Evaluation of heterogeneity in foliage distribution. How does the complexity of canopy structure affect on the gas-exchanges of forest ecosystem?

林冠中树叶的空间分布是营林分结构的一个重要方面，它决定着林分的小气候、森林生态系统的气体交换和树干的形状。叶群结构呈不连续分布，叶密度不均匀。林冠内的丛簇形成和林窗镶嵌增强了林冠结构的异质性。尽管它的重要性，很少有定量信息的三维树叶分布格局是可用的，因为很难在高大的树木的立场进行测量。叶簇的结构在数量上知之甚少。本研究旨在量化植物叶片分布的异质性，阐明植物叶片结构的复杂性是否随树种和林分阶段而变化，以及植物叶片分布的异质性对森林生态系统气体交换的影响.我定量 ...更多信息 明确了冠内叶的簇状结构。japonica，并研究了该种冠内叶片是否随年龄的增长而分布更不均匀和丛生。老冠（78岁和88岁）有更多的异质性和破碎的叶簇比年轻（20岁）和中年冠（40岁）。随着年龄的增长，叶片分布增多。这些异质性与树冠内的差距比例密切相关.通过测定叶在冠层内的三维分布，比较了两种万年青阔叶林冠层乔木--东北锥（Castanopsis cuspidata）和红楠（Machilus thunbernalus）的叶簇结构。尖叶锦鸡儿形成紧密的簇群，这可能与其枝条结构有关.我们测量了毛茛树冠内的三维叶片分布。利用叶片分布参数估算树冠内光照的时空变化，建立了单株蒸腾速率和光合速率的预测模型.林隙镶嵌结构是影响林冠复杂性的重要因素之一。构建了林窗镶嵌结构对幼苗光合速率影响的模型。林隙镶嵌对光合势的空间分布和幼苗生态位有较大影响。少

The spatial distribution of foliage in canopy represents an important aspect of the stand structure for silviculture, with determining the microclimates in the stand, gas-exchanges of forest ecosystems, and the stem shape. Foliage distributed discontinuously with constructing foliage cluster, and the foliage density is heterogeneous in canopy. The cluster formation and gap mosaics in the canopy enhance the heterogeneity of canopy structures. In spite of its importance, little quantitative information on three-dimensional foliage distribution pattern was available, because of the difficulty in making measurements in stands of tall trees. The structure of foliage cluster is poorly understood quantitatively. This study project aims to quantify the heterogeneity of foliage distribution, to clarify whether the complexity of foliage structure changes among species and stand stages, and to know the impact of heterogeneity of foliage distribution on gas-exchanges of forest ecosystem.1. I quant … More ified the cluster structure of foliage within crown of C. japonica, and examined whether foliages within crowns of this species distribute more heterogeneous and clumpy with ageing. Old crowns (78yrs and 88yrs) had more heterogeneous and fragmented foliage clusters than young (20-yrs) and middle-aged crowns (40yrs) did. Foliage distributed more with ageing. These heterogeneities closely related to the gap proportion within a crown.2. The structures of foliage clusters were compared between two evergreen broadleaved canopy trees ; Castanopsis cuspidata and Machilus thunbergii, through measuring three-dimensional distribution of foliages within crowns. C.cuspidata formed compact clusters, possibly due to its shoot architectures.3. We measured three-dimensional foliage distribution within crowns of Fagus crenata. A model for predicting transpiration and photosynthetic rate of single tree was constructed through evaluating temporal and spatial light variance in a crown using parameters of foliage distribution.4. Gap mosaic structure is one of important factor of complexity of canopy. I constructed a model for estimating the effect of gap mosaic structure on photosynthetic rates of seedlings. Gap mosaics had large impacts on spatial distribution of photosynthetic potential, and niches of seedlings. Less