I hope it would be the latter though, but it may not be, I guess we'll see if it's mentioned in Fallout 4 or not. Choose any location in the scrolling list - its icon on the map will be highlighted by a red. View the locations of all marked places, bobbleheads, and unique items on the map.
So I think it would either be killing him, or spreading him more. The game takes place in the year 2277, 200 years after the Great War, on the East Coast of what used to be the United States. Killing him would be the easiest choice because it wouldn't effect anything big really an you wouldn't need to mention it again in the future. The Tree Father Birch suppressing Harold choice is just selfish for him and pointless, and is pretty unkind to Harold compared to the Laurel choice. But at the same time could make things almost too perfect for the Capital Wasteland, and Fallout is a lot more morally grey sometimes. It's great for the future of the surrounding wasteland in the long run, and Harold is obviously okay with it because he's staying alive for a great reason and it really does seem like a Harold thing to do, so those are a plus for it being canon. Personally, I'd really like it to be the Leaf Mother Laurel spreading more plant life to the wasteland choice I think it's the best one of course, but I'm not sure if that would be the canon choice.
