不同林龄巨尾桉的灰分含量和热值

采用热量仪和马福炉对1～4年生4个不同林龄阶段巨尾桉的叶、枝、根、干、皮5个部位进行灰分含量和热值测定,结果表明:不同林龄巨尾桉其5个部位的平均灰分含量在(0.42±0.14)%～(4.43±1.35)%之间,以皮的最高、干的最低,各部位灰分含量的大小排列顺序无一相同且无明显的规律可循,除根外,叶、枝、干、皮在林分4个...

Ash contents and caloric values of Eucalyptus grandis× Eucalyptus urophylla in different stand ages

Ash contents and caloric values of leaves,branches,roots,stem-wood and bark of 1-4 years old Eucalyptus grandis×Eucalyptus urophylla were determined by using calorimeter and muffle furnace.The results showed that the ash contents of five parts ranged from(0.42±0.14)% to(4.43±1.35)% with the highest in bark and the lowest in stem-wood,the decreasing orders of them at different stand ages were not in the same way and were irregular,there were significant different in ash contents of leaves,branches,stem-wood and bark except roots at four stand ages(P<0.05).Mean gross caloric values(GCV)and ash free caloric values(AFCV)of different parts ranged from(17.24±0.31)to(20.58±0.34)kJ·g-1 and(18.04±0.22)to(21.44±0.37)kJ·g-1 respectively,the distribution law of them at different stand ages were quite different from component to component with leaves having the highest GCV and AFCV and bark the lowest.The differences among stand ages in GCV of leaves,branches,roots and AFCV of leaves,roots,bark were not significant(P>0.05),but making obvious differences in stem-wood and bark's GCV,branches and stem-wood's AFCV(P<0.05).As to the whole tree,4-year-old Eucalyptus grandis×Eucalyptus urophylla had the highest ash content which was 2.76%,while the 2-year-old tree had the highest GCV and AFCV which was 19.06 kJ·g-1 and 19.53 kJ·g-1.To whole tree,the differences in ash content and colaric value were not obvious(P>0.05).