The aboveground branches and underground roots of fruit trees are a closely related and mutually restrictive unity of opposites. After planting fruit trees, after a certain period of growth, the crown and root system as a whole established a relatively stable equilibrium system on the basis of mutual supply and demand. In the process of tree growth and development, if either party is injured carelessly, this balance will be broken, thus weakening the growth and development of the other party. This principle is of great significance in old tree renewal and big tree transplantation. Therefore, the balance between branches and roots should be considered when pruning fruit trees, and the retraction of perennial roots should not be too hasty, so it should be reformed step by step. Otherwise, due to the natural balance of the trees themselves, it is easy to cause peeling and affect the normal results.

For example, in the orchard of Zhaoyuan Village, Xiangning County, Shanxi Province, the three-year-old short-branch apple tree was straightened again and then transformed into shrinkage because the technical director later disagreed with the way of oblique planting and shaping. As a result, the short branches with flowering ability on the trunk and the central trunk have all grown up because of too much stimulation. The most serious trees have as many as 27 branches over 80 cm long.

In this way, the original slow-growing young apple trees with the ability to blossom and bear fruit were pruned back to "childhood" and lost their ability to blossom and bear fruit. The reason why this happens is that when pruning perennial branches, the trimmer did not take into account the balance relationship between branches and roots established by trees after three years of development. Based on this lesson and experience, some pruners pruned and reformed the crown and root system of the underground part while retracting and renewing the old trees, and achieved good regeneration and rejuvenation results.