Modeling the view-angle dependence of the gap fraction in subtropical forests by using terrestrial laser scanning

•The DGF at arbitrary view angles can be obtained from TLS data.•A power function models the relationship between nadir- and non-nadir-oriented DGF.•Sloped terrain weakens the dependence of DGF on the VZA.•Low density, low tree height, and small crown diameter strengthen the dependence.•VAA is as important as VZA in DGF estimation for forests on sloped terrain.