Apple tree head cleaning refers to the cleaning and thinning of competing branches at all levels during pruning. This method can increase the ratio of branches to stems or coarseness. It is conducive to increasing the level of bone trunk branches at all levels, reducing the competitiveness of competitive branches against leading branches, easing tree vigor, and stabilizing tree vigor. Beneficial for cultivating fruiting branches with uniaxial extension.
During the summer pruning of apple trees, pruning the three or five pronged branches is called pruning. Generally, the competitive branches on the back should be cut flat and removed, while the two small leaves at the base should be retained when removing the competitive branches on both sides and below the back. It is beneficial for the robust growth of the leading branches, and the short pegs retained at the base can also sprout small branches, some of which can form flower buds in the same year.
The head cleaning work of summer pruning is mainly aimed at flourishing trees with strong tree vigor. The cleaning of the heads of moderate and weak trees should be carried out during the dormant pruning period, which is beneficial for rejuvenating the tree.
The time for head cleaning and pruning in summer should be controlled in two stages: early and late. Early, it is after the flowers wither in May and before bagging, when clearing the head is beneficial for the formation of flower buds. Late, it is in mid August when the top of the tree is cleared, which will not affect the physiological differentiation of flower buds and can reduce the amount of pruning during the dormant period and stabilize the tree vigor.
It should be noted that the long-term suspension of new branches in June and July is not suitable for clearing the head. At this time, clearing the head reduces the external tension and the stimulating effect of pruning. New shoots that have stopped growing in the inner chamber will sprout for secondary growth, which is not conducive to the formation of flower buds. Therefore, it is not recommended to clear the head in June or July.
