Shadowing is one of the factors that most affects the relation between canopy reflectance and forest light interception efficiency. For Christmas tree plantations, a decreasing exponential function can assess the shadow proportion from canopy SPOT-HRV red or green reflectances. Near-infrared reflectances as well as the wavelength of the inflexion point in the red-edge region (λi) are not affected by shadowing in the canopy. The linear correlation coefficients calculated between the shadow proportion and three common vegetation indices (Normalized Difference Vegetation Index, Perpendicular Vegetation Index and the Transformed Soil Adjusted Vegetation Index) estimated with the SPOT-HRV reflectances are non-significant in the case of PVI and TSAVI (if it is calculated with green reflectances). The limits and possible improvements of such a study are discussed.