When using metal wire for tying, you must first anneal the wire and burn it on the fire until blue flames appear. Take it out and cool it naturally, or place it in plant ashes to cool naturally. In this way, the wire becomes soft and the dazzling metallic luster is removed, making it easy to use. The pruning period must be appropriate, otherwise the branches should be broken. The best time for deciduous trees to be pruned is in autumn. It is better to carry out the entire dormant period from the time of leaf fall to early spring of the next year and before germination; while evergreen trees should be pruned during the growing period. The above-mentioned winding period is only a general situation, and the best period of winding for special tree species must be determined through practice. The thickness of the wire must be properly matched with the branches. Thin branches and thick wires are not only inconvenient to operate, but also easy to damage the bark. When the weather is hot in the future, the wire will absorb a lot of heat and burn the young bark. If the branches are thick and the wire is thin, the mechanical force cannot meet the requirements of the shape. For example, if the branch diameter is 1.4-1.5 cm, use No. 10 wire, 1.2-1.3 cm use No. 12 wire, 1.0-1.1 cm use No. 14 wire, etc. The length of the metal wire should generally be about 1.5 times the length of the branch being tied. Before tying, wrap a layer of hemp bark or nylon rope straps on the tree trunk to prevent the metal wire from strangulating the bark. The direction of winding the wire, if you want the tree trunk to twist and bend to the right, wind the wire clockwise, otherwise, wind it counterclockwise. When winding, it must be close to the bark of the tree. The wire direction should be at a 45-degree angle with the cross section of the branch. It should be spirally wound from bottom to top, from thick to thin to the top of the trunk. The spacing should be consistent and the tightness should be appropriate. If it is too tight, it will damage the tree. If the bark is too loose, the wire will move around on the branches and will not be effective. Before pinning, you must fully consider the direction of the branches and then start. Do not rework. While pruning, proper pruning should also be carried out. Excess branches that affect the shape must be cut off to ensure a reasonable distribution of branches. Clear layers. Pay attention to untying them in time after shaping, because the thinner branches grow thicker quickly. The iron wire can be removed after one year of pinning, otherwise the iron wire will be embedded too deep into the cortex, often causing leaves to fall and branches to wither. The thicker branches should be kept tied for two years before being removed. If the wires are removed too early, the branches will bounce back.