Influence Area of Stem Flow on a Soil of Deciduous Forest Floor by Electric Resistivity Survey and the Evaluation of Groundwater Recharge through Stem Flow

Abstract

The stem flow is volumetrically much less than through fall and it was believed to be less wet around a tree stem than the other part of the forest floor because of rainfall resistance of a tree canopy and little contribution of stem flow. In the present study, the continuous resistivity survey was conducted at the experimental deciduous forest along the one selected line for about 1.5 years’ intervals to observe the seasonal change of soil water content under the tree canopy. The observation results were applied to evaluate the effect of the stem flow on the shallow soil water content around the selected trees. The results clearly show that the downward soil water flux under the tree canopy is 2.2 times larger than that of the no tree area in the study forest. By using this downward flux data with tree density in the study forest, the groundwater recharge rate was calculated. The groundwater recharge through the stem flow is nearly 39.1% in the total groundwater recharge in the study forest, which is completely larger than the tree density of the study forest (0.115m2/m2(1.15%)). This result clearly supports the effect of stem flow on the groundwater recharge in the forested area.