Ecological responses of natural and planted forests to thinning in southeastern Korea: a chronosequence study

Effects of forest thinning on community level properties have not been understood yet in Korea. We investigated regenerationpatterns and trajectories after a disturbance by applying a chronosequence approach. Light availability, litter andwoody debris cover, and species composition were determined for twenty 50 m line-transect samples representing a disturbanceduration gradient (within 11 years). Environmental factors such as light availability and coverage of woody debrisand litter changed abruptly after thinning and then returned to the pre-disturbance state. Although species richnesswas gained at shrub and ground layer in a limited way in both forests, cover of various functional types revealed diversityin their responses. Notably, Alnus firma stands exhibited a larger increment of cover in woody plants. Ordination analysisrevealed different regeneration trajectories between natural and planted stands. Based on ordination analysis, rehabilitatedstands showed movement to alternative states compared with natural ones, reflecting lower resilience to perturbation(i.e., lower stability). Our results suggest that community resilience to artificial thinning depends on properties ofthe dominant species. But to get more explanatory ecological information, longer-term static observations are required.