A Trench fire is simply a fire built in the bottom of a trench. In situations where you are forced to use poor quality wood and when cooking is made more difficult because of windy weather conditions, building a trench fire is best.
Start by digging or scraping a rectangular trench that’s length runs in the same direction that the wind is blowing. This will help assure a proper draft.
The trench should be about a foot deep, two or three feet long, and anywhere from 6 inches to a foot wide. Make the windward end deeper sloping upward to a shallow end where the wood can be fed into the fire.
Line the bottom of the trench with a layer of rocks. This will protect the fire from damp ground and radiate heat. You make your fire on this layer of rocks. You can also use rocks to bank both sides of the length of your trench leaving the ends open to take advantage of the draft. These rocks will create a support should the ground become loose and the sides fall into the hole.
If the trench is wider than your cooking gear, you may have to use green sticks to create a base to cook on. Rest the (pot, pan, etc.) on the deepest end of the trench.