The effect of converting a native broad-leaved forest to a coniferous plantation forest on annual water yield: A paired-catchment study in northern Japan

This study examined the change of water yield when a broad-leaved forest is converted to a coniferous plantation forest after clear-cutting in northern Japan where monthly precipitation is evenly distributed. Annual water yield after clear-cut was greater than observed in a broad-leaved forest and then decreased with the growth of a coniferous plantation forest. This reduction ceased after 30 years from the planting of coniferous seedlings. Water yield of a coniferous forest at this stage was smaller than observed in a broad-leaved forest. Results from monthly water yield examinations suggested that the difference in annual water yield was primarily caused by the difference in winter interception loss between broad-leaved deciduous and coniferous evergreen forests. The above results suggest that converting coniferous forests into broad-leaved forests can be used to increase water yield in these regions.