RAH --I work with wood for my profession. They make a product that has copper in it for a wood preservative and fungus killer. One of the best things out there right now for it's purpose. Then throw into the mix that the algae killers that are recommended here are copper based. So, if copper is bad for these things, why wouldn't it have a bearing on plant life further up the eco-chain?
I am not being argumentive in bringing this up, I am just trying to learn.
BGK -- Yes, it could have as much to do with that you girdled the tree. Some trees have a tougher resistance to that type of thing than others. We have all seen an example at one point or another where a tree grew around something and not die. So, possibly the copper did give that one last death blow.
