What should I do if the trunk of Ziwei transplant is broken?

Generally no problem. As long as more than half of the bark is not removed, there is no problem. Because the water of trees is transported upward from the roots through xylem ducts, and the products of leaf photosynthesis are transported downward to the whole body through the sieve tube of bark, some injuries will not die. If the bark enclosure is cut off more than 1 cm, it will be difficult to heal and lead to death. As the saying goes, "people want face, trees want skin" is the truth.