Energy characteristics of five Eucalyptus species in Zhangmutou Forest Farm, Guangdong Province.

Energy characteristics of 6-year-old trees of Eucalyptus grandis,E. saligna,E. cloeziana,E. pellita and E. torelliana in Zhangmutou Forest Farm in southern Guangdong Province were studied. The results showed that there were significant differences in ash content and caloric value of various above and below ground components (P0.01). Ash contents ranged from 0.16% to 8.37%,with the components in E. grandis,E. saligna,E. pellita and E. torelliana had order as leaves barkbranches rootsstem-wood,and that in E. cloeziana as barkleavesbranchesrootsstem-wood. Gross caloric values (GCV) of various components ranged from 15.12 to 18.85 kJ g-1 with leaves having the highest GCVs and bark the lowest. For E. grandis and E. pellita,the order of components was leavesbranches stem-woodrootsbark,for E. saligna and E. torelliana was leavesstem-woodbranchesrootsbark and for E. cloeziana leavesbranchesrootsstem-woodbark. Ash free caloric values (AFCV) of components ranged from 16.37 to 19.87 kJ g-1 and the order of components by AFCVs were the same as those for GVCs for E. grandis,E. saligna,E. cloeziana and E. torelliana,and that for E. pellita as leavesbranchesbark stem-wood roots. For whole tree,E. grandis and E. pellita had the highest mean GCV and AFCV values respectively,while E. torelliana had the lowest.