How to prune pear trees with an unreasonable structure

Currently, many pear orchards use high-density planting techniques for production. The single-layer high open-center form of pear trees is a tree form suitable for high-density pear orchards. Its suitable density is 44 trees planted per mu. The tree structure is a trunk height of 60-80 cm and a tree height of 3-3.5 m. The top of the central leader (not including the extension shoot) is 1.6-1.8 m above the ground. On the central leader, branch group basal axes or branch groups are evenly arranged, with a basal axis length of less than 30 cm. The vigorous long-bearing branch groups borne on the central leader or basal axes are required to reach 10-12 per tree. The whole tree has only one layer, and the final leaf canopy thickness is 2-2.5 m. However, some pear orchards are often pruned improperly, resulting in an unreasonable tree structure. The most common problems are an insufficient number of vigorous branch groups on pear trees and "bare legs" on the lower part of the branch groups. Different solutions should be adopted according to the specific problems.

Insufficient number of vigorous fruiting branch groups. The cause of this situation is that during winter pruning in previous years, the branches of branch groups that were shortened or renewal-pruned were too weak, and after shortening or renewal pruning, they failed to produce strong shoots and did not form vigorous fruiting branch groups; permanent branch groups were bent too early to open the angle, causing them to become weak branch groups; vigorous fruiting branch groups were not bent in time to open the angle, making the branch vigor too strong, causing an imbalance in tree vigor and resulting in newly cultivated branch groups being unable to grow well.

Solution: To cultivate vigorous fruiting branch groups, during winter pruning, shorten vigorous one-year-old branches or heavily renewal-prune vigorously growing perennial branches. For those one-year-old or perennial branches with weaker vigor, adopt the method of combining cultivation and renewal pruning to cultivate vigorous fruiting branch groups. For weaker branches, leave them unpruned for consecutive years to increase their number of branches and leaves, and reduce their fruiting amount to increase the growth vigor of the whole branch. For branches whose growth vigor has already recovered, during winter pruning, renewal-prune at the branch point with a plump terminal bud to promote the growth of vigorous new branches. For bending permanent branch groups to open the angle, wait until the branch group together with the terminal shoot reaches more than 2 m before doing it. For overly vigorous fruiting branch groups, depending on the specific situation, measures such as timely bending to open the angle, and during winter pruning removing some of the vigorous branches on them, or during winter pruning leaving 2-3 short branches for heavy renewal pruning and renewing the branch group, can be taken to balance tree vigor.

Permanent fruiting branch groups with "bare legs." The cause of this situation is mainly due to the upright growth of pear fruiting branch groups.

Solution: Bend the branch groups to open the angle, regulate growth vigor, increase crown width, and create good nutritional conditions and space for shoot sprouting on bare-legged branch groups. During winter pruning, renewal-prune the upper part of the branch group. On one hand, this can improve light conditions inside the crown; on the other hand, it can suppress the front and promote the back, prompting shoots to sprout from the "bare leg" part of the branch group. However, after renewal pruning, the length of the main axis of the branch group must be more than 2 m.