Cabling or bracing a tree helps to support the life of a tree. Trees that have more than one trunk (trees that form a “V” shape, see pictures below for examples) are prone to crack or split. By installing a cable it reinforces the weak spot in the tree to prevent it from cracking or splitting
Cables:
Cables are installed to limit the limb movement at weak points in the tree to prevent it from cracking due to wind or accumulated snow.
Braces:
Braces are steel rods installed to form a firm support in limbs and other parts of the tree. They are used to repair and reinforce split, weak or decaying areas of the tree.