Before I discover replacable parts, I don't know where the rubbers are. Now, if I keep clearing forests and jungles, will I accidentally clear the potential rubber sources as well? Has anybody seen rubber appear in grassland/plain tiles that were once forests and jungles?
The locations of all resources are preset. There's a constant chance they'll be depleted... BUT... in the case of rubber...
There's no chance it'll be depleted. It just starts somewhere on the map and stays there the entire game. Clearing forests/jungle or mining or whatever won't make a difference at all.