Abstract: Size inequality is ubiquitous in plant populations. Studying its influence on community productivity and species diversity is of significance for natural secondary forest management. We selected 7 plots of typical subtropical secondary forest communities in the Lishui Forest Farm, Jiangsu Province. We studied the relationship between the coefficients of variation (CV) of tree height and diameter at breast height (DBH), aboveground biomass and species diversity index (Shannon index). The results showed that, (1) the CV of tree height was less than that of DBH, but its impact on the community biomass and species diversity was generally greater than that of DBH inequality. (2) In the broadleaved mixed forest (with a low canopy cover) dominated by Pinus massoniana, community biomass was positively correlated with individual size inequality, while a negative correlation was found in the deciduous broadleaved forest and in the broadleaved mixed forest dominated by Cunninghamia lanceolata (with a higher canopy cover). (3) Species diversity was positively correlated with size inequality, but the relationship was weak in the community with low canopy cover. In summary, individual size inequality was beneficial for increasing species diversity, and had a positive effect on aboveground biomass of low cover communities.

Key words: nitrogen storage., plantation forest, carbon storage, forest age