not much.. especially trees... die from pruning.. no matter how bad the pruning was ...

and.. with no insult to the root mass ... you might be surprised how fast it can regrow ...

you may have to remove multiple trunks.. if you wish to return to a single trunked tree ...but that might not be until your fall ...

i dont know aussie flora ... and i am presuming thats where you are ... this is mostly just general tree info ...

and i am presuming it was not treated with a stump killer when cut ...

just fyi .. usually location and a pic help us.. help you ...

ken

Im not sure i understand.. you said at first that he will die? And then you said he wont?..

I think you have misunderstood what Ken meant. He said that ‘not much’ will die from pruning ie it’s unlikely that pruning will kill your tree.