Assessment of an automated digital method to estimate leaf area index (LAI) in cherry trees

ABSTRACTA study was carried out during two growing seasons to evaluate the performance of a digital photography method to estimate the leaf area index (LAID) of cherry tree cultivars. The trial comprised 10 ‘Bing’ and 10 ‘Sweetheart’ trees where actual leaf area index (LAIA) was obtained by defoliation. Estimations of LAID were obtained by the batch processing of images of the canopy of the same trees which were obtained using a conventional digital RGB camera. Comparisons of LAIA and LAID averages resulted in a good level of agreement for ‘Sweetheart’ for the two growing seasons (percentage of mean absolute error: MAE% = 10.4%). For ‘Bing’, LAID was accurate in the first growing season (MAE% = 17.7%), but underestimated by 44% (MAE%) in the second growing season, presumably due to differences observed in the clumping index and the light extinction coefficient. Results evidenced the robustness of this simple method for determining the leaf area index of cherry trees.