Evaluating the use of Beer's law for estimating light interception in canopy architectures with varying heterogeneity and anisotropy

•Errors in Beer's law due to canopy heterogeneity and anisotropy were evaluated.•As plant spacing approached the canopy height, errors became significant.•Heterogeneity caused errors in daily light interception of up to 115%.•Errors due to anisotropy were usually small except for in the vineyard case.