Let the trees on your map spread over time similar to real vegetation
Mods introducing new content into the game.
Map generation and terrain modification.
Not sure if this is a bug or by design - Trees will grow through paved areas (refined concrete, refined hazard concrete). I was under the impression that trees couldn't do that.
Screenshot: https://steamcommunity.com/sharedfiles/filedetails/?id=2756568658
Not sure which version of factorio and the mod you are using. Do you have any mods installed?
Trees cannot in fact grow on tiles, which name contains the string "concrete".
Sorry for the late reply - I've been playing some other games.
Factorio is always the latest version as it's updated through Steam. Yes, I have many other mods installed.