Sometimes there are structural problems that can’t be addressed by pruning alone, because the required pruning dose would be so severe that it would undermine the tree’s other leaders. Often we can address these hazards by using hardware to add support.
Take for example a large tree with co dominant leaders:
The annual growth of both halves of this tree adds weight which tends to pull the two leaders in opposite directions. Furthermore, the union between the two trunks is weak, having bark tissue included in the branch union which is preventing the live wood inside from forming a strong connection.
To remove one half of the tree would inflict a large wound at the base of the remaining leader which can never heal. Instead we install braces through the weak branch union and a rather stretchy cable up in the top which prevents the two leaders from separating enough to split apart.
Thus the whole canopy is preserved and the hazard greatly reduced with the use of simple materials. This system can be scaled up to support any number of stems of various sizes and weights using different gauge cable as needed.