I am aware of wire being used on pines for two reasons (there may be more). First, some black pine, particular cork bark pines have friable, fragile bark which can flake/break off. This thick bark is desired, and the wire used to help keep it on. Second, early in development, wire has been used on pines, particularly white pine, to score the bark (left on for a couple of years until it bites in), which results in rougher texture when tree heals (the end result is controversial in my mind), yet done and published in Japanese literature.