桂竹林之生長特性與崩塌擴張潛勢之探討

本研究探討桂竹生長特性、根系剖面、根力行為以及桂竹林之崩塌原因。研究顯 示桂竹屬地下莖密度高，主要分布於土層 0-30 cm深度處，大多成純林之林相，較一般 樹林單調且多樣性低。鬚根集中於土層0-60cm深度處，最深約可達70 cm，具有固結土 壤與防止地表沖蝕之功能。在土壤深度60 cm之範圍，依土壤剖面內之根面積比與單根 之抗拉強度，可推算桂竹根系所能提供之土壤剪力強度增量值△Sr。同時，此增量值之 大小主要視地下莖之數量而定。另外，依據現地試驗結果及觀察資料，可綜合評估桂 竹林地之崩塌特徵、崩塌地擴張潛勢、以及桂竹根系對坡地崩塌之作用與影響。This study investigates the growth characteristics, root system profile, root mechanical behavior, and collapse-causing factors of Guizhu bamboo. The study reveals that Guizhu has a high rhizome density, mainly distributed in the 0-30 cm soil layer. Most of its stands are pure bamboo forests, which are relatively monotonous and have lower biodiversity compared with common tree forests. Its fibrous roots are concentrated in the 0-60 cm soil layer, with a maximum depth of approximately 70 cm, and they serve the functions of consolidating soil and preventing surface erosion. Within the 0-60 cm soil depth range, the incremental soil shear strength value △Sr provided by the Guizhu root system can be calculated based on the root area ratio within the soil profile and the tensile strength of individual roots. Meanwhile, the magnitude of this incremental value mainly depends on the quantity of rhizomes. Additionally, based on field test results and observational data, the collapse characteristics of Guizhu forest lands, the potential for collapse site expansion, and the role and impact of Guizhu root systems on slope collapse can be comprehensively evaluated.