Biological Characteristics of Tree Species and Varieties Fruit trees have different types and varieties, and their biological characteristics are also different. That is, for the same tree species, different varieties have different budding sooner or later, the number of branches, and the size of the branching angles. , there are obvious differences in the softness and hardness of branches, the composition and proportion of branches, the strength of the middle stem, the difficulty of forming flower buds, and the sensitivity to pruning reaction. Therefore, when pruning, it is necessary to adopt targeted pruning methods according to the different biological characteristics of tree species and varieties. Pruning according to tree species and varieties has become the most fundamental and important basis for plastic pruning of fruit trees.

There are obvious differences in the biological characteristics of different tree species, such as apples and pears: the top dominance of pear trees is stronger than that of apples. During the young age, the uprightness of the branches is stronger than that of apples, and they enter the fruiting period. Finally, the angle of the backbone branches is more open than that of the apple tree. The budding power of pears is higher than that of apples, but the branching power is weaker than that of apples. It is easier to form flowers and bear fruit earlier, but it is more likely to have large and small fruit than apples. The life span of hidden buds of pear trees is longer than that of apples, so pruning and renewal pruning is more convenient than that of apples. Due to the differences in the biological characteristics of apples and pears, when pruning, attention should be paid to the pruning of young pear trees. The degree of pruning of the main branches should be lighter than that of apples, that is to say, the pruning degree should be lighter than that of apples. Cut as much as possible; the height of the top of the main branch should be similar to the height of the central leading branch to prevent the phenomenon of strong top and weak bottom; in order to prevent the main branch from bending and drooping after the pear tree enters the fruiting period, the opening angle of the first layer of main branch can be It is relatively small and can generally be kept at about 40 degrees. It does not have to be adjusted to a base angle of about 80 degrees at the beginning like apple trees; pear trees have high germination power and are easy to bloom, so they need to be adjusted after entering the fruiting period. Pay attention to flower control; the stable bud life of pear trees is also longer than that of apple trees. Therefore, you can use the perennial hidden buds at the base to renew the backbone branches and crown. However, when the branches of apple trees that are more than 4 years old are pruned, it is more difficult to harvest. The ideal effect of renewal and rejuvenation may sometimes cause pruning to accelerate aging or dry out and die.

Among the different varieties of grapes, longan with high meristeous nodes on fruit branches should be trellised and long-tip pruned, while varieties such as Rose Xiang with weaker growth and lower meristeous nodes on fruit branches should be used , then fence shaping and short tip pruning should be adopted.

(2) Tree age and tree vigor Fruit trees have different age periods, and their growth and fruiting conditions are also different. Therefore, the methods adopted during shaping and pruning should also be different. Fruit trees such as apples and pears generally grow vigorously from their young age to the early fruiting stage, with fewer branches and leaves, more long branches, fewer medium and short branches, more upright branches, difficult angles to open, and fewer flowers and fruits. ; After entering the fruiting period, the growth of the tree gradually stabilizes, from vigorous to moderate to weak, the number of branches and leaves increases significantly, the number of long branches decreases, the proportion of medium and short branches increases, the angle gradually opens, and the number of flowers and fruits increases. . Therefore, during the pruning process, pruning methods of different severity should be adopted according to the growth and fruit characteristics of different ages: for young to early-fruiting trees, pruning should be done lightly to increase the total number of branches and the number of branches. Expand the crown of the tree to achieve early fruiting and early high yield; for large trees that have entered the fruiting period, pruning should be appropriately pruned, attention should be paid to regulating the number of flowers and fruits, and rejuvenation and pruning should be carried out to prevent tree aging and extend the fruiting life. For trees that are growing too vigorously, no matter what age they are, the amount of pruning should be light to facilitate flowering and fruiting; for trees that are growing too weak, measures must first be taken to strengthen the comprehensive management of soil, fertilizer, and water to enhance tree vigor and increase growth. After the number of branches has increased, appropriate pruning measures will be taken.

(3) Planting density and planting methods Tree species and varieties with different planting densities and planting methods will also have different pruning methods. Generally, in orchards with high planting density, attention should be paid to cultivating tree shapes with low branch levels, small skeletons, and small crowns when reshaping. When pruning, attention should be paid to opening the branch angles to control their vegetative growth, inhibit excessive tree crowns, and promote flower bud formation to maximize the potential of fruit trees. It has the potential for early fruiting and early high yield; for orchards with low planting density, the grade of branches and the total number of branches should be appropriately increased to quickly expand the crown of the tree to bloom and bear fruit; for fruit trees with planned dense planting and temporary density, permanent Different pruning methods should be adopted for permanent plants and temporary plants: for permanent plants, conventional pruning measures should be adopted, paying attention to both the tree shape and early fruiting. For temporary plants, when pruning, try to take pruning measures that promote flowering and fruiting, compress the crown, and control vegetative growth, so as to promote early and multiple fruiting without emphasizing the tree shape. When temporary plants affect the crown expansion of permanent plants, they must be retracted, pruned, transplanted, thinned or cut down according to the specific conditions.

(4) Pruning response Different tree species or varieties have different responses to pruning. Even for the same species, when the same pruning method is used to treat branches in different parts, the degree and scope of the reaction are also quite different. Therefore, the pruning reaction can not only test the severity of pruning, but also an important indicator of whether the pruning is reasonable. . Only by being familiar with and mastering the rules of pruning reaction can we perform pruning successfully.

The response to pruning depends first on the local performance, that is, the growth, flowering and fruiting conditions of the branches under the cut or saw cut, and secondly on the growth strength of the whole tree.