Making and keeping a fire

A fire is prepared entirely before the first spark. Whoever lights first and looks for wood afterwards won't have a fire.

ACT

1. Gather everything before striking anything. Three separate piles, from finest to thickest, within reach while sitting. No lighter or matches: see Allumer sans briquet. A new fire dies in thirty seconds; that's less than the time it takes to fetch an armful.
2. Insulate from wet ground. A platform of green branches laid side by side, or dry stones. Wet ground soaks up heat from below and puts out the embers — the same conduction that chills your own body, described in Building an emergency shelter.
3. Build the structure around the tinder, not on top of it. As a tipi or a pyramid, with an opening facing the wind. The fuel should surround the flame without crushing it.
4. Light on the side the wind comes from. The flame is pushed into the fuel instead of being blown flat into empty air.
5. Feed it small and often. Only double the size of the fuel once the previous size is burning well. The universal mistake is smothering a young fire under a log too early.
6. Put a reflector behind the fire — stacked logs, a rock, a wall — and sit between the fire and the reflector. You double the heat you receive for the same amount of wood.

Be careful with stones picked up by a river or from waterlogged ground: moisture trapped in the rock turns to steam as it heats and can make it burst.

ADAPT

It's been raining for days and everything is soaked. Standing dead wood is drier than dead wood on the ground, which draws moisture from the soil. Low dead branches still attached to a trunk are your best source. Above all: a split dead trunk is dry at its core. Split it again, take the heart, and cut it into thinner and thinner splinters until you get shavings. In conifers, knots and the bases of dead branches concentrate resin; this fatwood catches even when damp and burns for a long time.

You only have green wood. It won't catch on its own. It can, however, dry above a fire that's already going: the first hour of fire then prepares the second.

The fire escapes the fireplace. See House fire: indoors as in vegetation, the smoke comes before the flames.

You need to stay hidden. What gives you away, in order of range: the smell first, the smoke by day, the glow at night. Smoke means incomplete combustion — damp wood or not enough air — so a well-run fire smokes little. A buried fire, a pit with a side air channel, hides almost all the glow, burns hotter, uses less wood and can be filled in within seconds. Placement matters more than size: a dip in the ground, a screen of vegetation, the far side of a slope.

The fire burned someone. Cool with water for twenty minutes before anything else: see Burns.

You want to be seen instead. Then the fire changes role and becomes a signal: Signaling and getting found covers the choice of smoke, location and timing.

You're settling in for a long time. Wood becomes your main cost in time and trips, and repeated trips wear paths that can be seen from far away. A camp is chosen on three criteria at once: water — see Making water safe to drink —, wood, and being able to stay out of sight. Two out of three don't hold for long.

You need it to last. A thick log laid on a bed of embers and half covered in ashes lasts several hours. The ashes limit the air supply and slow the burning without putting it out. That's what lets you find embers when you wake up.

UNDERSTAND

A fire almost always fails for the same reason: a stage gets skipped. There are three, each one only lights the next, and none can light the one after.

Tinder takes a spark. Dry, extremely fine fibres: shredded birch bark, crumpled dead grass, hemp fibre, cloth lint, thistle down, lime-tree bark fibres. This stage decides everything, and it's the one you always prepare too much of, because it burns in a few seconds.

Kindling takes a flame from the tinder. From the thickness of a match to that of a pencil. A foolproof test: a twig that bends instead of snapping cleanly contains water. It won't catch.

Fuel wood takes a bed of embers. Never add it before the kindling is burning well.

What governs this progression is surface area. A material burns through its surface exposed to the air, not through its mass. The same amount of wood split into shavings offers thousands of times more surface than a log, so it catches at a much lower temperature. Each stage brings the next up to its own ignition temperature. Skipping a stage means asking a flame to heat a mass it doesn't have the energy to heat.

Second principle, and it's counter-intuitive: a big flame is reassuring and heats almost nothing. It's spectacular because the wood releases its gases all at once, but most of that heat goes up with the smoke. It's the bed of embers that gives heat back, by radiation, for a long time, burning little and giving off no light. A useful fire is a low fire.

Third principle: it takes three things at once — fuel, heat and air. A dying fire is always missing one of the three, and in practice it's almost always air. A pile that's too tight smothers. A fire that smokes black lacks air. Spreading the logs two centimetres (about an inch) apart is often enough to revive a fire you thought was lost.