Wire Under Tree Bark

Question

I just noticed a wire (probably used to hold a hammock}

Answer 1

This is quite common, and usually not much harm to the tree. In fact, it would do more damage to attempt to remove it! If it becomes an eye-sore, it will not hurt to trim it off level with the tree bark. Normally, fence wires, or similar, such as something to hold a hammock, will go unnoticed by the tree.