2种西南桦人工林与同地2种天然次生林的林分生物量对比研究

Comparison of Biomass of Betula alnoides Plantations and Natural Secondary Forests in Xishuangbanna

采用样地法对西双版纳13年生的西南桦纯林和西南桦+肉桂混交林两种西南桦人工林林分的生物量进行了测定,并与当地相同林龄的天然西南桦次生林和热带次生林进行了对比研究。结果表明:西南桦+肉桂混交林的生物量最大,为136.94 t/hm2,西南桦纯林次之,为115.89 t/hm2,西南桦次生林为102.48 t/hm2,热带次生林为68.19 t/hm2。西南桦+肉桂混交林林分生物量的年增长量达9.18 t/hm2,西南桦纯林为8.02 t/hm2,西南桦次生林也达到了7.42 t/hm2,热带次生林为4.84 t/hm2。4种林分中,地上部分生物量最大的是西南桦+肉桂混交林,达91.22 t/hm2,最小的是热带次生林,仅46.16 t/hm2,西南桦纯林和西南桦次生林分别以84.35 t/hm2和80.23 t/hm2居中;地下部分生物量方面,西南桦+肉桂混交林最大,为28.11 t/hm2,西南桦纯林以19.48 t/hm2位居其次,西南桦次生林与热带次生林差异不大,分别为16.20 t/hm2和16.81 t/hm2;凋落物层生物量方面,西南桦+肉桂混交林最大,为17.61 t/hm2,西南桦纯林以12.06 t/hm2位居其次,西南桦次生林为6.05 t/hm2,大于热带次生林的5.22 t/hm2。

Adopting the method of sample plot, the biomass of 13 years old Betula alnoides plantation and the mixed plantation of B. alnoides with Cinnamomum cassia in Xishuangbanna were measured, and were compared with the natural B. alnoides natural secondary forest and tropical secondary forest. The study results showed that the mixed plantation had the highest biomass of 136. 94 t/hm^2, next came the pure B. alnoides plantation of 115.89 t/hm^2, B. aZnoides natural secondary forest and tropical secondary forest had the biomass of 102. 48 t/hm^2 and 68. 19 t/hm^2 respectively. The annual growth of the mixed plantation, pure plantation, B. aZrtoides natural secondary forest and tropical seeondary forest were 9.18 t/hm^2, 8.02 t/hm^2, 7.42 t/hm^2 and 4.84 t/hm^2 respectively. Among the four types of forests, the ranking of aboveground biomass were mixed plantation of B. alnoides and C. cassia, pure B. alnoides plantation, B. alnoides secondary forest and tropical secondary forest, with the biomass of 91.22 t/hm^2, 84. 35 t/hm^2, 80. 23 t/hm^2 and 46. 16 t/hm^2 respectively. The ranking of underground biomass were mixed plantation of B. alnoides and C. cassia, pure B. alnoides plantation, tropical secondary forest and B. alnoides secondary forest,with the biomass of 28.11 t/hm^2, 19.48 t/hm^2, 16.81 t/hma and 16.20 t/hm^2 respectively. The litter biomass of mixed plantation of B. aMoides and C. cassia, pure B. alnoides plantation, B. alnoides sec0hdary forest and tropical secondary forest were 17.61 t/hm^2, 12. 06 t/hm^2, 6. 05 t/hm^2 and 5.22 t/hm^2 respectively.