The Canopy Semi-analytic Pgap And Radiative Transfer (CanSPART) model: Formulation and application

► Developed semi-analytic multi-layer model to predict gap probability and radiation transfer in clumped canopies. ► Analytic approximation to the crown porosity: computationally efficient and demonstrated validity. ► Applied to complex canopy structures. ► Can be formulated in terms of a clumping factor: single clumping factor shown to perform well compared to height- and angle-resolved clumping factor. ► Results agree well with site observations of albedo, provided the effect of clumping on scattered radiation interception is included.