Removal of leaf biomass at different thinning intensities and its recovery in hinoki cypress plantations were evaluated for a duration of 10 years in Kochi Prefecture, southern Japan. Leaf biomass was estimated using an equation based on the relationship between leaf biomass and basal area of the lowest branch of hinoki cypress, in seven areas across Japan. Before thinning, leaf biomass in the six study plots ranged from 14.9 to 16.9 Mg/ha. After thinning, reduction in leaf biomass ranged from 3.7 to 10.3 Mg/ha, and the percentage of leaf removal (23–69%) was similar to that of stem biomass. After 10 years, leaf biomass ranged from 6.8 to 18.2 Mg/ha. Percentage of recovery of leaf biomass to the leaf biomass reduced by thinning ranged from 21% to 57% during the intervening 10 years. The time needed to attain leaf biomass equal to the amount present before thinning was estimated to range from 18 to 49 years. Strongly thinned forests took a longer time to recover the lost leaf biomass. Moreover, recovery of leaf biomass was slower in plots where the height of the crown base increased owing to the death of the lower branch of the crown. These results suggest that the death of the lower branch is crucial to leaf biomass recovery even in thinned plots, and studies on the estimation of leaf biomass should consider changes in height owing to the death of the lowest branch of the crown.

Collembolan populations were monitored following clear-cutting of a secondary forest at Kyoto city. Since the number of individuals of the rare species increased, the total number of individuals maintained after clear-cutting. Cluster analysis divided main species into groups composed of five major clusters. Drying resistance and high-temperature resistance of species are related to maintenance of number of individuals. On the other hand, collembolan vertical distribution was not influenced maintenance of the number of individuals. It turned out that the collembolan community of a secondary forest shows characteristic correspondence to a disturbance.