Shaping and pruning technology
1. Seedbed pruning: Seedlings generally do not need pruning.
2. Cultivate the big seedlings of plastic surgery
(1) For plants that have not been pruned in the nursery, in order to reduce the weakness of Pinaceae plants that are easy to flow gum and affect their growth, they should be pruned in winter when the sap flow is the lowest, and 2 ~ 3 main branches that develop evenly around should be kept, and the included angle between the main branches and the lateral branches should be kept close, and the main branches that are too dense should be cut off. For branches that are too thick, the branches that grow vigorously should be truncated or cut off to keep the stems and branches clear, and the thickness should be based on the thickness of the trunk.
② If trees with straight trunks are to be used as shade trees, they must be pruned, and the pruning period should be carried out in winter.
③ Leaf picking or thinning: The leaves at the base of branches of Pinus thunbergii should naturally turn yellow and change leaves every year from 1 1, and can be picked manually if necessary. If the needles of the whole plant are dense and airtight, some needles can also be removed to increase ventilation.
(4) Core-picking: The core-picking pruning of Pinus thunbergii is carried out in March-April every year when the new buds are elongated but the needles have not been drawn out. Generally, the length of each terminal bud is 1/3- 1/2, and coring can increase the crown density.
⑤ Sparse buds: Because the buds of Pinus thunbergii are rotated, multiple branchlets will grow at the top of the same branch, which can be combined with sparse buds when coring, that is, 3-4 buds in different directions are reserved when coring, and the rest are peeled off by hand. Sparse buds can promote the growth of main shoots.
3. Pruning after transplanting out of the nursery: when transplanting out of the nursery, dig with mud balls, prune the branches that are too dense, and properly pick leaves to reduce evaporation.