The problem I have with this is that it makes the dirt surface full of holes after all the trees get axed. I'd prefer a solution where the dirt node is maybe marked in a way that mapgen won't place another tree in the same location instead.

Can you also push the change to saveschems? I'd like to keep minetest-mods/saveschems in sync.

Yes i don't like the holes either, that was the reason i removed the root nodes a while ago. Hopefully some players will carry some dirt around to fill in the holes as they harvest.

And yes, i guess i 'clone' saveschems for my local copy. I will try to push changes.