure and on living rhizomes. Tensile strength was weaker in nodes than in internode of Moso bamboo, and structure observation revealed that, tensile strength decreased in areas where tissue fibers were discontinuous. The sectional area of the epidermal layer that affected tensile strength was directly proportional to cross sectional area. Because according to a
previous report rhizome diameter was smaller in unmanaged than in managed bamboo forests, so unmanaged bamboo forests might reduce slope stability.