Abstract
The amount of monthly soil loss was measured at 15 stands of Hinoki(Chamaecyparis obtusa) plantations (19-38 years old) in the northern part of Okayama prefecture, to evaluate the relationships between monthly soil loss and rainfall factors, such as monthly rainfall (P), maximum 10-minute rainfall intensity (I_<10>), maximum 60-minute rainfall intensity (I_<60>), P・I_<60> and P・I_<60>・I_<10>. Monthly soil loss in both thinned and unthinned stands tended to be larger in June-October and smaller in November-February. Relationships between monthly soil loss and P, P・I_<60> and P・I_<60>・I_<10> were represented by power equation. Integrated values of I_<10>, I_<30> and I_<60> for a month also showed log-linear relationships with monthly soil loss, while they less explained monthly soil loss than P, P・I_<60> and P・I<60>・I<10>.
