Table 7 Existing significant differences between single canopy gap character class to all other four classes in laser metrics of z value (z) and intensity value (i) in different predefined height classes (<0.3, 0.3–5, and >5 m) and laser echo types (A = “all,” F = “first of many,” L = “last of many,” and O = “only” echoes)

DDW

z

z

i

zi

z

z

VEGE

z

zi

z

zi

z

z

UNDER

i

zi

zi

i

z

z

i

i

NO_UNDER

i

z

i

z

zi

z

OTHERS

i

z

z