Edge effects from a natural evergreen broadleaved forest patch on advanced regeneration and natural forest recovery after clear-cutting of a sugi (Cryptomeria japonica) plantation

Abstract

We analyzed the biological edge effects of a secondary evergreen broadleaved forest (secondary forest) on advanced regeneration before logging and the germination of seedlings after logging in an adjacent sugi (Cryptomeria japonica) plantation. The edge effect appeared to influence the understory of the sugi plantation up to 20-30m from the edge of the adjacent secondary forest. Particularly, the frugivore-dispersed species such as Persea thunbergii and Daphniphyllum teijsmannii had higher individual numbers than gravity-dispersed species such as Quercus gilva, Castanopsis cuspidata var. sieboldii and Quercus hondae, occurring in relatively large numbers in distant sub-plots from the edge. We suggest recovery of the logged stand to evergreen broadleaved forest will be relatively fast up to about 30m from the edge because the edge stands contained many individuals originating from advanced regeneration, including some that regenerated by resprouting after logging. The regeneration of new seedlings of evergreen broadleaved forest species was also concentrated towards the edge after logging. In particular, there were many more seedlings of frugivore-dispersed species such as Persea thunbergii and Cinnamomum camphora than gravity-dispersed species such as Quercus glauca and Castanopsis cuspidate var. sieboldii. The adjacent secondary forest enhanced early recovery at the edge of the logged forest through both seedling establishment and advance regeneration.