Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China
Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China
复制标题
林分结构多样性而非物种多样性增强了中国东部次生亚热带森林的地上碳储存
DOI：
10.5194/bg-13-4627-2016
复制
发表时间：
2016-08-17
期刊：
影响因子：
4.9
通讯作者：
Xu, Ming-Shan
中科院分区：
文献类型：
--
作者：
Ali, Arshad;Yan, En-Rong;Xu, Ming-Shan
林分结构多样性是影响林分地上部分碳储量的重要因素，其主要表现为胸径和总高的差异。然而，很少有研究考虑了天然林地上碳储量与林分年龄，林分结构多样性和物种多样性的多元关系。本研究测定了中国东部80个亚热带森林样地的地上碳储量、林龄、树种、胸径和高度多样性指数。我们采用结构方程模型（SEM）测试的直接和间接影响林分结构多样性，物种多样性，林分年龄对地上碳储量。物种多样性和林分结构多样性之间的路径具有不同方向的三个最终SEM与数据的拟合优度相似。它们解释了地上碳储量变异的82%，解释了林分结构多样性变异的55-59%，解释了物种多样性变异的0.1 - 9%。林分年龄表现出强烈的正总效应，包括积极的直接效应（β = 0.41），并通过林分结构多样性（β = 0.41）对地上碳储量的正间接效应。林分结构多样性有积极的直接影响，地上碳储量（β = 0.56），而有一个负的直接关联，但有一个积极的间接影响，通过林分结构多样性，地上碳储量的物种多样性的总影响不大。在研究中的森林地上C存储的物种多样性的总影响可以忽略不计可能是由于竞争性排斥与高地上生物量，或历史记录的生产性物种的偏好。分析表明，林分结构多样性是中国东部亚热带次生林地上碳储量变化的主要决定因素。因此，通过营林作业维持树木胸径和高度的多样性可能是提高这些森林地上碳储量的有效途径。
Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern China. We employed structural equation modelling (SEM) to test for the direct and indirect effects of stand structural diversity, species diversity, and stand age on aboveground C storage. The three final SEMs with different directions for the path between species diversity and stand structural diversity had a similar goodness of fit to the data. They accounted for 82% of the variation in aboveground C storage, 55-59% of the variation in stand structural diversity, and 0.1 to 9% of the variation in species diversity. Stand age demonstrated strong positive total effects, including a positive direct effect (beta = 0.41), and a positive indirect effect via stand structural diversity (beta = 0.41) on aboveground C storage. Stand structural diversity had a positive direct effect on aboveground C storage (beta = 0.56), whereas there was little total effect of species diversity as it had a negative direct association with, but had a positive indirect effect, via stand structural diversity, on aboveground C storage. The negligible total effect of species diversity on aboveground C storage in the forests under study may have been attributable to competitive exclusion with high aboveground biomass, or a historical logging preference for productive species. Our analyses suggested that stand structural diversity was a major determinant for variations in aboveground C storage in the secondary subtropical forests in Eastern China. Hence, maintaining tree DBH and height diversity through silvicultural operations might constitute an effective approach for enhancing aboveground C storage in these forests.