The tree that popped up in your base should be caused by using the map in version b199, that already has been generated in version b197.
If you're playing on a dedicated server, you might solve the problem by deleting your actual map data from your saves.
You can do so by starting the "game launcher" via steam, then go to "tools", click onto "clean game settings", check the box for "game data", check the box "explored maps from other servers", check the point "all maps" and click onto "clean".
I am sorry, if I messed up any described words above, that may be called otherwise in the english version of the launcher - I'm using the german one.
I hope, I could help you and others aswell.
Cheers,
Darehitorimo