Abstract: Plantations of broadleaf species on karst mountains were investigated in Pingguo, Guangxi, to evaluate their understory biodiversity and community composition in relation to 9 habitat variables and 1 standtype factor by TWINSPAN classification, redundancy analysis (RDA) and canonical correspondence analysis (CCA). The results showed that slope position of plantations was the main factor dominating understory species composition, while rock exposure and site steepness contributed most to the distribution of harmful species. Effects of habitat factors were higher than that of standtype factor, and the former explained 23%-55% of variance in species composition, while stand type approximated 11%-17% of the variance. There were more harmful herb species on terraces than on slope lands, but fewer harmful shrub species on terraces. However, many harmful species flourishing in compulsively conserved karst mountains in Guangxi were absent in the plantations.

Key words: carbon pool, intensive management, nitrogen pool, Moso bamboo forest, soil enzyme