Water. Something both myself and my friends forgot about.

We solved the soil/earth problem by saying plants derive nutrition from rocks themselves, but completely forgot about water. Granted, elves do not sleep nor defecate, but they need to eat and drink. As all other races do.

As for climate zones, I don't mean the horizontal splits already present, but vertical. Would there be colder/warmer areas on the same depth? Or would they all be uniform when it comes to temperature?