The wiring is only temporary and can only be on the tree for a relatively short period of time before you risk permanent scarring. After being held in position

The wiring is only temporary and can only be on the tree for a relatively short period of time before you risk permanent scarring. After being held in position for a long enough time, if done properly, will permanently shape the tree. Everything is controlled, there are even techniques for which buds to pick out so that the tree will direct resources to the proper parts for growth.