Canopy structure is a key variable in determining the adap-tive potential of forages and influences the radiation use efficiency (RUE) under different light conditions. The light extinction coefficient calculated from the Beer-Lambert formula (k) shows the canopy architecture and light inter-ception patterns of plants and thus their potential ability to convert light energy (photosynthetically active radiation, PAR) into plant biomass (Hirose 2005). Under shade, for-ages may experience changes in plant morphology and canopy structure. Many authors have reported those changes and related them to modifications in light quantity and quality (Varella et al. 2011). The magnitude of these morphological changes may be a determinant in screening forages for shaded environments such as in silvopastoral systems. The objective of this study was to determine the light interception patterns and extinction coefficients of