After deciduous shrubs are dried, we should pay attention to the number and distance angle of main branch buds. Generally, the number is 3 or 5, and the angles are the same. Leave three main branches, one facing due north, the other two, one facing southeast and one facing southwest; Leave 5 branches at about the same distance. There are two ways to treat the remaining buds, one is to erase them completely, and the other is to remove the growing points and leave more leaves, which will help the trunk to thicken. The height of the fixed stem is generally 50-80cm. Leave more leaves on the buds of high grafting trees, which will help to thicken the trunk. Generally speaking, the fixed stem height is completely erased to prevent the scion from competing for nutrients or affecting its survival. Cutting off a part of an annual branch is called chopping. There are four kinds of shortcuts: light shortcuts, medium shortcuts, heavy shortcuts and extremely heavy shortcuts.
(1) light and short cutting: only the top of the branch is cut off, which generally does not exceed one fifth of the total length of the branch. Mainly used for pruning the thick branches of flowers and fruit trees. The purpose is to stimulate the germination of lower buds, disperse the nutrients of branches and promote the growth of short branches after cutting off the top tips. These short branches generally grow moderately, stop growing early, accumulate sufficient nutrients, and easily form flower buds.
(2) Medium-short cut: cut at the full bud of the middle and upper branches. Generally less than half of the total length of the branch. Because the cutting buds are full and the branches are nutritious, there are many nutritious branches that grow vigorously. Used for rejuvenation of weak trees and cultivation of extended branches of main branches.
(3) Heavy and short cutting: more than half to four-fifths of branches are cut off. Almost 80% of the branches have been cut off. More exciting. In general, vigorous vegetative branches germinate. Mainly used for regeneration, rejuvenation and pruning of weak trees and branches.
(4) Extremely heavy cutting: that is, only 2-3 buds are left at the base of the branch for cutting. Because the cut bud is at the base, the quality is poor. Generally, they are short-germinated vegetative branches, and some can germinate vigorously. Mainly used for renewal and rejuvenation.
It is possible that all cutting methods can be used on one plant, such as drupe and drupe shrub, peach, elm plum, purple plum, purple peach, cherry, apple and pear. The branches of the main branch are cut short, the side branches are cut short, and the open inner chamber is cut short or extremely short. Like hanging seedlings, such as Sophora japonica, peach, elm, apricot, etc., the branches are drooping, and generally only one method is used, that is, heavy and short pruning, and 90% of the branches are cut off. Promote the germination and growth of upward and forward growing branches to form a round crown. If you use light cutting and short cutting, the branches will become weaker and weaker and unable to form a crown.
4. Thinning: Cutting off all branches or branches from the base is called thinning. Sparse branches can be annual branches or perennial branches. The function of thinning branches is to enhance the growth potential of the remaining branches, because their nutrient area is relatively expanded, which is beneficial to their growth and development. However, the growth potential of the whole tree is weakened and the growth amount is reduced. After thinning, there are fewer branches, which improves the ventilation and light transmission conditions of the crown. The branches are evenly distributed and placed reasonably, which is beneficial to the formation of flower buds and the flowering and fruiting of flower and fruit trees. Such as pruning apples, pears and peaches. Too dense and crowded branches, poor permeability, are generally solutions. The principle of keeping branches is that sparse is better than dense. For another example, in order to cultivate a straight trunk, annual or biennial seedlings are often cut off, leaving only one bud or a branch at the base as the trunk. This method actually belongs to thinning pruning, just sparse. Conifer species have too many verticillate branches, which are too dense and crowded, and some often remove the verticillate branches or branchlets from the trunk to make the crown clear and improve the ornamental value.
5. Branching: Branching is to change the original direction and position of branches or big branches to continue to grow, such as conifers such as spruce and Pinus tabulaeformis. For some reason, the branch in a certain direction is damaged or missing. In order to make up for the missing branch, the method of pulling branches to both sides of the missing branch can be used to make up for the original crown defect. Otherwise, it will become a waste seedling. The most commonly used branch pulling is to cultivate large seedlings of flowers and fruit trees. Because the angle of the main branch is too small, the purpose of opening the angle cannot be achieved by pruning, so it is only appropriate to do it hard. In the method of opening and pulling branches, the main branch angle is generally about 70 degrees. Opening branches is better than other pruning methods. Branching changed the space occupied by the tree crown, and some even increased the space by 50%. The nutrition area is expanded and the ventilation and light transmission conditions are better. Pulling branches can also turn a strong tree into a medium tree, so that the tree will soon relax and be conducive to flowering and fruiting.
6. Carving: A method of removing part of bark or xylem from a branch or trunk with a knife or scissors, thus affecting the growth of the branch or trunk, which is called carving. Incision cuts off a part of the conducting tissue of phloem or xylem, which hinders the downward transportation of nutrients and the upward flow of juice. After the branches or branches of plants are cut off, in order to heal, nutrients accumulate in the cut-off parts, and at the same time, due to the blockage of the wound. Nutrients are mainly transported upward from the roots, which absorb water, mineral nutrients and a small amount of organic matter, and can store nutrients and synthesize organic matter, especially cytokinin, gibberellin and auxin. Moreover, nutrition always comes from or accumulates under the cut, affecting the buds or branches above and below the wound. When cutting at the top of a bud or branch, nutrients accumulate under the incision, which can stimulate the growth of the bud or branch under the incision. When the wound is cut under the bud or branch, nutrients still accumulate under the wound, which inhibits the growth of the branch or bud above the wound. The application of carving injury in seedling raising is mainly in the lack of branches. In order to promote the emergence of branches, we can carve on the top of the bud to accumulate nutrients on the bud, promote the growth of new branches and make up for the missing branches. You can also suppress branches or groups of branches by carving.