Works similar to a rocket stove. The diagram explains it pretty well.
ADVANTAGES:
The fire burns very hot.
Less firewood is needed than conventional fire methods.
Food or water will cook / boil faster.
The efficiency of the burn creates less smoke, which means less visibility (if relevant)
This method is particularly useful and manageable if it is very windy compared to other methods.
The fire burns below the surface of the ground which shields the flame from being seen, especially at night.
Tips
To further diffuse any potential smoke (if that’s a concern), build the Dakota fire hole near the canopy of a tree to help avoid detection.
Choose an area with favorable soil. Avoid rocky or rooted areas.
Be wary of soil which may ooze with moisture or fill with water.
Be sure the fire is out when you’re done! Be cautious that the fire is not smoldering roots (or peat) beneath the surface – which could potentially ignite afterwards.
Directions
1. Dig a hole about 1ft in diameter and 1ft deep. It’s helpful to enlarge the bottom of the pit by several inches to accommodate longer pieces of firewood than the surface hole diameter. This will be the chamber of the fire pit.
2. Dig the airway tunnel beginning about one foot away from the fire chamber hole. The diameter of the airflow hole should be about six inches and will angle down towards and into the bottom of the main fire chamber. Ideally this airflow hole should be upwind from the main fire hole.
3. Fill the fire pit partway with kindling and light the fire. Gradually add sticks to build a stronger fire. The fire creates a suction which is drawn into the airflow tunnel, resulting in a much hotter and efficient burning fire.
