基于相邻木关系的林分微观结构特征的研究

Although individual distribution pattern on different scales has been achieved, further research on stand microstructure is conducive to mining and evaluating the biological diversity and to solving key problems such as the choice of cutting wood in continuous cover forest and species configuration in silviculture. Stand structure is the basis of forest structure research. There are a great number of structural elements that often maintain close links to each other can be quantified on stand level, however, they could only describe the single aspect or overall characteristics of a stand (i.e., macrostructure). That is to say, they cannot simultaneously provide any information about two or more sides of stand structure. If two or more elements were simultaneously used to depict the feature of forest stand, then its microstructure could be well displayed. Therefore, this contribution attempts to classify the current analyzing method, search for the potentially joint indicators and propose two microstructure analysis methods—the bivariate distribution of structural parameters and the trivariate distribution of structural parameters. Five standard fixed plots in three types of Pinus Yunanensis var. Tenuifolia forest in Yachang National Orchidaceae nature reserve Guangxi province, will be established and measured to validate its ability in analyzing different levels of tree structure. These new methods will provide the fundamental theory for reasonable protection and utilization of forest resources.

尽管目前已经解决了不同空间尺度上林木个体的分布格局，但进一步研究林分微观结构无论是对生物多样性的挖掘与评估，还是对解决营林中树种配置、恒续林经营中采伐木的选择等等都具有十分重要的意义。林分结构是研究森林结构的基础，林分水平已经有大量的分析方法，但它们均只能描述单方面或整体的宏观结构特征。若同时从两个或以上方面分析林分就有可能反应林分的微观结构。为此，本研究试图对当前林分结构分析方法进行系统分类，搜寻满足概率联合的指标，并试图提出分析林分微观结构的新方法——结构参数二元分布和结构参数三元分布。拟在广西雅长兰科植物国家自然保护区建立数块不同类型天然林样地，验证这两种新方法分析不同水平层次林木结构的能力，为森林资源的合理保护和利用提供理论依据。

本研究归纳传统森林群落结构分析方法，发现它们仅能够提供林分或者某个树种的整体特征，而无法提供林分内具有某类共同特征的林木的生境特征，同时结果表达式常常是单值。我们利用基于最近相邻木空间关系的一组林分空间结构参数（角尺度、混交度和大小比数）在表达上的频率优势，结合统计学原理创造性提出林分空间结构参数二元法和三元法，并用4块试验样地数据对其验证和解读，证实了这2种方法有很强的解析林分微观结构能力。我们建立的5块固定样地不仅为本研究提供了基础数据，也将成为监测和了解我国西南地区次生林发展动态的重要基地，为次生林近自然经营和保护提供参考依据。