I usually put an diagonal roof over the fire. maybe a wall on the bed side of it just to keep the smoke out. The diagonal roof stops the rain, and two makes it feel like a chimney. I'll do a tall one, then a short one connected to it, just to fit my own imagination that it won't work unless I do it that way. Might be a waste of wood, but trees and branches are everywhere.

Edit: Oh yeah, angle it so it doesn't close the roof. Gotta leave that one spot open so the smoke goes out.