Detailed Explanation of Branch Growth Characteristics in Fruit Tree Bonsai

  Branches are an important component of the tree canopy and tree form. They not only bear leaves, flowers, and fruit, and transport water and nutrients, but are also important organs for nutrient storage. Thick trunks and strong branches are an important guarantee of consecutive years of fruiting in potted trees.

  Under suitable conditions, the branches of some fruit trees can produce adventitious roots; for example, grapes, citrus, lemons, pomegranates, figs, and others are commonly propagated by the cutting method.

  Branches can be divided into vegetative branches (growth branches) and fruiting branches. Those bearing only leaf buds are vegetative branches. Such branches generally grow vigorously, with plump buds, and can form the framework of the tree. Those bearing flower buds, or a regular mixture of flower buds and leaf buds, are fruiting branches. The number of fruiting branches determines the yield of the potted tree. Therefore, trees that have not yet fruited should be cultivated as quickly as possible to produce enough fruiting branches, while trees that have already fruited should, while growing the fruit well, also cultivate strong, healthy fruiting branches to ensure flowering and fruiting the following year.

  The order of branching has a direct effect on growth and fruiting. Young apple trees with a low order of branching grow vigorously and are difficult to bring into flower. Through pruning and grafting measures, increasing the order of branching and moderating growth vigor is an important way to achieve early flowering and early fruiting.

  The ability of buds to sprout into branches is called sprouting ability. The ability to produce long branches after sprouting is called branching ability. When both sprouting ability and branching ability are strong, a well-rounded tree form can be formed in the same year after potting, while hawthorn is weak in both. Within the same tree species, young trees have strong branching ability, while old trees have weak branching ability. Based on this characteristic, when pruning, trees with strong sprouting ability and branching ability should have more branches thinned out to reduce the number of branches; conversely, more heading back should be done to promote branch production, thereby regulating tree form and branch quantity.

  The apical dominance of branches is shown by the fact that the terminal bud or stem tip often inhibits the sprouting and growth of the lateral buds below it. The branch formed by the sprouting of the terminal bud has the strongest growth vigor, weakening progressively downward to the point where sprouting may not occur. Removing the terminal bud or tip can promote the sprouting of lateral buds and the growth of lateral branches, but the first lateral bud located at the tip still maintains apical dominance.

  The vertical dominance of branches is shown by the fact that upright branches grow vigorously, while slanted branches have weaker growth vigor and increased branching; horizontal or drooping branches have less growth, and their branches become noticeably shorter and weaker. In addition, after branch bending, the upward-growing water sprouts or upward-facing buds at the bent part of the branch are very likely to sprout into rampant growth.

  By making use of apical dominance and vertical dominance, the tree canopy can be rapidly expanded and shaping and styling can be carried out purposefully. However, the strong branches formed in this way often make the tree form of a small potted tree disordered, and this must be strictly controlled, especially for trained trees and trees that have already fruited. Methods such as changing the direction and angle of branches, timely pinching, or even complete thinning out can be used to prevent "trees growing on trees" and excessive tree vigor, as well as situations such as producing only branches and leaves without flowers or fruit.

  The relationship between branch growth and fruiting is shown by the fact that trees that have not yet fruited grow vigorously; once they fruit, the growth vigor of the branches weakens, and the size of the tree canopy is easy to control; excessive fruiting causes weak branch growth, an increased proportion of short branches, and a reduction in flower-bearing branches.

  The relationship between branch growth and rootstock is also very close. For the same variety of the same tree species, when grafted onto a vigorous rootstock, the growth vigor of new shoots, the duration of growth, the number of branches produced, the ratio of long to short branches, and the occurrence of flower buds all show noticeable differences. Therefore, although the variety is the same, if the rootstock is different, the technical management measures should also differ accordingly.

  In addition, branch growth is greatly affected by the pot used. A large pot not only provides more nutrients but also allows for a larger root system, which results in strong, vigorous branches. Since root growth and aboveground growth maintain a certain balance, reducing root system volume also effectively controls excessive growth. The smaller the pot used, the shorter the branch growth, the slower the thickening of branches and trunks, and the easier the size of the tree canopy is to control.