Changes in Runoff Responses After Replantation Following Clearcutting in a Mixed Forest Headwater Catchment

This study examined changes in runoff responses in a 17.8 ha catchment, with a focus on quick and delayed runoff components associated with logging and replantation. In total, 176 precipitation events were observed from 2011 to 2019, including in the pre-cutting, operation, and post-cutting periods. Approximately 70% of the catchment, which was originally dominated by Pitch pine (Pinus rigida), was clearcut between November 2013 and November 2014 and subsequently replanted with Japanese cypress (Chamaecyparis obtusa). Event-based results revealed that both quick and delayed runoff increased significantly under high-magnitude precipitation events (Pt > 60 mm), indicating that rainfall intensity primarily controlled the generation of event runoff. During the operation period, increases in quick runoff contributed to a larger quick-runoff fraction, whereas in the post-cutting period, replantation promoted hydrological recovery by increasing delayed runoff and extending the flow duration. These changes reflect shifts in internal hydrological pathways associated with forest removal and regrowth. Overall, the results highlight that the runoff responses to clearcutting and replantation are strongly mediated by event-scale runoff components and rainfall intensity.