Is felt an environmentally friendly fabric?

I never really thought about it, but I don't think I would consider it too environmentally friendly, since it starts out as wool or cotton fibers and then is manipulated into the actual felt fabric - either mechanically or chemically. Either way, seems like a lot of effort. Unless you put a spin on it that the original wool and/or cotton fibers were going to be thrown away, but then were reused by being made into felt.