1. The nutrients made by leaves did not completely return to the tree. If pruning will cause waste of nutrients, the tree will be weak, which will have a great impact on flowering and fruit setting in the coming year.
2. Autumn is the peak of autumn infection period. If pruning is bound to cause a wound, germs can easily infect from the wound and aggravate the disease of branches.
For reference, thank you for your attention, please comment. Thank you.