Nuts may be poorly filled in seasons with favorable conditions to attain a good nut size. The condition of leaves, because to produce well-filled nuts, the trees must bear a large leaf area and the leaves must be in good health and vigor. The size of preceding crop and how well the nuts produced were filled. It seems that under conditions of heavy crop production, food material reserves left in the tree at the time of harvest are likely to be low. Free of insect and disease injuries.
Healthy foliage is needed to ensure photosynthesis is conducted to full capacity in the trees.
Insects affecting foliage or shuck will impair their ability to produce and conduct food materials, respectively. Weather conditions will likely have a big impact on nut development. Under conditions of prolonged drought, the kernels do not fill properly. Hot weather can also cause some sunscald or burning of the shucks and also affect filling of the kernel. This occurs mainly on the south and southwest sides of the tree when trees do not have a thick, dense foliage.