I don’t think that you should feel too guilty. Humanity does lots of stupid things and so long as we try to dissuade and prevent stupidity we can have a clear conscience - if regret that our efforts have failed.
Thankfully we avoid politics on UU (because politics tends to tear forums apart) but so very many of the actions associated with the UK’s second high speed rail project (HS2) amaze me in bad ways. I’m sure that environmentally damaging projects are happening all over the world - I very much doubt that the U.K. is the worst of offenders - but somehow the wilful destruction of ancient trees and woodland is a shameful act and particularly so as we have relatively little of it left. As for HS2 itself, well we don’t do politics here but if we did I wouldn’t be speaking in favour of this project. The cutting down of trees for wood (as a crop) can be a sustainable practice, but to cut down an ancient tree just because it’s in the way seems rather too close to an act of vandalism to me. One can but hope that the timber from this tree is used in some special way appropriate to its age and species.
And what will happen to the wood? There were old trees cut down on George Washington's property, and they were used for something worthwhile, I think. Yes, article below.