Just what us woodworkers dread- bits of hidden metal buried for decades in a tree trunk, to be revealed by a snapped saw-chain when cutting firewood- [ boy, do they fly! ] or a set of precision planer blades exploding in your face. A couple of months ago I was planing some sycamore and as the piece disappeared into the thicknesser I caught a glint of metal. Argh! Too late to stop the machine, I dodged to one side but nothing happened! Inspection of the piece revealed 3 beautifully planed 9mm lead bullets!
Yes I would say that it has been there a long time too.
My next door neighbor has a similar setup, a square sodium light hanging from a pine tree, with the electrical cable hanging into the air and a plug which plugs into a floodlight on his house.
The light has been there probably 20 years and it still works and is slowly falling apart. The new owner who bought the house 6 years ago is a contractor and has left it just like it was. -- Another neighbor had old light wires grown into her trees that she cut out with a knife. And some trees in my yard had ceramic ring like insulators in them.