Abstract
An investigation was undertaken into the generation of overland flow and vegetation recovery on a spur road constructed at the time of thinning at the Nagasaka Experiment in Akita Prefecture, Japan. The vegetation coverage and the number of species were low, both on the cut slope and in wheel tracks on the upslope side of the road. Frost heave, snowmelt, and raindrop splash on the cut slope were considered factors that affected vegetation recovery, which contributed to the continuous overland flow in the wheel tracks on the upslope side. The intercepted subsurface flow from the cut slope, in addition to the inflow to the spur road from a stream channel, was observed as a source of overland flow. This overland flow occurred over 21.2％ of the entire length of the spur road within the watershed, and field observations suggested that this fragmented overland flow was caused primarily by intercepted subsurface flow. Moreover, overland flow was generated on the road during the snow season in the same locations as in the non-snow season. This study establishes that when constructing spur roads in watersheds, it is important to determine both the source of the subsurface flow and the locations of stream channels.
