(1) The pruning method of cutting off part of annual branches is called short cutting. According to the degree of cutting, it can be divided into four types: light cutting, medium cutting, heavy cutting and extremely heavy cutting.
Light and short cutting: cut off the branches of 1/4 ~ 1/3, and leave the branches more than 50 cm. Its branches are characterized by a large number of branches, and the average number of branches is about 3. Light and short cutting weakened the top advantage of branches, eased the growth advantage of top branches, increased the number of short branches, and the upper branches were easily transformed into medium-long fruit branches and mixed branches. The growth roughness of lightly chopped branches is wider than that of moderately and severely chopped branches. Light and short pruning of horizontal branches and oblique branches of young trees is beneficial to early fruiting.
Medium and short cutting: cut off 1/2 branches, and the remaining branches are 45 ~ 50 cm long. The feature is that it is conducive to maintaining the top advantage. Generally, the branch strength ratio is light, the weight is short and the cutting is strong, and the new shoots grow healthily, with an average of about 4 branches and up to 5 branches. There are many branches after the short cut, and the branches are strong. Therefore, the short cutting time of young branches is too long and the short cutting amount is too much, which will inevitably affect the permeability of crown, leading to the phenomenon of long pruning period and late fruit. Medium-short cutting is mainly used for short cutting of main branches (such as extension branches of main branches and side branches), expanding tree crown, and also for cultivating medium-long fruit branches.
Heavy and short cut: the total length of cut branches is more than 1/2, and the remaining branches are about 35 cm long. Its characteristic is that it can strengthen the top advantage and promote the growth of new shoots. The number of branches is small, and the branching ability is weak, with an average of about 2 branches. It plays a role in balancing tree potential in the process of young tree shaping. In addition, you can also use the branches on the back to cultivate fruiting branches. When balancing the tree potential, the total growth can be reduced by cutting off the extended branches of the vigorous backbone branches. When the fruiting branches are cultivated on the back of the main branches, the weight of the branches should be shortened in the first year, and the middle and long branches extracted in the second year should be removed from the strong branches and kept weak, and the straight branches should be kept oblique.
Extremely heavy chopping: cut off more than 4/5 branches and leave 5 ~ 6 buds at the base. Extremely heavy stubble is rarely used on sweet cherry fruit trees, but only on annual branches for thinning. For branches that need to be thinned, if there are axillary flower buds at the base, extremely heavy short nodes can be used, and then thinning can be carried out after fruiting; There are no flower buds at the base, but they are extremely heavy and short, which can cultivate bouquetlike fruiting branches and control overgrown trees. In the process of spindle-shaped shaping in the young tree stage, in order to increase the ratio of stem to branch thickness and cultivate an ideal tree shape, extremely heavy and short cuttings are generally used, and 3 ~ 5 annual branches sprouting on the middle trunk are extremely heavy and short cuttings, so as to cultivate the bearing mother branches with fine branches and increase the number of bearing mother branches. In a word, short pruning can strengthen the growth of new shoots, increase the proportion of long branches and delay the formation of flower buds. (2) The pruning method of annual branches that are not cut short, let go slowly and let them grow naturally. The effect of slow release is just the opposite of short cut, mainly relaxing the branch potential and tree potential, adjusting the amount of branches and leaves, and increasing the number of fruiting branches and flower buds. Of course, the specific reaction of the branches after slow release often varies with the growth, position and growth direction of the branches. After slow release, especially after years of slow release, the upright branches with strong growth potential and superior planting position have a large amount of thickening and many bouquetlike fruit branches; However, the transverse branches and oblique branches with moderate growth have small growth, fast branch growth, high branch density, strong bouquet-shaped fruit branches and uniform distribution on the slow-release branches.
Therefore, it is one of the effective measures to increase the number of branches, slow down the growth, bear more fruits early and strive for early fruiting and high yield on young sweet cherry trees and early fruiting fruit trees. When the vertical competitive branches are released slowly, because the branches are thickened quickly, it is easy to disrupt the tree shape, so that the lower short branches die and the resulting parts are easy to move out. Therefore, the slow release of such branches should be coordinated with the opening of branches, reduce the number of long branches at the top, or combine with ring cutting. (3) Shrinking cuts or saws off a part of perennial branches, which is also called shrinking. Proper retraction can promote the germination of branches, restore the tree potential and adjust the proportion of all kinds of fruiting branches through the latent buds under the cutting mouth. Retraction is mainly used for strong trees or weak trees. In addition, retraction is mostly used for trees in the full fruit period of big purple varieties, while for varieties such as Naong, it is generally used as little as possible or not. Because after the branches are retracted, it is easy to cause the retracted branches to weaken. There are dead branches. When young trees shrink their branches, it is easy to cause the branches to be white and long, which leads to strong branching, too many branches and low fruit setting rate of shrinking flowers. Retracting and pruning the fruiting branches can make the remaining branches and buds have more water and nutrients, which is conducive to vigorous growth and flower promotion. Proper shrinkage and pruning can keep trees healthy, while aimless shrinkage easily affects yield and quality. (4) Cutting sparse annual branches or perennial branches from the base. Thinning is mainly used for large branches that are too busy, too dense or disturb the tree around the crown. Thinning branches is beneficial to improve light conditions in canopy, balance tree potential, reduce nutrient consumption and promote flower bud formation. During plastic surgery, in order to reduce the amount of pruning in winter, measures such as bud wiping, core removal and tip twisting should be strengthened in the growing season. For large branches that must be thinned, they are generally thinned after fruit picking. For most varieties of sweet cherry, pruning is rarely used, because the wound healing of cherry after pruning is slow, which is easy to cause gum flow in each growth period, leading to weak growth of young trees and premature death of fruit trees; Young trees have too many branches, slow formation, few branches, and low yield per plant in full fruit stage. Therefore, one drainage should not be too much, and it should be carried out in stages and batches.