The young tree period is from seedling planting to early fruiting. This period is characterized by vigorous growth, strong uprightness, small trees and few branches and leaves. The main task of pruning is to make use of the advantages of vigorous growth, give priority to cutting, choose to cultivate backbone branches and arrangement of trees skeletons, quickly expand the crown, ease the tree vigor, and create conditions for early flowering, early fruiting and early high yield.

① Cultivate the backbone branches, quickly expand the crown and fix the stem, and then combine with bud grafting to promote germination as soon as possible and increase the amount of branches and leaves. According to the requirements of plastic surgery, select and keep the backbone branches for as long as possible, and choose the ones with strong buds. Strictly control the competitive branches, and generally should be relieved. If branches are used, they should be split and girdled, which will weaken growth and promote early fruit. When the crown diameter basically reaches the required size, the extended branches of the trunk should be released slowly and cannot be cut short, so as to slow down the growth and increase the germination number of short and medium branches. To prevent the distinction between the main branch and the secondary branch, the secondary branch should make way for the main branch and make it bear fruit early by pruning in summer.

(2) Cut gently and slowly, and make full use of auxiliary branches. In addition to short cutting and popularization of 1 ~ 2-year-old young trees due to insufficient branches, light cutting, less thinning and more branches should be maintained. This is the first condition to increase the number of branches, relieve tree vigor, promote flowering and fruiting, and realize early high yield. In order to enlarge the crown, except for the extension branches of main branches and side branches, the auxiliary branches are generally thrown away after being dense, and the main branches make way by pulling branches. After the results are obtained, the methods of refinement, release and contraction are adopted in time according to the actual situation. With the expansion of the crown, attention should be paid to the cultivation of fruiting branches to ensure good ventilation and light transmission in the crown.

(3) The key to improve the tree structure is to pull branches and open corners to alleviate the growth of the tree and ensure ventilation and light transmission. The opening angle of the main branch can ensure the advantage of the central branch and slow down the growth of trees, which is not only conducive to ventilation and light transmission, but also conducive to flowering and fruiting. The main way to open the corner is to pull the branches. The suitable time for pulling branches is spring and autumn (September), and the requirements for pulling branches are: "Don't go into the ground, don't drill into the sky, don't bend over, don't turn around, and form a line before and after", so as to play the role of pulling branches.

(4) Cultivate branches to prepare for high yield. Branches are the basic unit of fruit. The fruit branches of the first fruit-bearing tree are mainly planted on the auxiliary branches in the early stage. In the later stage, with the expansion of crown and the increase of tree age, fruit branches gradually transferred to backbone branches at all levels.

(2) Pruning of trees in full fruit period

Apple trees enter the full fruit stage after 8 ~ 10 years. At this time, the vegetative growth has gradually eased and the tree skeleton has been formed. With the increase of tree age, the yield increased year by year and tended to be stable. In the later stage, the tree vigor gradually weakened with the increase of fruit, and there were often phenomena such as tree vigor weakening, crown closure, fruit moving out, fruit bearing in different years and so on. Therefore, the main task of pruning is to adjust the relationship between growth and fruit, and improve the illumination in the inner room.

① Solving the illumination, ensuring good ventilation and light transmission in the crown, and placing the maximum number of leaves under the optimal illumination conditions are the basic tasks of fruit tree pruning in this period. To solve the lighting problem, we should first widen the angle of the main branches (including large auxiliary branches), gradually remove the redundant large branches in the crown and open the layer; Secondly, it is necessary to remove the auxiliary branches or branches that are too dense, so that the branches will not be handed over and the branches will see the light. During this period, the extended branches of fruit trees were not cut short, and the peripheral branches were sparse. Appropriately reduce the number of peripheral branches to become a "three sparse and three dense" crown with sparse upper branches and dense lower branches and sparse outer branches and dense inner branches.

② In the rejuvenation branch group, the auxiliary branches that are too dense are properly thinned and the branches that are too thin are filled. Branches should be updated in time. When updating and pruning, we should pay attention to keeping young fruit branches that are 2 ~ 3 years old, and updating old fruit branches that are more than 5 years old, so that the fruiting branches on the branches are generally kept within the age range of 2 ~ 4 years old. Branches should be fixed in place, the growth direction should be clear, and there should be shrinkage when pruning. In the branch group layout, it is required that the inside is large and the outside is small, and the bottom is large and the top is small, each occupying a certain space, which is in line with the main branch direction.

(3) Reasonably adjust the proportion of branches. Trees in the full fruit period should look at the pruning of flowers to ensure strong branches and balanced results. Through pruning and adjustment, the branches and the branches in the branches bear fruit. A certain number of flower buds, a certain number of flower preparation branches and a certain number of development branches are required in the same branch group. In the case of insufficient flower buds, leave the flower buds as soon as possible and try to keep the fruit branches; When there are enough flower buds, firstly, the weak branch flower buds are loosened, and the strong fruit branches are selected to bear fruit; When there are too many flower buds, the flower buds at the top of medium-long fruit branches should be broken, leaving only short fruit branches to bear fruit. Through the adjustment of pruning in winter and pruning before flowering in spring, it is appropriate to keep fruit branches (buds) accounting for about 20% ~ 30% of the total number of branches after pruning.

(3) Pruning of aged trees

The pruning of aged trees should focus on rejuvenation on the basis of strengthening the prevention and control of soil, fertilizer, water and insects. Big branches are light and sparse, resulting in fewer wounds; Branchlets should be fully rejuvenated and enhance their vitality.

(1) Select the prepared branches to cultivate new heads. Pruning old trees will basically keep the original skeleton unchanged. In the 5-6-year-old part of the main branch, the original lateral branch or newly sprouted branch is selected as the preparatory branch to replace the original head for cultivation.

(2) Making full use of the branches on the back leads to the senescence of the tree, and the mortality rate of single-axis fruit branches and drooping branches in the crown is very high, and the resulting parts are transferred to the branches on the back, sides and periphery of the crown. In order to concentrate nutrition, we should gradually remove the drooping branches and delicate fruit branches in the crown, fully cultivate and utilize the fruits of the back branches, renew and rejuvenate the bearing branches on both sides, leave more buds on the branches at the incision, improve the angle of branches and improve the bearing capacity.

(3) Rational utilization of the clustered branches on the crown. Generally, the overgrown branches are not removed, and they are shortened according to the size of space and the fullness of buds, so as to increase the amount of branches and leaves and cultivate the main branches or fruiting branches.

4 Sparse too many buds. When there are too many flower buds, they should be properly thinned to prevent them from bearing fruit in different years.