How to conveniently label trees

To uniquely label special and noteworthy trees in the woodlot and to track them with a blog they need to be labeled. The label has to be durable enough to last many years. I thought that a plastic square cut from a Javex bleach bottle, or joghurt tub might do. After all these plastic bottles are known to last for up to 30 years in a landfill. The identification information would then be marked on it with an indelible marker. I noticed however that the permanent markers will fade completely when exposed to the sun after only one season. So instead I found the aluminum cat food can lid quite suitable and there is a plentiful supply. Using a punch set - bought from Princess Auto and hoping one day to find a use for it - I could punch the tree code on the lid. I could then tie this to the tree trunk while it is still small with a bit of wire or screw it into the trunk when it is larger. Aluminum corrodes very slowly and will last much longer than 30 years and more like 50 years.