马尾松天然次生林生物量的结构与分布

Study on the biomass structure and distribution of natural secondary forest of Pinus massoniana

对位于重庆铁山坪的46年生马尾松天然次生林的生物量结构与分布特征及生产力的研究结果表明，林分的初级生产力为8．34t／（hm^2·a），生物量为146．08t／hm^2，其中各层次的生物量分配顺序为：乔木层（87．43％）〉枯枝落叶层（5．65％）〉下木层（5．46％）〉草本层（1．46％）。乔木层的生物量为127．72t／hm^2，其中各器官生物量比例的顺序是：树干（72．82％）〉树枝（11．19％）〉树根（9．27％）〉树皮（4．43％）〉针叶（2．29％）。在林分的各器官生物量的垂直结构方面，10m以下树干生物量占其总量的81．13％；树枝的生物量主要集中在12～16m，占其总量的82．25％；针叶的生物量主要集中在12～18m，其中1年生针叶占其总量的93．25％；根系生物量主要集中在距地表深40cm的土层内，占其总量的76．45％。当前，该林分生产力低，群落结构不合理，应对该种类型的森林群落进行林相改造，调整乔木层产量结构，以提高群落的综合效应。

The study on the structure and distribution character of biomass of a 46 - year - old natural secondary forest of Pinus massoniana in Chongqing and its productivity shows, that the primary productivity of the forest ecosystem is 8.34 t/（hm^2·a）. The biomass is 146.08 t/hm^2, the distributing sequence of the biomass of the forest ecosystem is： tree stratum （87.43%）〉humus layer （5.65%） 〉undergrowth （5.46%） 〉herb （1.46%）. The biomass of the tree layer is 127.72 t/hm^2 and biomass distributing sequence of different organs is： trunk （72.82%） 〉 branch （11.19%） 〉root （9.27%） 〉bark （4.43%） 〉needle （2.29%）. Regarding the vertical structure of biomass of each type of organ, the biomass of trunks under the height of 10m accounts to 81.13% of its total; the biomass of branches between 12 m and 16m accounts to 82.25% of its total; the biomass of one - year- old needles between 12 m and 18m accounts to 93.25% of its total; and the biomass of roots in the soil layer of 0 - 40 cm accounts to 76.45 %. The present stage productivity of the community is lower and its structure is irrational. The forest - type of the forest community and productivity structure of tree layer should be regulated so as to improve the integrate effects of the community.