Table 1. Statistical table of sample size at different research scales.

Scale of study	Sensor type	Number of samples	Sample proportion (%)	I2 (%)
Tree	UAV lidar	38	19.90	97.6
	Ground lidar	42	21.99	75.8
	RGB	24	12.57	95.8
	Spectra	4	2.09	72.7
Plot	UAV lidar	31	16.23	97.0
	Ground lidar	7	3.66	73.5
	RGB	13	6.81	59.5
	Spectra	12	6.28	68.3
Stand	UAV lidar	13	6.81	86.6
	Ground lidar	2	1.05	88.3
	RGB	3	1.57	0.0
	Spectra	2	1.05	90.8
Total		191	100