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

林冠内树叶的空间分布是林分结构的一个重要方面，它决定着林分内的小气候、森林生态系统的气体交换和树干形状。随着叶簇的形成，叶的分布不连续，叶密度在冠层内分布不均。冠层内的簇形成和缝隙镶嵌增强了冠层结构的异质性。尽管它很重要，但由于很难在高大树木的林分中进行测量，因此关于三维树叶分布格局的定量信息很少。对叶簇的结构还缺乏定量的了解。本研究的目的是量化树叶分布的异质性，阐明树种和林分阶段间树叶结构的复杂性是否发生变化，以及了解树叶分布的异质性对森林生态系统气体交换的影响。I Quant…进一步阐明了日本锦鸡儿树冠内叶片的簇状结构，并考察了随着年龄的增长，该物种树冠内叶片的分布是否更加不均匀和丛生。老冠(78年和88年)比年轻冠(20年)和中年冠(40年)具有更多的异质性和碎片化的叶簇。随着年龄的增长，树叶的分布也越来越多。这些异质性与树冠内的林隙比例密切相关。通过测量树冠内叶片的三维分布，比较了两种常绿阔叶树冠冠层树种锥栗和红楠的叶簇结构。尖顶锦鸡儿形成了致密的集群，这可能是由于其枝条结构所致。我们测量了水青冈树冠内的三维叶片分布。利用树冠叶片分布参数估算树冠内光强的时空变化，建立了单株树木蒸腾和光合作用的预测模型。林隙镶嵌结构是影响林冠结构复杂性的重要因素之一。构建了林隙花叶结构对幼苗光合作用影响的模型。林隙嵌合体对光合势和幼苗生态位的空间分布有较大影响。较少

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