It's not all that efficient, but I'm new to this whole renewable resource thing. I had to restart a few times due to screwing up the cobblestone generator, but it seems to be working now.
On the far left, you can see the water for the cobble generator, which also irrigates the farm and runs a water elevator to a lower "safety net" floor. The farm has both melons and pumpkins growing, keeping in mind that dirt is a premium here. The bottom two levels of dirt are gone, and this is basically it.
On the right is the tree farm. Four squares of dirt with plenty of space for trees to grow big and strong.
The structure I'm standing on is my attempt at a "pasture"; grassy dirt floor, lots of light, wooden walls and ceiling, and I used some bonemeal to make grass and flowers grow. So far however, it remains empty. Some advice would be helpful.
Behind me is a bridge leading to a floating sand island. I already looted the chest over there, but I'm not touching the sand until I can build a catching platform underneath. At the far end of the bridge, it's just dark enough that monsters can spawn, though they can't see me until I move closer and most of them simply wander off the edge. Still, being able to grab the occasional piece of string or bone is always nice.
Next project: a monster farm. Enclosed and dark, and really high so monsters that fall off simply die from impact damage.
