If you are in an emergency situation and need a really easy-to-make rocket stove, look no further than a hollow tree stump.
A hollow tree stump is an amazing way to make an emergency rocket stove. If you've never seen one before, you really need to check them out. All you need to make this work is a tree stump which is at least partially hollowed out, and some kind of implement to make a hole at the bottom of one side of the stump. A bushcraft knife or hatchet should do the trick.
Take a look below at a hollow tree stump rocket stove in action (photo and video credit goes to Phil Wouters) and you'll get an even better idea of exactly how to make one yourself.
While you may not have an abundance of hollow tree stumps, chances are you'll be able to find one somewhere if you really are in a survival situation. Then all you need is a small bit of tender and small branches to have yourself an amazing fire. The stump might not last all night, but it should be good enough to offer some warmth and cook a nice meal.