2011 Volume 53 Issue 1 Pages 17-22
Most of litter returned by non-commercial thinning was existed without contact onto the forest floor. We discussed nitrogen dynamics with decomposing litter after thinning with a focus on the site difference of litter existence in this study. The amount of nitrogen returned by thinning was 84kg ha^<-1> and 67% of them were existed in the air without contact onto the floor. Litterbag containing green needles was installed in the air and on the surface in forest floor, and decomposition rate and nitrogen supply with decomposing of green needles into the soil were investigated. Decomposition rate was not differed among treatments after one year installation but was higher in the surface than the air in two year after. Nitrogen concentration in the remaining green needles was increased from just after installation in both of treatment, and was statistically higher in the surface than in the air. After decomposition, amounts of nitrogen containing in the remaining green needles were gained by immobilization until six month after in the air and one year after in the surface. Nitrogen supply into the soil with green needle decomposition started early in the air compared in the ground. Contribution of nitrogen supply into the soil from green needles installed on the surface during two years was 64%. Because decomposition rate of green needles installed on the surface between one and two year after higer than those of in the air.