Terrestrial Laser Scanning as an Effective Tool to Retrieve Tree Level Height, Crown Width, and Stem Diameter
Terrestrial Laser Scanning as an Effective Tool to Retrieve Tree Level Height, Crown Width, and Stem Diameter
复制标题
DOI：
10.3390/rs70201877
复制
发表时间：
2015-02
期刊：
影响因子：
--
通讯作者：
Shruthi Srinivasan;S. Popescu;Marian Eriksson;R. Sheridan;N. Ku
中科院分区：
文献类型：
--
作者：
Shruthi Srinivasan;S. Popescu;Marian Eriksson;R. Sheridan;N. Ku
森林结构参数的准确测量对于森林清查和生长模型、野火管理以及碳循环建模至关重要。地面激光扫描（TLS）通过非破坏性的方法提供准确的树冠下信息，填补了树木尺度人工测量和大规模机载激光雷达测量之间的空白。本研究开发了一种创新的方法来提取东德克萨斯州树木的单株树高、胸径（DBH）和冠宽。此外，还研究了扫描设置（如开叶/落叶季节、树木与扫描仪的距离以及处理选择）对获得树木测量值准确性的影响。采用不同高度筒体拟合的方法反演胸径。从TLS点云中提取单株树，确定树高和树冠宽度。采用不同方法对实测胸径与TLS计算的胸径进行验证，r²值在0.91 ~ 0.97之间。预测树高的准确率为92% （RMSE = 1.51 m）。当使用现场测量冠宽验证TLS衍生冠宽时，r平方值为0.84，RMSE为1.08 m。本研究还讨论了由于树木遮蔽而低估实地测量森林结构参数的例子。这项研究的结果将有利于林业工作者和机载和星载平台的遥感研究，用于地图升级或校准目的，用于地上生物量估计，以及森林管理部门的审慎决策。
Accurate measures of forest structural parameters are essential to forest inventory and growth models, managing wildfires, and modeling of carbon cycle. Terrestrial laser scanning (TLS) fills the gap between tree scale manual measurements and large scale airborne LiDAR measurements by providing accurate below crown information through non-destructive methods. This study developed innovative methods to extract individual tree height, diameter at breast height (DBH), and crown width of trees in East Texas. Further, the influence of scan settings, such as leaf-on/leaf-off seasons, tree distance from the scanner, and processing choices, on the accuracy of deriving tree measurements were also investigated. DBH was retrieved by cylinder fitting at different height bins. Individual trees were extracted from the TLS point cloud to determine tree heights and crown widths. The R-squared value ranged from 0.91 to 0.97 when field measured DBH was validated against TLS derived DBH using different methods. An accuracy of 92% (RMSE = 1.51 m) was obtained for predicting tree heights. The R-squared value was 0.84 and RMSE was 1.08 m when TLS derived crown widths were validated using field measured crown widths. Examples of underestimations of field measured forest structural parameters due to tree shadowing have also been discussed in this study. The results from this study will benefit foresters and remote sensing studies from airborne and spaceborne platforms, for map upscaling or calibration purposes, for aboveground biomass estimation, and prudent decision making by the forest management.