Abstract:The stationarity of streamflows over the past 50years were investigated for well/poorly forested watersheds in the Beiluohe River basin on the Loess Plateau,using concentration degree and concentration period methods.The change trend and change point were checked with nonparametric M-K,Pettitt and Rank-sum tests.Results show that all the five watersheds studied were characterized by the high fluctuation of annual streamflow and the double peaks of inner-annual hydrograph.Forested ones presented mild slopes and less forested ones,steep shapes.In contrast,the streamflows were better distributed in well forested watersheds where the concentration period was 1month behind the poorly forested counterpart.Different components of the streamflow in forested watersheds did not show a significant trend or change point,while significant decrease and change points were detected in annual streamflow and the components in summer,fall and flood season for less forested watersheds in the past 50years.In both annual and inner-annual scales,the streamflow in forested watersheds was considered more stable than that of the less forested,which implies that less forested watersheds still demands a long-term construction and conservation for the eco-environment to recover.