Photosynthesis ability is one of the factors that affect yield elaboration in cocoa trees. Substantial variability is often seen when measuring gas exchanges in leaves. It is linked to their sampling within the tree and to measurement instability, irrespective of experimental conditions. In order to characterize the factors responsible for such variability, a study was carried out on the island of Espiritu Santo, in Vanuatu (15° latitude south) taking mature leaf samples from different accessible zones in the foliage, corresponding to zones in which gas exchange measurements are carried out.