机载激光雷达亚热带森林乔木层垂直结构分类方法  

Classification of Vertical Forest Structure of Overstory in Subtropical Forests Using Airborne Lidar Data

作　　者：周相贝 李春干[1] 余铸 陈中超 苏凯 ZHOU Xiangbei;LI Chungan;YU Zhu;CHEN Zhongchao;SU Kai(Forestry College of Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学林学院,南宁530004

出　　处：《林业资源管理》2022年第1期106-113,共8页Forest Resources Management

基　　金：广西林业科技推广示范项目(GL2020KT02);广西壮族自治区林业勘测设计院科研业务费项目(GXLKYKJ201601)。

摘　　要：森林垂直结构分类具有重要的生态学和林学意义。以广西为研究区,通过10阶多项式对样地的离散机载激光点云的高度—覆盖度频率分布进行拟合,得到反映冠层物质垂直分布的垂直冠层剖面(伪波),通过伪波提取有效峰、冠层表面高、层下高、林层高与冠层表面高比值等冠层结构参数,建立分类规则,将林分乔木层垂直结构分为6个类型,采用混淆矩阵评估分类精度,并选取一个面积为1369km^(2)的区域进行制图以检验分类规则的可推广性。结果表明:1)1147个样地的总体分类精度为93.9%,Kappa系数为0.913;2)单峰、双峰、3峰剖面的分类错误率为6.2%,7.4%和9.1%,杉木林、松树林、桉树林和阔叶林的分类错误率分别为9%,6.4%,2.4%和6.9%,说明林分垂直结构越复杂分类精度越低;3)各个林层的检测精度均高于96%,漏检率均小于4%,误检率均小于10%,表明各个林层都能够得到准确的检测;4)制图区域的分类规则的覆盖率达到99.8%。研究表明,乔木层垂直结构分类方法具有分类精度高、普适性强、可推广性好、空间信息丰富的特点,适用于大区域亚热带森林乔木层垂直结构分类制图。The vertical structure classification of forest plays an important role in ecology and forestry.A vertical canopy profile(pseudo-wave)was obtained by fitting the frequency distribution of height and coverage of discrete laser point cloud in Guangxi by using the tenth order polynomial method,which reflected the vertical distribution of canopy material.Canopy structure parameters such as effective peak,stand surface height,sub-storey height,and crown ratio were extracted by pseudo-wave and classification rules were established to divide the vertical structure of stands into six types.Confusion matrix was used to evaluate the classification accuracy,and an area of 1369km^(2) was selected for mapping to test the generalization of classification rules.The results showed that:1)In the classification results of 1147 sample plots,the overall classification accuracy was 93.9%,and the Kappa coefficient was 0.913;2)The error rates of single-peak,double-peak and triple-peak were 6.2%,7.4%and 9.1%respectively,while the error rates of Chinese fir forest,pine forest,eucalyptus forest and broadleaved forest were 9%,6.4%,2.4%and 6.9%,respectively,indicating that the more complex the vertical structure of the stand,the lower the accuracy of classification;3)The accuracy of each forest layer was higher than 96%,the omission errors were less than 4%,and the commission errors were less than 10%,indicating that each forest layer can be accurately detected;4)The coverage of classification rules in mapping areas reached 99.8%.In this study,vertical forest classification method with high accuracy,good generalization and rich spatial information is suitable for overstory vertical structure classification mapping of large regional subtropical forest.

关 键 词：连续冠层垂直剖面 伪波 冠层结构参数 混淆矩阵 

分 类 号：S771.8[农业科学—森林工程]