连栽14年生杉木林生态系统生物量的结构特征

Biomass distribution and net primary productivity of a 14-year-old stand of successive rotations of Chinese fir plantation

用空间一致和时间连续的定位研究法,在湖南会同杉木林生态系统国家野外科学研究站,对实验基地连栽14年生杉木林的生物量结构特征进行了研究,并与第1代同龄杉木林的生物量和生产力进行了比较。结果表明:连栽14年生杉木林的林木单株生物量、林分生物量和生产力分别为42.07kg、97.18t.hm-2和6.95t.hm-2a-1,各器官的分配规律为树干>树根>树枝>树皮>树叶;林下植被层生物量为1 318.14kg.hm-2,其中灌木层生物量为475.53kg.hm-2,草本层为842.61kg.hm-2,并在组成与分布上呈现出不均匀状态;林地上的死地被层生物量为6 192.73kg.hm-2,其中未分解层大部分向半分解层和已分解层转移。生态系统中生物量空间分布格局为:杉木层97.18t.hm-2,占92.83%;灌木层0.48t.hm-2,占0.46%;草本层0.84t.hm-2,占0.80%,死地被物层6.19t.hm-2,占5.91%;2代连栽的14年生杉木林生物量和生产力比较,第1代林分生物量和生产力分别为104.45t.hm-2、7.47t.hm-2a-1,比第2代高7.27t.hm-2、0.52t.hm-2a-1,表明第2代杉木林生物量和生产力均下降6.96%。研究结果充分证明杉木连栽对林分生物量和生产力的影响明显,可为杉木林长期生产力的研究及杉木林的可持续经营提供科学依据。

The biomass partitioning and net primary productivity（NPP） of a 14-year-old stand of successive rotations of Chinese fir plantation were investigated at Huitong National Field Station for Scientific Observation and Experiment,Hunan Province,China,using a chronosequence approach on the same experiment site.The results show that mean individual tree biomass,stand biomass and NPP in the second rotation were 42.07 kg,97.18 t·hm-2 and 6.95 t·hm-2a-1,respectively in the studied stands.The proportion of biomass at tree scale was in an order： wood root branch bark leaf.Understory vegetation biomass was 1 318.14 kg·hm-2,of which shrubs and herbaceous biomass were 475.53 kg·hm-2 and 842.61 kg·hm-2,respectively.Dead vegetation biomass on the forest floor was 6 192.73 kg·hm-2.The overstory Chinese fir tree accounted for 92.83% of the total stand biomass,the next was herbaceous（0.80%）,dead vegetation（5.91%） and shrubs（0.46%）.When compared to the same aged stands of the first rotation of Chinese fir plantation on same sites（biomass： 104.45 t·hm-2;NPP： 7.47 t·hm-2·a-1）,biomass and NPP were reduced by about 7% in the second rotation.The findings demonstrate that successive rotations of Chinese fir plantation had considerable effects on biomass production and NPP at middle growth and development stage of the stands,which provides scientific references for sustainable management of Chinese fir plantations.