Pruning in spring is usually carried out before trees germinate. The main purpose is to promote the growth and development of trees, control the tree shape, improve the germination ability and promote the growth of short and medium branches. Pruning in summer is usually carried out after flowering, the main purpose of which is to improve the light, promote the growth of secondary branches, accelerate the formation of young trees, alleviate the tree potential and branch potential, and promote the differentiation of flower buds.
Autumn pruning is usually carried out after the autumn shoots stop growing or grow. The main purpose is to promote the growth of high-quality short branches, rejuvenate the inner branches, make the crown ventilated and transparent, promote fruit coloring and improve fruit quality. Winter pruning is usually carried out in the dormant period, the main purpose of which is plastic pruning, ventilation and light transmission, and rational allocation of fruiting branches and vegetative branches.