Abstract
The authors studied the changes in return, uptake and biomass of materials with the change of site condition along the slope in a deciduous broad-leaved forest. The biomass and mineral of trees were low in N-4 stand located on upper part of slope, and they reached 27_??_30% of N-7 stand located on lower part of slope. The amounts of materials present in A0 layer were higher in upper part plot than in lower part plot. On the contrary, the amounts in mineral soil were lower in upper part of slope. The amounts of uptake of nutrient elements by trees and return including small litter collected by litter trap, big branches and rain water, were lower in upper part of slope. The rate of turn-over was calculated as the ratio of the amounts of return to the amounts of materials presented in A0 layer and total soil (A0 layer and mineral soil to 70cm in depth). The rate of all materials for A0 layer tend to be low on the upward slope. The rate for total soil, however, had no definite relation to the part of slope. The rate of calcium for total soil was considerably higher at the upper part of slope than at the lower part of slope. This meant that the circulation of materials in stand located on the upper part of slope was not as slow as the rate of litter decomposition, which was low in the upper part of slope
