How to do winter pruning of apple trees? Detailed explanation of key pruning measures

In the training and pruning of apple trees, the choice of tree shape model must be targeted. For newly built orchards, the high spindle modern cultivation training method should be adopted. For old overcrowded orchards, a decision must also be made to carry out renovation.

The renovation of overcrowded apple orchards mainly adopts the principles of thinning out, raising the trunk, dropping the top, removing excessive large branches, and removing large lateral branches from large branches, so as to transform apple trees into a high-light-efficiency and labor-saving tree shape.

For apple trees of the three-main-branch delayed open-center shape and spindle shape under standard dense planting, the canopy must begin to be reshaped after 10 years of age. This also conforms to the growth and fruiting pattern of apple trees on standard rootstock. Changing an overcrowded and chaotic tree shape into a high-light-efficiency tree shape requires major surgery to solve the problem of too many scaffold branches. Many fruit growers are reluctant, and their first reaction is to feel distressed and unable to bring themselves to cut. In fact, this is because they do not understand the growth pattern of fruit trees. The management concept of high spindle apple orchards is more scientific.

To renovate an overcrowded orchard, first thin out the original temporary trees according to the situation, solving it in one go without leaving future trouble. Focus on renovating the retained permanent trees, mainly through reshaping and renovation, combining training with fruiting.

The reshaping of large trees is carried out in three steps:

Step one, raising the trunk: saw off the large main branches at the base year by year, and finally raise the trunk height to more than 1-1.5 m.

Step two, dropping the top: dropping the top must be carried out over several years, and finally the tree height should be controlled at 2.5-3 m to facilitate picking, spraying, and other field operations.

Step three, removing lateral branches: main branches should maintain single-axis extension. Focus on removing the large lateral branches on the selected retained main branches. Any lateral branch whose thickness exceeds 1/3 of the main branch should be gradually removed, and fruiting branches should be regrown, thoroughly solving the problem of competing branches.

During tree reshaping, attention should be paid to solving the problem of indistinct leader and subordinate branches, cutting out reverse-growing branches, and solving the problem of tree disorder. Some moderately vigorous branches should be properly retained on the upper side of main branches to prevent sunscald. Overlong drooping fruiting branch groups should be cut back for rejuvenation. After renovation, the fruiting positions should adopt a three-shift system, that is, there should be fruiting branches for the current year, fruiting branches for the next year, and fruiting branches for the third year. By retaining reserve branches, alternate fruiting is achieved, avoiding alternate bearing and ensuring high and stable yields with high quality year after year. During major reshaping, wound protection must be done promptly. Cut and saw wounds with a thickness of more than 3 cm need to be coated with fruit tree wound healing agent.

The finally formed tree shape maintains 4-6 large branches, and each large branch retains 20-30 small fruiting branch groups. The entire renovation takes 2-3 years to complete. Yield is affected in the first two years after renovation, and afterward the yield basically remains at the original level, but quality will be greatly improved.