That makes sense. In my example where my tree sort of overtook and grew over the copper wire holding my tags, if was certainly oxidized because it had been out in the weather for 3 years or so before the tree absorbed it. It also originally was on top of the bark, so ever when the tree overtook the wire, there was still probably a layer of bark between the wire and the cambium or inner tree, even on the inside of where the tree grew over it (if you understand what I mean). SO your right now that I think about it…that is quite different situation from putting fresh copper wire on a bare tree with the bark removed.
This discussion is interesting to me because I have some kind of tree in my blackberry patch that I somehow let get to almost an inch in diameter (it did that in ONE YEAR!) 3 years ago and I’ve been fighting it for 2 years now. I can’t really dig out the roots without damaging blackberry plants and one of my posts. I also can’t use deadly sprays or poisons because it is inches away from several blackberry plants. So I have kept that thing cut off to basically ground level for 2 solid years and its still alive and well!!! I would have thought that if I kept it cut of at ground level so it could never make leaves for photosynthesis to feed itself, that it would starve within a few months. NOT SO. That thing has never had more than a few small leaves once in a while when I forget to cut it back for a couple weeks, and 90% of the last 2 years it hasn’t had ANY leaves. But I already noticed this spring that it is green, alive, and about to send out another shoot. SO I may try the copper nail thing!!!