On the chugoku-zasa(Sasa veitchii var. hirsuta) communities growing at Sanbe Forest of Shimane University, a comparison was made between those in open plots and those in under-tree plots. Ten sampling Plots of each were selected. Half of them were mowed at the end of March and the rest left were untouched. The results of the observation were as followed :
1. In the untouched open plots, 18% of the old stems, 30% of the old branches and 40% of old leaves died from May to November and replaces by new ones.
2. In the untouched under-tree plots, the branches and leaves became less in number of culm in November than in May.
3. In the mowed open plots, the regenerated stems recovered only 40% in number of old stems. In the under-tree plots the degree of recovery was less than in open plots.