Abstract
We compiled daily data of precipitation and runoff observed from 2006 through 2010 in the Minami-dani and the Kita-dani in the Tatsunokuchi-yama Experimental Watershed of the Kansai Research Center of the Forestry and Forest Products Research Institute. Each day was separated at 0:00 JST. Precipitation data were the sum of hourly mean values of three tipping bucket-type rain gauges arranged at a meteorological station in the Okayama Experimental Forest, which is located at the west-northwest foot of Mt. Tatsunokuchi. For the period from August
2 to December 10, 2006, the data of a storage-type rain gauge were employed because the three tipping bucket rain gauges failed to record data. Runoff data were the sum of water flows converted from water stages measured at 60°V-notch gauging weirs. Water stage fluctuations were recorded using a float-type pen recording water level gauges, and the analogue waveforms were digitized manually. At the Minami-dani, data missing because of mechanical malfunction of the gauge occurred during several hours on May 29 and September 26, 2008. Therefore, runoff data based partly on estimated water stages were employed for these days. For the mean annual precipitation of 1071.2 mm, the mean annual runoff was 315.2 mm in the Minami-dani and 349.9 mm in the Kita-dani during the reporting period. In early 2006, Hinoki （Chamaecyparis obtusa） was planted in the upper slope and four species of broadleaved tree were planted in the lower slope in a 0.48 ha tree windfall area that formed in 2004 because of typhoons. Subsequently, weeding in the planted area was conducted once each year in summer until 2010. However, overall, changes of vegetation cover were not conspicuous in both catchments.
