Hey all, I have a canadian maple or acer rubrum???? i think that i purchased from a nursury to plant in my back yard. It was a 3m flemings tree, a few months after planting i noticed it had a borer hole half way up it. I sprayed it wit pesticide and got rid of the borer, but since then i've noticed that pretty much the top half is now dead.

The trunk is atleast a good inch think, maybe 1.5 inches, and was thinking of air layering half of the alive part and creating 2 trunks. Since the trunks are dead straight and nice and fat, i was thinking a broom style would suit, but i am just curious if there might be any precautions in making a V cut and leaving such a large area of exposed wood........or any other tips would be greatly appreciated
cheers,
Aaron