Pruning: the specific operations of cutting and thinning out the branches, buds, leaves, flowers, fruits, roots and other organs or tissues of trees.    

1. Purpose and significance of pruning  Ensure the health of trees; cultivate tree shape and control tree size; ensure the safety of life and property; regulate the relationship between trees and the environment; Adjust the balance of the various parts of the tree; promote the water balance of the tree to ensure the survival of transplanting; adjust the balance between the organs ("promotion and control" dual role); promote the rejuvenation and renewal of old trees.    

Second, the regulation mechanism of pruning  Adjust leaf area, change light conditions, so as to adjust the level of nutrient synthesis and nutritional status of the tree; adjust the ground/underground balance, affect root growth, Thereby regulating the absorption of inorganic nutrients and the distribution of organic nutrients; regulating the number, proportion and type of vegetative organs/reproductive organs, thereby regulating the nutrient accumulation and metabolism of the tree; controlling the ineffective branches and leaves and adjusting the number of flowers and fruits to reduce the ineffective consumption of nutrients; adjusting the angle of branches , The number of organs, conduction pathways, growth centers, etc., to transport and distribute nutrients in a targeted manner.   Summary: Pruning uses and changes the apical and vertical advantages by adjusting the position, number and type of organs, the pruning effect of different periods and the relative independence of the local area, and the heterogeneity of the development of the tree and the difference in tissues and organs. Regenerative, regulate tree nutrition, achieve the purpose of regulating growth, flowering and fruiting, and rejuvenation.   Pruning has a dual regulating effect of "promoting and controlling".   Pruning must be coordinated with soil, fertilizer, and water management to give full play to its regulating effect.