中亚热带北部森林生态系统生物量估算与储存机制研究

发布时间：2018-05-21 07:03

  本文选题：亚热带 + 生物量　； 参考：《中国科学院研究生院(武汉植物园)》2016年博士论文

【摘要】：本文以中亚热带北部森林为研究对象,以获取的解析木、湖南八大公山25公顷监测样地和湖北森林107个样地调查数据为基础,运用了层次贝叶斯、结构方程模型等技术手段,研究了群落尺度上的生物量估算模型构建、现状、分布、驱动机制以及个体水平的碳分配策略和与物种多样性的关系,目的在于探讨亚热带森林的碳在个体、群落和生态系统内的分布和储存机制。本文主要结论如下：1.通过147棵树的地上部分和23个根部构建局域生物量估算模型,在原有模型基础上,我们添加了木材密度和冠幅并检验其作用,发现木材密度能够改进模型而冠幅却不能。另外,我们用本实验数据去验证其他亚热带模型的预测能力,发现大多数模型对于本数据的预测质量都不好,但是模型中有树高变量的比只有胸径模型预测要稳定些。基于此,我们建立一套中亚热带北部常绿落叶阔叶混交林地上和地下生物量模型。2.根据已经建好的模型,估算了湖南八大公山25 ha样地生物量,发现20x20m样方尺度上的生物量平均值是252.7±108.7 Mg/ha。通过空间插值的方法,绘制了森林生物量空间分布图,发现生物量呈斑块化分布,且与地形有较强的相关。同时,我们也发现大树密度可以解释71%的生物量变异,依此,我们应用方差分割发现,地形、空间和生物因子可以解释约64.8%的生物量变异。通过选择函数发现,地形因子中的凹凸度和地形湿度指数以及生物因子中的树密度和个体密度为驱动因子,生物量与凹凸度、树密度和木材密度正相关,与地形湿度指数负相关。影响大树分布的环境因子与生物量相同,只是解释度和相关关系有所差异。3.利用亚热带59个物种的树结构数据,应用层次贝叶斯方法,检验树结构(H-D, H-F, H-W1)在种内、种间和功能群的差异,发现群落水平上的树结构表现出一定的收敛,大部分的物种没有表现出种间差异。通过Kendall秩相关分析树结构随上限径级和光的需求能力在个体生长阶段的变化,发现高大物种有较纤细的树干,在小径级有较浅和窄的树冠,在大径级有较宽和深的树冠；需光物种在在林冠上有较纤细的树干,在中等径级有较宽的树冠。4.利用中亚热带107个森林样地调查数据和土壤、地形、林龄数据,研究了亚热带物种多样性与森林生态系统关系及其驱动机制。发现物种多样性和森林生物量在亚热带是呈现积极的正相关,林龄和海拔与物种多样性和生物量呈现正相关,土壤因子与多样性负相关而与生物量正相关。当加入大树密度后,物种多样性与森林生物量关系从正相关变为负相关,通过比较大树的光需求值,发现这些大树大都是需光物种。因而物种通过大树来进行资源互补来影响森林生态系统功能,而这些大树都是需光物种则表明有较强的选择效应。
[Abstract]:Taking the forest in the northern part of the middle subtropics as the research object, taking the obtained analytic wood, 25 ha monitoring sample land in Badgongshan, Hunan Province and 107 sample plots of Hubei forest as the basis of the investigation data, this paper uses hierarchical Bayes, structural equation model and other technical means. In this paper, biomass estimation models on community scale, current situation, distribution, driving mechanism, individual level carbon allocation strategies and their relationship with species diversity are studied. The purpose of this study is to explore the individual carbon content of subtropical forests. Distribution and storage mechanisms in communities and ecosystems. The main conclusions of this paper are as follows: 1. Based on the local biomass estimation model of the aboveground parts and 23 roots of 147 trees, the wood density and crown width were added and tested. It was found that the wood density could improve the model, but the crown width could not. In addition, we use the experimental data to verify the prediction ability of other subtropical models. It is found that most of the models have poor prediction quality for this data, but the model with tree height variables is more stable than the DBH model. Based on this, we establish a model of aboveground and underground biomass of evergreen deciduous broad-leaved mixed forest in the north of central subtropics. Based on the established model, the biomass of 25 ha plot in Badagong Mountain, Hunan Province was estimated. It was found that the average biomass on the scale of 20x20m was 252.7 卤108.7 mg / ha. The spatial distribution map of forest biomass was plotted by spatial interpolation. It was found that the biomass was patch distributed and had strong correlation with terrain. At the same time, we also found that tree density can account for 71% of the biomass variation. Based on this, we found that terrain, space and biological factors can account for about 64.8% of the biomass variation. Through the selection function, it is found that the concave convexity and topographic humidity index in topographic factors and the tree density and individual density in biological factors are driving factors, and the biomass is positively correlated with concavity, tree density and wood density. It is negatively correlated with topographic humidity index. The environmental factors affecting tree distribution were the same as biomass, but the degree of interpretation and correlation were different. 3. Using tree structure data of 59 subtropical species and using hierarchical Bayes method, the differences of tree structure within species, between species and functional groups were examined. It was found that the tree structure at community level showed a certain convergence. Most species do not show interspecific differences. By Kendall rank correlation analysis, it was found that tall species had slender trunks, shallower and narrower crowns, and wider and deeper crowns at large diameter levels. Light species have slender trunks on the canopy and a wider crown. 4 at the middle diameter level. The relationship between species diversity in subtropics and forest ecosystem and its driving mechanism were studied by using the survey data of 107 forest plots in the middle subtropics and the data of soil, topography and forest age. It was found that species diversity was positively correlated with forest biomass in subtropics, forest age and altitude were positively correlated with species diversity and biomass, soil factors were negatively correlated with diversity but positively correlated with biomass. When tree density was added, the relationship between species diversity and forest biomass changed from positive correlation to negative correlation. By comparing the light demand values of big trees, it was found that most of these trees were light-demanding species. As a result, species complement each other to influence forest ecosystem function, and these big trees are light-demanding species, which indicate that they have strong selective effect.
【学位授予单位】：中国科学院研究生院(武汉植物园)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S718.5
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本文编号：1918221