*2.2. LiDAR Data Collection*

#### 2.2.1. UAV Laser Scanning Data

The UAV-LiDAR data of the 16 plots were captured on 4 and 5 June 2020, with a Genius UAV LiDAR developed by SureStar, Beijing. The UAV LiDAR area coverage and plot distribution are shown in Figure 2. Each plot at the two sites had a fixed size of 30 m × 30 m. The UAV-LiDAR system consisted of a DJI M200 platform, an R-Fans-16 laser scanner, and an advanced navigation spatial dual-coupled GNSS and IMU sensor. The R-Fans-16 scanner features 16 scan layers with a 30◦ vertical field of view (FOV). It operates at a wavelength of 905 nm and supports 320,000 points per second. The measurement range of R-Fans-16 is 200 m. The flying height for data acquisition was 40 m above ground level with a speed of 5 m/s, resulting in an average point density of approximately 430 pts/m2.
