1. First, the results are early and the economic life is prolonged. The difference in fruit yield between the early and early stages of fruit trees is due to the different biological characteristics of tree species and varieties, the comprehensive management of soil, fertilizer and water, and the comprehensive prevention and control level of pests and diseases: peaches, apricots and pears are eaten for five years, while apples are eaten for seven or eight years. It can be seen that there are great differences between different tree species entering the fruiting period. That is, there are great differences among different varieties of the same tree species, such as Jin Shuai, Celosia cristata, Huang Kui, Fuji and Yanqing. Apples blossom and bear fruit earlier, usually 2 ~ 3 years after grafted seedlings are planted. However, it takes 5-7 years for Starkrimson, Guoguang and India to blossom and bear fruit after planting, and the fruiting period of the same apple variety grafted on dwarf rootstock can be advanced by 1-2 years. If corresponding pruning technical measures are taken according to the difficulty of flowering of tree species and varieties, the fruiting period can be advanced. For trees and varieties that are not easy to blossom and bear fruit, measures such as increasing the angle of backbone branches, keeping more branches, slow cutting and pruning in summer can also promote early flowering and bearing fruit; In hybrid breeding, pruning measures such as twisting branches, bending branches, pulling branches and opening angles can effectively adjust the growth and extension direction of branches, which is conducive to improving the light conditions of trees, the accumulation and distribution of nutrients, shortening childhood, thus regulating the growth and development of fruit trees and promoting flowering and fruiting.

2. The second is to improve the lighting conditions of trees. The length and intensity of light have great influence on fruit yield. Among deciduous fruit trees, peaches and apples like light the most, followed by grapes, pears and chestnuts, and persimmon trees are more tolerant to shade. The results show that the condition of flower bud formation is that the short branches must have more than 50% available light, so that half of the short branches can form flower buds. However, most fruit trees without pruning have closed crowns, and the internal illumination is lower than 30% of the natural illumination, that is, lower than the light compensation point. Therefore, the nutrition made by these leaves is only for their own consumption, and sometimes it is not enough, so it is difficult to bear fruit. Plastic pruning can improve the efficiency of photosynthesis of fruit trees, such as choosing suitable tree shape, widening the angle of backbone branches, reducing the number of backbone branches, reducing the height of trees and the thickness of leaf curtains. It can improve the lighting conditions and increase the effective leaf area; By reasonably increasing fertilization, improving leaf quality and photosynthetic efficiency and prolonging photosynthetic time, the accumulation of photosynthetic products can be increased, which is beneficial to flowering and fruiting. For example, for young trees and flourishing trees, light pruning, long planting, multi-branching, changing the extension direction of branches and adjusting the density of branches can effectively improve the light conditions of trees, enhance the photosynthetic efficiency of leaves, reduce ineffective consumption, increase the nutrient accumulation of trees, and be conducive to flowering and fruiting and increase early yield; However, if several young people cut and put them for a long time, there will inevitably be bad phenomena such as branch cross, leaf curtain thickness and poor lighting conditions, which will affect fruit yield, quality and economic benefits. On the other hand, if replanting is done year after year, the light conditions of trees can be improved. However, due to the overall weakness, the nutrient growth is too fast, the branches are too long, the nutrient accumulation in trees is insufficient, and it is difficult to blossom and bear fruit, and the yield is often low.

3. The third is to improve the nutrition of trees. Plastic pruning can improve the metabolic capacity of trees and improve their nutrition. The storage nutrients in fruit trees are basically carbohydrates and nitrogen-containing substances, and their content and proportion have great influence on the growth and fruit of trees. The research results of Fruit Research Institute of China Academy of Agricultural Sciences showed that five-year-old Redjade apple trees were pruned in early April. Two weeks later, it was found that the contents of nitrogen and water in pruned tissues were much higher than those in untrimmed tissues, while the contents of starch and sugar in pruned branches were lower than those in the control. This shows that pruning changes the nutritional composition of fruit tree branches, which is beneficial to the formation of flower buds and early yield improvement.