There may well come a time when you’ll want to build a small fire for cooking and want it to be as invisible as possible. Here is how some of the Plains Indians used to do it.
Start by digging a hole about a foot across and a foot deep. Next, dig a smaller hole a foot to a foot and a half away from it, angling it down to tunnel into the bottom of the first hole. Ideally, place this second hole toward the prevailing wind currents. The hole/tunnel should be four or five inches across.
Build your fire at the bottom of the main hole. It shouldn’t be all that large, maybe six inches high or so. The secondary hole will funnel air right to the bottom of the fire, making it very hot.
The hotter a fire is, the less smoke it will generate. If you build your fire under a tree, the branches will help disburse any remaining smoke.
You can adjust the heat somewhat by partially covering the vent hole with a large branch or a couple rocks. A cooking surface can be improvised by laying green sticks across the top of the fire hole, allowing you to place a pot or pan on them.