3D Radiative Transfer Modelling of Forest Canopies Reconstructed from Terrestrial Laser Scanning: A Case of Tall Australian Eucalypts

In this study, we demonstrated feasibility of a full three-dimensional (3D) reconstruction of a spatially and structurally heterogeneous forest stand of tall Australian eucalypt trees from terrestrial laser scanning (TLS) of individual trees. We provide a direct validation of the Discrete Anisotropic Radiative Transfer (DART) model bidirectional Monte Carlo path tracing (DART-Lux) by comparing a drone-based hyperspectral acquisition of the studied forest with a corresponding DART forward simulation. Finally, we successfully retrieved from a drone hyperspectral imagery contents of leaf chlorophylls a+b (Cab), total carotenoids (Ccar), and anthocyanins (Cant) for sunlit parts of the eucalypt canopy with random forest regressions trained on 2268 spectral simulations of the study site carried out in coupled Fluspect-Cx and DART models.