Hydrological properties of soil layer are determined by various kinds of heterogeneities, and these heterogeneities give large influences to hydrological processes in the soil layer. Of these heterogeneities components present in the forest soil, this study focused on the common and abundant forest roots, as intended to quantitatively assess the influence its presence on the movement of rainwater in soil layer, vertical infiltration experiment using a pseudo roots was carried out. As a result, the presence of forest roots significantly affects behavior of rainwater in soil layer was revealed, such as, reduced the startup time of groundwater runoff and increased the amount of groundwater runoff. In addition, the startup time of groundwater runoff and the amount of groundwater runoff were able to approximate by using circumferential length of pseudo roots and sprinkling intensity, were confirmed.

Key wordsFheterogeneity, forest roots, vertical infiltration experiment, slope stability