Abstract
The effects of thinning and litter removal treatments on the establishment of riparian vegetation were investigated in a Cryptomeria japonica plantation. The number of germinated seedlings and species richness were significantly greater in the plots that were thinned (30% and more) than in the control or girdling plots. Litter removal also encouraged the germination of many species, resulting in greater numbers of seedlings and species. Thinning increased the number of component species of natural riparian forests. However, the established understory vegetation was dominated by Euptelea polyandra, while Pterocarya rhoifolia and Fraxinus platypoda, the typical canopy trees of natural riparian forests, and several regional riparian perennial herbs were absent. These results suggest the possibility of natural regeneration of riparian species in managed forests, and the need for long-term monitoring to establish optimal management practices, including planting, for the restoration of semi-natural riparian forests.
