Magic Forums

Alright - I was walking through the forrest with a person and a curiois sight caught my eye. At a certain point there were three trees and a red wool binded around them. Also, it was not only rounded around the trees, the string, it was also interwoven between the trees in an irregular pattern, many times, it seemed. Now, my first thought was that it was a binding spell for something and someone, and I said to the person who was with me that this thing must be removed. He tore it with hands, but decided to tie a piece around my left wrist.
What have we done?
I don't know much about magic spells and I would appreciate some help?