贵州西部光皮桦天然次生林生物量和净生产力的研究

摘要

2009年,对贵州西部水城县玉舍林场光皮桦天然次生林的生物量和净生产力的研究表明:林分林分平均生物量为48.14t/hm2,各层次的生物量分配顺序为乔木层(70.98％)＞灌木层(13.27％)＞枯落物层(12.05％)＞草本层(3.70％),乔木层占有绝对优势,但灌木层、草本层所占比例还较大,光皮桦对林地地力和空间的利用还不够充分；植被层生物量占了林分生物量的87.95％,地上部分和地下部分分别占了林分生物量的85.79％和12.91％,比值较为合理；乔木层平均生物量为34.17t/hm2,表现为干(52.61％)＞枝(29.26％)＞根(14.99％)＞叶(3.14％)；不同径阶生物量所占比例以中径阶最大(70.44％),林分径阶结构不合理,应加强管理,以促进林木生长；林分净生产力平均为7.34 t·hm-2 a.-1,其乔木层净生产力为4.49 t·hn-2 a-1,占了林分净生产力的61.17％,表现出了较高的生产力,但林下植被层净生产力还较高,占了38.83％,光皮桦对林地的利用还不够充分,应加强管理,进行林分结构改造,提高林分乔木层的净生产力.%Study on the biomass and net productivity of the natural secondary forests of Betula luminifera in Shui Cheng, a western County in Guizhou Province indicated that the average forest biomass was 48.14 t/hm2, shared by the tree story (70.98%), the shrubs (13.27%), litter (12.05%) and grass (3.70%) and the tree story was overwhelmingly predominanl in the biomass contribution while the shrubs and grass had also a comparatively great share; Betula luminifera did not make full use of the land capacity and the space. The vegetation biomass accounted for 87.95% of the forest biomass, and the aboveground and underground parts accounted for 85.79% and 12.91% of the forest biomass respectively, which showed reasonable ratios. The average biomass of the tree canopy was 34.17 t/ hm2 distributed among the trunk (52.61%), branches (29.26%), roots (14.99%) and leaves (3.14%), and among the diameter classes, the middle diameter class contributed the most to the biomass by 70.44%; the diameter class distributions were not reasonable, and forest management should be strengthened to boost the tree growth. The net productivity of the forest was 7.34 t·hm-2 a-1 in average, contributed by the tree story by 4.49 t·hm-2 a-1 and 61.17%, which showed considerably high productivity, while the net productivity of the understory vegetation was rather high, accounting for 38.83% of the total, which indicated the tree Betula luminifera did not make the best of the land capacity. Therefore, forest management should be strengthened to adjust the forest structure and improve net productivity of the tree story.