(1) pruning and shaping
In the young stage of fruit trees, the ventilation and light transmission of the crown is not the main contradiction because of its small volume and few branches and leaves. Therefore, the task of pruning is to cultivate the backbone branches first, so as to expand the crown as soon as possible and occupy all available space. Except for a few fruit trees, the crown of most arbor fruit trees can adopt the trunk shape of the central trunk, the main branches can be arranged in layers or without layers according to the structural requirements of the target tree, and the lateral branches can be cultivated on the main branches as needed. It usually takes 7 ~ 10 years to complete the young tree shaping.
(2) Pruning principle
The tree nature of young trees is robust growth and easy branching, which is the basis of pruning, flowering and fruiting of young trees. It used to be said that "small trees are prosperous, don't worry, small trees are weak and have a headache." However, this strong growth must meet the requirements of branch management, rather than let it naturally get out of control. Therefore, young tree pruning should follow the following two principles.
(1) The young branches are mainly promoted, and the combination of promotion and control is generally not afraid of too much, just afraid of less, not afraid of strength, just afraid of weakness. Therefore, pruning should be based on promotion. However, considering the unbalanced development caused by the local advantages of different branches, it is necessary to promote the combination of control and promotion. The specific pruning requirements of this principle are: for the full crown, promote the lower part, control the upper part and promote the internal control; For one branch, promote the latter to control the former, and promote the spring shoot to control the autumn shoot; For branches, promote short branches, control long branches, promote weak branches and control strong branches; According to different branches, promote the backbone branch and control the auxiliary branch; For the root system, promote small roots, control large roots, promote flat roots and control straight roots; According to different plants, promote permanent plants and control temporary plants. In short, when pruning young trees, the branches should be relatively divided to promote control and reasonable arrangement.
(2) Give priority to light and combine light and heavy. While shaping young trees, light cutting and slow release should be used to promote the development of short and medium branches, so that they can bloom quickly and bear fruit early. However, considering the cultivation of different types of branches, for some branches with large space, the method of continuous short cutting or cutting and inserting can be used to form a more compact branch group. The extension heads of backbone branches at all levels should be cut short at the full buds in the middle to ensure their growth advantages.
(3) the content and steps of pruning
Young tree pruning should focus on two central tasks: cultivating skeleton and promoting flowering and fruiting, and strive to be synchronized. In order to ensure the pruning quality and improve the pruning efficiency, the following steps can be followed.
(1) to cultivate the central trunk of the main branch and the extension heads of the main and side branches, the outer buds should be left in the middle, chopped according to the affiliation, and the bottom angle, waist angle and sharp angle should be adjusted as required.
(2) After selecting the backbone branch, the remaining branches can be retained as auxiliary branches, and the specific pruning methods should be treated differently according to the posture and growth of branches. Generally, the moderate branches that are flat, oblique and not vertical can be released slowly, while the upright and vigorous branches should be bent and weakened first, and then released slowly to urge them to throw short and medium branches to blossom and bear fruit. This experience of putting branches on hold for a long time to slow down their growth and then flowering and fruiting naturally is called "catching big fish in a long line" by fruit farmers.
(3) Continuous Pruning Through the combination of winter and summer pruning, the growth angles and directions of branches are constantly adjusted and fixed to ensure the growth advantages of backbone branches and control the excessive growth of non-backbone branches, so that the crown can develop according to the target tree structure and blossom and bear fruit as planned.