[目的]研究中亚热带地区的江西省内不同森林类型、林分类型林内倒木的生物量、碳储量及其数量特征分布格局,为该区域森林生态系统功能评估积累基础数据。[方法]以亚热带典型森林133个样地为研究对象,采用实测法对样方内直径≧1 cm,长度≧1 m的倒木逐一测量其中央直径和长度,并记录其分解程度和树种组成。[结果]表明:杉木林和马尾松林倒木生物量和碳储量分别为0.684 t ? hm~(-2),0.279 tc ? hm~(-2)和0.553 t ? hm~(-2)、0.207 tc ? hm~(-2),常绿阔叶林和次生常绿阔叶林分别为11.293 t ? hm~(-2)、4.781 tc ? hm~(-2)和1.888 t ? hm~(-2)、0.812 tc ? hm~(-2),松阔混交林和杉阔混交林分别为1.248 t ? hm~(-2)、0.521 tc ? hm~(-2)和1.28 t ? hm~(-2)、0.432 tc ? hm~(-2);针叶林中Ⅱ、Ⅲ径级倒木生物量较大且与其他两个径级差异显著,针阔混交林中Ⅱ径级倒木与Ⅰ、Ⅲ径级倒木生物著,常绿阔叶林林内Ⅰ径级倒木生物量与Ⅱ、Ⅲ、Ⅳ和Ⅴ径级差异显著。杉木林和马尾松林中度分解倒木生物量最大分别为0.332 t ? hm~(-2)、0.321 t ? hm~(-2),且分别显著大于相应林分类型中的轻度和重度分解倒木;常绿阔叶林表现出同样的变化规律。[结论]中亚热带地区典型针叶林和常绿阔叶林中不同林分类型之间倒木生物量差异显著,而针阔混交林差异不显著。3种森林类型(针叶林、常绿阔叶林和针阔混交林)中不同林分类型之间倒木碳储量差异显著。江两森林倒木主要分布在5~10 cm和10~15 cm的Ⅱ、Ⅲ径级,且主婴处于中度分解等级。针阔混交林(松阔和杉阔)倒木主要分布在海拔700 m以下,常绿阔叶林倒木分布在海拔650 m以上。研究结果表明,常绿阔叶林倒木由于其较大的生物量和碳储量可能会在缓解全球气候变暖和碳循环中扮演重要的作用,且在未来的森林经营和管理中应该重视倒木对森林可持续发展的重要性。
英文摘要:
[Objective] The study aims at investigating the biomass, carbon storage and the quantity distribution of fallen tree within different forest types or stands in Jiangxi Province of mid-subtropics. [ Method] The field survey was carried out, the central diameter and length were measured, and the decay class and species composition of fallen tree (diameter ≧ 1 cm,length ≧ 1 m) within 133 plots in subtropical typical forests were recorded. [Result] The biomass and carbon storage in Cunninghamia lanceolata forests were 0.684 t ? hm~(-2) and 0.279 tc ? hm~(-2), while that in Pinus massoniana forests were 0.553 t ? hm~(-2) and 0.207 tc ? hm~(-2). However, the biomass and carbon storage in evergreen broadleaf forests were 1.248 t ? hm~(-2) and 0.521 tc ? hm~(-2), and in secondary evergreen broadleaf forests were 1.888 t ? hm~(-2) and 0.812 tc ? hm~(-2). The biomass and carbon storage in P. massoniana-broadleaf mixed forests were 1.248 t ? hm~(-2) and 0.521 tc ? hm~(-2),while in C. lanceolata-broadleaf forests were 1 ? 280 t ? hm~(-2) and 0.432 tc ? hm~(-2); the fallen tree biomass of diameter class Ⅱ and Ⅲ were relatively larger than the others,which were significantly different from other diameter class in coniferous forests, there were significant differences between fallen tree biomass of diameter Ⅱ and Ⅰ,Ⅲ in coniferous-broadleaf mixed forests,while the fallen tree biomass of diameter class I was significantly different from Ⅱ, Ⅲ, Ⅳ and Ⅴ. The moderate decays of fallen tree of C. lanceolata and P. massoniana were at 0.332 t ? hm~(-2) and 0.321 t ? hm~(-2),which was higher than those in mild and severe decay of fallen tree. The decay of fallen tree in evergreen broadleaf forest was similar to C. lanceolata and P. massoniana. [ Conclusion] These indicated that the biomass of fallen tree within different coniferous and evergreen broadleaf forests was significantly varied, while no significant difference was found with different coniferous-broadleaf forests in mid-subtropics. The carbon storage of fallen tree within different coniferous, evergreen broadleaf and coniferous-broadleaf forests were significantly different. The fallen trees in Jiangxi mainly dominated by diameter class Ⅱ(5~10cm) and Ⅲ (10 ~15 cm), and most were in moderate decay. The fallen tree of coniferous-broadleaf forests was primary distributed below 700 m a. s. 1, while the fallen tree of evergreen broadleaf forests was mainly distributed above 650 m a. s.1. The results suggested that the fallen tree may play a key role in mitigating global warming and carbon cycles because of the larger amount of biomass and carbon storage in evergreen broadleaf forests. It is necessary to pay more attention to the influence of fallen tree on sustainable development of forests in the future' s operation and management.