这是因为影像点云对单木及林分的中下层结构特征不能很好的体现，而水杉的单

This is because the underlying structural features video-on-one point cloud and wooden stands not well represented, and Metasequoia single wooden structure than regular Poplar, Poplar crown more branches, so the face of poplar relatively complex crown structure, the accuracy is lower than the fir tree splitting unit [31]

This is because the image point cloud on the single wood and forest sub-structure characteristics can not be very good embodiment, and the water fir single-wood structure than the poplar tree regulation, poplar canopy branch more, so in the face of the relatively complex tree canopy structure, the accuracy of single wood division is lower than the water fir .

This is because the image point cloud can not well reflect the structural characteristics of single wood and the middle and lower layers of the stand, while the single wood structure of Metasequoia is more regular than that of poplar, and the crown branches of poplar are more, so the accuracy of single wood segmentation is lower than that of Metasequoia when facing the relatively complex crown structure of poplar [31]<br>