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Evaluation of CO2-fixation capacity in Sugi (Cryptomeria japonica) canopy

杉树冠层二氧化碳固定能力评估

基本信息

批准号：
10460066
负责人：
GYOKUSEN Koichiro
金额：
$ 3.52万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

To reveal the CO2-fixation capacity of Sugi (Cryptomeria japonica D.Don) canopy, (1) branch structure which determine the leaf distribution, (2) leaf nitrogen distributin in a crown which determine the leaf productivity were investiqated.(1) branch structureBranch density and branch distribution in an individual sugi crown were determined hereditarily, and these branch characteristics can be used as parameters of crown structure model.The branches attached at the upper and middle parts of a crown had the space spreading function and the lower branches had the spcace filling function.Thinning had not affected the crown shape, but leaf mass and their distribution had changed. We concluded that thinning has an effect on leaf productivity by changing leaf mass and their position.The growth of stem and branch had decreased after pruning. The decreasing rate of branch growth was smaller than that of shoot, then the crown shape had changed to an umbrella type. This phenomena can be explained as a rearrangement of leaves for the compensation of photosynthetic organ loss.(2) Leaf nitrogen distributionNitrogen content of a current year leaves decreased according to light intensity decrease, then nitrogen content of upper crown was high and that of lower crown was low. Nitrogen content of old leaves was low and constant.The effect of growing site on leaf nitrogen content was investigated. Leaf nitrogen content in a crown was under the control of two parameters, namely, light intensity and site index. These two parameters can be used as main factors affecting leaf nitrogen content in a crown.A model for estimating CO2-fixation of a Sugi canopy was constructed using leaf nitorogen distribution and leaf photosynthesis parameters. This model was applied to a some sugi stand and the calculation result was sufficiant for explaining the stand's data.

为了揭示杉木（Cryptomeria japonica d.d don）冠层固定co2的能力，研究了杉木（Cryptomeria japonica d.d don）冠层结构对叶片分布的影响，研究了杉木冠层中叶片氮的分布对叶片生产力的影响。(1)分支结构杉木单株树冠的分支密度和分支分布是遗传决定的，这些分支特征可以作为树冠结构模型的参数。树冠上部和中部附着的枝条具有空间扩张功能，下部附着的枝条具有空间填充功能。间伐对冠形没有影响，但叶片质量和分布发生了变化。结果表明，间伐通过改变叶片质量和位置对叶片生产力产生影响。修剪后茎和枝的生长均有所下降。枝条生长的下降速率小于新梢生长的下降速率，此时树冠形状已转变为伞形。这种现象可以解释为叶片的重新排列，以补偿光合器官的损失。(2)叶片含氮量随光照强度的降低而降低，呈现上冠高、下冠低的趋势。老叶含氮量低且稳定。研究了不同生长地点对叶片氮含量的影响。树冠叶片氮含量受光照强度和立地指数两个参数的控制。这两个参数可以作为影响冠部叶片氮含量的主要因素。利用叶片氮素分布和叶片光合参数，建立了杉木冠层固co2模型。将该模型应用于某杉木林分，计算结果足以解释林分数据。