(2) Pear trees like light more than apples and are more sensitive to light intensity. Generally, when the light intensity is above 60%, it is easy to form full flower buds, and when the light intensity is below 30%, it is difficult to form flowers. When the canopy is closed and the light is insufficient, the fruiting branches in the inner chamber, especially the branchlets, are prone to aging or death. It is not advisable to leave too many or too few branches when pruning. Considering the planting density and the angle of main branches, the number of main branches can be appropriately increased and the distance between layers can be appropriately reduced in the young tree period; With the growth of tree age, the interlayer distance of main branches should be appropriately increased, and attention should be paid to adjusting branches and branches of various parts of the tree.
(3) When pruning, there are differences in the number of main branches, the length of short nodes, the cultivation of branches, the degree and method of pruning: for varieties with strong branch forming ability and germination ability, branches should be thinned appropriately, with fewer short nodes and fewer retractions to avoid too many new branches; Varieties with strong germination and weak branches can be released slowly, cut lightly and cut short, with few branches, and the number of main branches of the whole tree can be properly reserved.
(4) Compared with apple trees, the growth potential of single branch of pear trees is quite different, and the strong branches of medium and short branches are weak. Because of the heterogeneity of buds, the top of the new shoot of the same branch is long and thick, and the lower part is obviously weak, so the growth potential of a single branch is quite different. In most pear varieties, long branches are easy to grow and short branches are easy to grow, such as Apple pear and Jinfeng pear, but it is difficult to grow medium and long branches on short branches. Therefore, most varieties are mainly short fruit branches after fruiting, and short fruit branches have a long life. When pruning, we should pay attention to thinning the old branches and buds to make them renew and rejuvenate. When thinning, leave the edge in the middle, bottom, top, weak edge, dense edge and near edge. Special attention should be paid to the cultivation, regeneration and rejuvenation of different types of branches and fruiting branches.
(5) The branches of pear trees are more brittle and hard than apples, so it is not suitable to open flowers during dormancy. Young branches of pear trees stand upright, with small and hard branch angles, which are not easy to open. After the full fruit period, the backbone branches are more open and the branches are easy to droop. The crown of most young pear varieties is conical, which affects the early flowering and fruiting. It is necessary to open the main branch angle as soon as possible when trimming, but too much opening will weaken the growth potential of the extended branches. The main branch angle of young pear trees is generally smaller than that of young apple trees. With the growth of tree age and yield, the main branch competition year increases. When the crown of pear tree gradually reaches the late stage of full fruit, the angle of main branch increases, and its top is easy to sag, so the angle should be raised in time. Pear tree branches are brittle and hard, and the base is easy to crack under heavy pressure, especially during dormancy, so special attention should be paid to shaping and pruning in winter and spring. The angle between the main branch and the lateral branch of pear tree should be carried out in June-July during the growing period. The younger the pear branches are, the more brittle they are, and the 1-2-year-old branches are the most brittle, so it is not suitable to twist the pear treetops in summer. In summer, pruning should take measures such as bare branches, bent branches and falling branches, and in the future, the perennial branches with sparse branches will be girdled.
(6) Pear branches stop growing earlier than apples, and the terminal buds are full and easy to form. Short branches generally have no lateral buds except for a few varieties, and individual young pear trees, flourishing trees and flourishing branches grow more than twice. Because the branches stop growing early, most of the long and middle branches are covered with terminal buds, which have strong branch-pulling ability and are easy to form terminal buds and axillary buds. Pear trees have short branches and short internodes, and there are often no lateral buds between leaves and leaf axils, or only lateral buds. The buds are underdeveloped, but the terminal buds are full. Therefore, the short branches of pear trees should not be cut short, and it is often difficult to germinate after cutting short, which leads to the death of branches.
(7) The life span of hidden buds of pear trees is longer than that of apples, which facilitates the regeneration of backbone branches, such as rejuvenation of old pear trees. There are secondary buds at the base of pear branches, which are well developed and generally not suitable for germination, and become latent buds (hidden buds), with a long life. However, when stimulated by mechanical injury or pruning, it is easy to germinate or branch, which is convenient for the renewal and rejuvenation of old trees and backbone branches, and has strong regeneration ability after renewal.
Pear trees bloom more easily than apple trees. After the long branches of pear trees are slowly released, flower buds usually form in the same year. After the short branches bear fruit many times, they can continue to grow on the fruit table, which is easy to form short fruit branches. Short fruit branches have a long life, but their growth is easy to weaken after multiple fruits or continuous fruits, such as apple pears and early crisp pears, which should be thinned, refreshed and rejuvenated in time. In order to promote early fruiting and high yield of young pear trees, on the basis of supporting branches, bending branches and opening angles, annular peeling combined with summer pruning should be adopted to promote the formation of flower buds, which is more obvious than that of apples.
(9) Pear trees are prone to senescence after fruiting, and the crown of pear trees is erect, strong at the top and weak at the bottom, which leads to the outward movement of fruiting parts faster than that of apples, which affects high and stable yield. Therefore, it is necessary to make full use of the thick and long branches in the inner chamber to slow down the flower buds, update and trim the branches in the inner chamber, control the polar growth and solve the lighting problem, so as to obtain better harvest. Only by correctly distinguishing the difference between apples and pears and rationally applying pruning techniques can we achieve the goal of high and stable yield.