Well, I went and read the entire thread - there do seem to be a few primitives who have an understanding of the way many trees work, but the majority of the chorus is singing 'sue the tree killers ! ' instead.
If you leave the tree alone, its well-established root system will generate a massive new canopy in just a few years, provided the tree isn't otherwise diseased. You will not have to wait 'decades' for it to happen. If you love that tree as much as you claim to, seal the cut areas and leave it be. You can thank me later.