Rainfall interception in an intensively managed low density stand of bamboo, Phyllostachys pubescens

We observed the rainfall interception (Ic) in an intensively managed low density Phyllostachys pubescens Mazel ex Houz. stand. The stand had been managed to maintain 2,000 culms ha–1 by felling old culms and harvesting bamboo shoots. Gross rainfall (Rf), throughfall (Tf) and culm flow (Cf) were monitored over a 10-month period, and Ic was quantified by a water balance method. Rf, Tf and Cf during the experimental period were 2,100, 1,786 and 102 mm, respectively, which resulted in an Ic of 212 mm. The proportions of Tf, Cf and Ic to Rf (i.e. Tf/Rf, Cf/Rf and Ic/Rf, respectively) were 85%, 5% and 10%, respectively.The observed interception ratio, Ic/Rf, in our site was comparable to those reported in other unmanaged P. pubescens stands with higher densities (around 4,000–7,000 culms ha–1). Ic/Rf in both managed and unmanaged P. pubescens stands was generally lower than that in other coniferous and broad-leaved stands in Japan. These findings substantially extend the application range of previous results for Ic/Rf in unmanaged P. pubescens stands. The rainfall partitioning (i.e. Tf/Rf and Cf/Rf) in P. pubescens stands was influenced not only by stand density and culm size but also by the age distribution of culms. Our results stress the importance of considering the culm age distribution when quantifying Ic in P. pubescens stands with the water balance method.