1. Leave 3-4 basic branches as main branches and extend obliquely in different directions. The main branch bears lateral branches, which bear vegetative branches and fruiting mother branches. The whole tree forms a natural happiness tree with a height of 3 ~ 5m. Trunk pruning procedure: the first year: planting 1 year-old seedlings, the seedlings themselves often do not have three basic branches, so the trunk should be pruned again, leaving about 20cm of stem to promote the germination of basic branches, and the main branches should be selected in the second year.

2. In the second year: select 3-4 basal branches in different directions as main branches, lightly cut short, leave 2/3 branches, leave full buds and lateral buds at the cut, and cut the rest basal branches from the base.

3. In the third year: lightly cut the selected main branches and lengthen the branches. Choose 2-3 lateral branches for each main branch and lightly cut the short branches. Form a heart-shaped crown, and the branches from the ground to 40cm high on the main branches are cut off from the base. Pay attention to remove sprouted branches in time.

4. In the fourth year: continue to cut short the extended branches of the main side branches at all levels, and pay attention to cutting branches and sprouting branches below 40cm. Make the crown continue to expand, and the crown has basically formed.