The tree that just won't die!!

This tree (and another exactly the same) appeared from nowhere and started growing beside the burn in the garden. It grew to be quite big very quickly but it was an eyesore so it and it's companion were cut down.

Roll forward less than a year and the bugger has started to grow again!!

I've now lopped off all the growing bits in the forlorn hope that it will give up - but I very much doubt it.