Vertical distributions of leaf area and inclination angle, and their relationship in a 46-year-old Chamaecyparis obtusa stand
Vertical distributions of leaf area and inclination angle, and their relationship in a 46-year-old Chamaecyparis obtusa stand
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DOI：
10.1016/j.foreco.2005.12.028
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发表时间：
2006-04
影响因子：
3.7
通讯作者：
H. Utsugi;M. Araki;T. Kawasaki;M. Ishizuka
中科院分区：
文献类型：
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作者：
H. Utsugi;M. Araki;T. Kawasaki;M. Ishizuka
对日本中部一处46年生日本柏树林分叶面积和叶倾角的垂直分布进行了研究。通过破坏性抽样（n=9）测量单株叶面积的垂直分布，并拟合到改进的威布尔累积分布函数（Weibull CDF）。Weibull CDF的两个模型参数是通过对树高(H)和全树叶面积的多元回归分析得出的，而全树叶面积是由胸径（DBH）异速导出的。基于这些关系，利用DBH和H数据计算了林分叶面积密度（LAD）在冠层中的垂直分布，得到林分叶面积指数（LAI）为5.77m2m−2。叶子的倾角，“叶子”被定义为附着在主枝上的一簇鳞片叶子，测量了1443片叶子，这些叶子可以从树冠通道脚手架塔上到达。通过冠层的平均叶角（面积加权）为41.6±0.6°，从顶部（55°）到底部（30.3°）呈指数递减。定量分析表明，林冠层平均叶角与林冠层上方向下累积的LAD有密切关系。叶片角（Wg(α)）在冠层的分布呈椭球状，且在冠层高度（10.3 ~ 13.2m、13.3 ~ 16.2m和16.3 ~ 19.3m）各有不同的分布规律。占总LAI 81%的冠层中层形成了Wg（α）的主导格局。这些测量结果表明，叶片倾角与LAD之间的定量关系表征了冠层的光利用率和透光率水平。
The vertical distributions of the leaf area and inclination angle were investigated for a 46-year-old stand of Japanese cypress (Chamaecyparis obtusa Endl.) in central Japan. The vertical distribution of leaf area per tree was measured by destructive sampling (n=9) and fitted to a modified Weibull cumulative distribution function (Weibull CDF). The two model parameters of Weibull CDF were derived from multiple regression analysis of tree height (H) and whole-tree leaf area, which is allometrically derivable from diameter at breast height (DBH). Based on these relationships, the vertical distribution of leaf area density (LAD) through the canopy was computed from DBH and H data, and the stand leaf area index (LAI) was estimated to be 5.77m2m−2. The leaf inclination angle, with a ‘leaf’ defined as a cluster of scale leaves attached to a primary branch, was measured for 1443 leaves that were reachable from a canopy-access scaffold tower. The average leaf angle (area-weighted) through the canopy was 41.6±0.6°, decreasing exponentially from top (>55°) to bottom (30.3°). The quantitative analysis revealed a strong relationship between the average leaf angle in a canopy stratum and the downward cumulative LAD above the stratum. The leaf angle distribution (Wg(α)) through the canopy was ellipsoidal, with different patterns in each of the three canopy layers (10.3–13.2m, 13.3–16.2m and 16.3–19.3m in height). The middle canopy layer, which accounts for 81% of LAI, formed the dominant pattern of Wg(α). These measurements indicate that the level of light utilization and transmittance through the canopy is characterized by the quantitative relationship between leaf inclination angle and LAD.