Thank you all for the advice. I've used copper wire for other trees and like it's holding power, but I've also read in multiple places that copper can stunt growth of plants. So I've tried to use aluminum mostly. Have any of you read about that?
Aluminum and Copper. Two different tools , separate uses in the right hands! One has better holding power, the other a softer impact for deciduous and easily marked species of conifers. With adaptation one can use either.
Copper can be more expensive and takes more skill to apply properly, less forgiving to changing ones mind.
As for killing the tree, perhaps you are thinking of copper in the shape and weight of an axe, it is less likely that aluminum will kill the tree if in the shape and weight of an axe. Way more effort required I would think! But then that is the way it works with wire as well, way more effort with aluminum ( thicker wire ) for. the same effect.