This study provided an investigation of active root tree zone which is located at the toe of a slope. This section of slope generated matric suction due to tree water uptake. A field monitoring program was carried out to collect matric suction data at slope with two conditions; in absent of a tree and with a tree (Acacia Mangium) located at toe of slope on a tropical residual soil. This soil suction collection is very important to determine the moisture content in soil. When the soil suction is low, it means that the soil is lack of water, which increase the shear strength of the soil compare to soil with more water content. The variation in matric suction values and matric suction profiles response to the tree water uptake and rainfall are investigated. Three soil instruments known as tensiometer and gypsum block (both for suction collection) together with rain gauge (for rainfall collection). Matric suction significantly increased at vicinity of tree at toe of slope compared to slope without tree. The variations of matric suction response due to climate change occur significantly at swallow of the slope and decrease gradually with depth. The decreases of matric suction occur after long duration of intense rainfall. This act as an initial condition before the water uptake driven by active root tree generate to maximum matric suction (low moisture content). Analyses from matric suction profiles revealed that majority of matric suction changes were greater near tree trunk (<4 m) and at shallow depth (0.5 m). The contours of matric suction profiles are presented to reveal moisture flow due to tree water uptake. This investigation provides the viewed contribution of single mature tree significantly alter the matric suction or moisture variation distribution driven by transpiration in an unsaturated soil slope. It takes consideration that preserving mature tree can improved soil properties in modern slope designs.

这项研究提供了位于斜坡脚趾处的活动根树区域的调查。由于树木吸收水，这部分斜坡产生了矩阵吸力。进行了现场监测程序，以在两个条件下收集坡度上的基质吸力数据。在没有树木的情况下，并且在热带残留土壤的斜坡脚趾处有树木（相思树）。这种土壤吸力的收集对于确定土壤中的水分含量非常重要。当土壤吸力低时，意味着土壤缺水，与含水量更大的土壤相比，土壤的抗剪强度增加。研究了基质吸水值和基质吸水曲线对树木水吸收和降雨的响应变化。三种土壤仪器，称为张力计和石膏块（均用于抽吸收集），以及雨量计（用于降雨收集）。与没有树的斜坡相比，在树的脚趾处树附近的基质吸力显着增加。由气候变化引起的基质吸力响应的变化在斜坡的吞咽处明显发生，并随深度而逐渐减小。长时间的强降雨后，基质吸力下降。这是在主动根树驱动的吸水量产生最大基质吸力（低水分含量）之前的初始条件。从基质吸力剖面分析表明，大多数树干吸力变化在树干附近（<4 m）和浅层深度（0.5 m）更大。展示了基质吸力轮廓的轮廓，以揭示由于树木吸收水而产生的水分流。这项研究提供了单个成熟树的观察到的贡献，显着改变了非饱和土壤边坡蒸腾作用驱动的基质吸力或水分变化分布。考虑到保存成熟的树木可以改善现代边坡设计中的土壤特性。