A fireplace is a construction that can be built on a floor inside a cabin.  It requires 35 stones to build.  A fireplace is required to create a heated room, which is required for smoking meat.  When wood is burned in the open, it stops providing heat when the fire goes out.  When wood stops burning in a fireplace, however, the embers continue to provide heat.  This keeps your cabin heated in the winter for longer using less wood. It requires 4 firewood to get started.