Direct measurement of the three-dimensional distribution of leaf area density and light conditions in a mature oak stand by the cube method  

作　　者：Chiharu Migita Yukihiro Chiba Tanaka Kenzo 

机构地区：[1]Forestry and Forest Products Research Institute,Tsukuba,Ibaraki 305-8687,Japan [2]Japan International Research Centre for Agricultural Sciences,Tsukuba,Ibaraki 305-8686,Japan

出　　处：《Journal of Forestry Research》2023年第6期1817-1827,共11页林业研究（英文版）

基　　金：partly supported by Grant-in-Aid for scientific research(No.17658070,22580173)from the Ministry of Education,Science and Culture,Japan;“Evaluation of genetic resources for strengthening productivity and adaptability of tropical forests”from the Japan International Research Centre for Agricultural Sciences。

摘　　要：Although the distributions of foliage and light play major roles in various forest functions,accurate,nondestructive measurement of these distributions is difficult due to the complexity of the canopy structure.To evaluate the foliage and light distributions directly and nondestructively in a mature oak stand,we used the cube method by dividing the forest canopy into small cubes(50 cm per side)and directly measured leaf area density(LAD,the total one-sided leaf area per unit volume,i.e.,cube)and relative irradiance(RI)within each cube.The distribution of LAD and of RI was highly heterogeneous,even at the same canopy height.This heterogeneity reflected the presence of foliage clusters associated with multiple forking branches.The relationship between cumulative LAD at the canopy surface and average RI followed the Beer-Lambert law.The mean light extinction coefficient(K)was 0.32.However,K was overestimated by more than double(0.80)when calculated based on the classical method using RI at the forest floor.This overestimation was caused by the lower RI due to light absorption by nonleaf plant parts below the canopy.Our findings on the complex foliage and light distributions in canopy layers should help improve the accuracy of RI and K measurements and thus more accurate predictions of environmental responses and forest functions.

关 键 词：Beer-Lambert law Canopy structure Foliage cluster Leaf area density Leaf area index Relative light intensity 

分 类 号：S794.9[农业科学—林木遗传育种]