Abstract: The allocation of biomass and energy in nine different 3-year-old stands was studied in a mixed planting trial with four tree species namely Eucalyptus leizhou No.1, E. exserta, Acacia auriculiformis and A. mearnsii. Comparing the contribution of various components to the total biomass production among the trial stands showed that 58%~66% biomass production was recorded in stem-wood, and 6%~14%, 5%~9%, 13%~16% and 4%~8% biomass production was produced by branch-wood, leaves, roots and litter, respectively. Results obtained for energy content is similar to the result of biomass production. Among the nine stands studied, the mixed stand of E. leizhou No.1 and A. auriculiformis with the mixed proportion of 1:1 by rows found to be the most productive planting system adapted for large-scale plantation management.