Hi Digital Chocolate
You need to very clearly to explain the 6+ hour offline for regrow of trees rule ingame because this is a very unique feature only found in Galaxy Life.
I have not played any other game that reward players for being offline.
It is very, very, very, very, very, very unnatural for players to go offline to progress in a game.
Not all players are reading the forums so you need to give an ingame notification the first few times a player clears all the trees on a planet that he/she has to be offline for at least 6 hours for the trees to grow back.
Most players don't understand this and end up leaving the game because they can't find Star batteries.
This should be relatively easy to implement and you need to do it very fast before you lose too many players.