Effects of thinning intensity on understory vegetation in Chamaecyparis obtusa stands in South Korea

Abstract

The study was conducted to analyze the effects of thinning intensity on understory vegetation in Chamaecyparis obtusa stands. The site was located on Mt Moonsu in Gochang-gun, South Korea and consisted of five treatment plots: 5 m x 5 m quadrats were installed in each plot. The total flora of the C. obtusa stand included 47 families, 60 genera, and 70 species. Three classes of floristic regional indicator plants were verified: six taxa in class I, one taxon in class II, and one taxon in class III. Also, Phytolacca americana and Robinia poseudoacacia appeared as naturalized plants in heavy thinning and control plots, respectively. Their Naturalized Index and Urbanization Index were shown as 1.00% and 0.74%, respectively. Within the treatment plots, the greatest number of species appeared in the heavily thinned plots (31 species). Chamaecyparis obtusa showed the highest dominance index of 4.67. Regarding species richness of understory vegetation, there was a very distinct difference between the thinned and non-thinned plots, whereas there was no significant differences among the treatment plots such as light thinning, normal thinning, heavy thinning, and super heavy thinning plots. Thus, understory vegetation was influenced by the presence of thinning, but not influenced by thinning intensity in this study.