Take the 2-minute tour ×
The Great Outdoors Stack Exchange is a question and answer site for people who love outdoor activities, excursions, and outdoorsmanship. It's 100% free, no registration required.

I watched a documentary "Man vs Wild" which showed the TV presenter Bear Grylls collecting wood and starting a fire. He somehow always manages to keep his campfire burning until dawn. How does one know how much wood to collect such that it is adequate to last throughout the night? Is there a certain method of arranging the wood pile consisting of broken branches and twigs to maximize the period of combustion?

share|improve this question
13  
I think the primary method employed is the "TV producers and staff keep it going while the camera isn't running" method. –  whatsisname Feb 3 '13 at 18:07
5  
Bear in mind that leaving a campfire burning unattended overnight increases the risks of starting a wildfire (a major problem in some parts of the US), and may be banned wherever you're camping. –  DavidR Feb 3 '13 at 19:01
    
When building a campfire, if you set the logs further apart they get more air and burn faster. If you set the logs closer together, they get less air and burn slower. –  theJollySin Feb 7 '13 at 16:19
3  
A better ethic would be not to burn so much wood. Leave No Trace is a really good philosophy. –  Ben Crowell Apr 28 at 4:18
1  
@BenCrowell you might consider a human corpse a trace as well... Of course you are right - you should not do that for fun. However, its good to know how to do it if you ever need it (for survival, not to impress your friends) –  Paul Paulsen May 15 at 8:28

4 Answers 4

up vote 18 down vote accepted

It's difficult to tell exactly how long wood you've gathered will last you, unless as an expert you can gauge an accurate estimate due to the type of wood, weather conditions and other contributing factors (theoretically possible, but above my ability level.)

However, there are different ways of constructing a fire, and one in particular is designed to burn for long periods, such as overnight, without requiring any maintenance or fiddling about through the night (if done correctly.)

This is known as a pyramid fire:

Diagram of pyramid fire

You place two logs parallel on the ground to start with, then place a row of smaller logs perpendicular and on top of the original two, then another row perpendicular and on top of that row, and so on. You then light the fire at the top, and instinctively quite bizarrely the fire will then burn downwards (as each level becomes hot enough to ignite the layer below it.)

Image taken from here.

share|improve this answer
3  
The trick to a long lasting fire is to limit the oxygen to it. Your pyramid stack would do the opposite. You'd get a really roaring fire for a relatively short time for the amount of wood used. Also I suspect Bear regularly attends to the fire during the night. There is a lot of stuff they don't show you. I like Survivorman better. Les does things ordinary people can do (Bear is a former special forces guy), and it's less staged. –  Olin Lathrop Feb 3 '13 at 17:46
2  
Les Stroud is the man. :) Definitely prefer him over Man v. Wild, simply because it's real - he doesn't have a safety camp right around the corner. It's just him, with one exception where the lawyers stepped in. –  Don Branson Feb 3 '13 at 20:18
2  
Thanks for the informative link. I think this is a plausible solution if the fire is lit on top. The rate of combustion may somewhat be controlled since the air can still be cool below the flames. This is provided that the spacing between the logs is small enough to prevent burning material from falling to the bottom and lighting up the whole pile. –  Question Overflow Feb 4 '13 at 8:45
5  
@OlinLathrop This method does work! I know it seems counter intuitive and looks identical to the fire used to create lots of embers quickly for cooking on (Log Cabin fire). The difference is, this fire is burned from the top down (heat rises) and the other (faster) burning, burns from the bottom up. –  RichardAtHome Feb 4 '13 at 15:56
5  
Hard wood (maple, oak, walnut, etc.) will burn longer than soft wood (pine, etc.). –  furtive Feb 4 '13 at 21:53

To get a long lasting fire, you have to limit the cumbustion somehow. Think embers as apposed to much flame.

Wood stoves are specifically engineered to allow you to control the rate of combustion. This is done by controlling the air intake to the fire, which limits oxygen, which limits the combustion rate. A wood stove can be built nicely sealed, so the biggest problem is providing enough oxygen to keep the fire going.

In the wild, this is much more difficult as you don't have a nicely sealed fire box with a single air intake you can control. The best you can do usually is to emulate a fire box with rocks and stuff up some of the openings with mud and the like. Still, there will be more oxygen than necessary to just keep the fire alive. There is little alternative to keeping a supply of wood ready and feeding the fire periodically if you really want to sustain a fire.

However, consider whether a sustained fire is really necessary. You can build something with at least somewhat limited air intake, give it a supply of relatively large pieces of wood, and surround it with lots of rocks. Even if the fire goes out, the rocks will stay warm for quite a while. A better strategy is to not require a fire all night long, especially if you are in a place and conditions where the fire could escape if you don't watch it.

share|improve this answer
2  
+1, esp for the comment about fire escaping. In many camping environments, an unattended campfire is banned by park policies because the risk of causing a forest fire. In some dry areas (esp. the American West) the risk of wildfires is so great that campfires may be banned entirely. –  DavidR Feb 3 '13 at 18:54
    
I have accepted berry120's answer because I think the air intake can be somewhat controlled by spacing the wooden pile close enough such that the inner pieces of log do not come into contact with a fresh supply of air to sustain combustion. Thanks for the suggestion of using rocks to store heat :) –  Question Overflow Feb 4 '13 at 8:52

Additional to the other tips and warnings I would like to mention one special tecnique I found in the book "Outdoor Praxis" by Rainer Höh.

Basically it consists of some kind of reflector fire, but the reflector will feed the fire instead. You would stick two or more thick, maybe even green, branches in the soil to support the reflector. Make sure to incline them away from the fire - while this makes the reflector less effective it allows self-feeding. Now pile your firewood up reclining onto the support sticks. Make/move your fire close to the reflector so the one at the bottom starts to burn. While it is burned up, the pile of wood will slip down, allowing the next branch to burn. This works probably best with wood 5-10cm in diameter. Smaller ones will burn to fast, thicker ones wouldn´t start burning easy enough.

Please note that this needs some practice and doesn´t garantuee that the fire will burn overnight. Still, its better than nothing. If you want to use it for staying warm its perfect, because you can stretch it and it has at least a little reflector.

Illustration (not quite what I am suggesting, since this reflector here isn´t meant to burn and the support sticks would be way to thin, but its similar):reflector fire

Image taken from www.survivalistssite.com

share|improve this answer

In one of the series of Survivorman the Les Stroud has put into fire the whole fallen pine. A very thick trunk will burn for a long time. Generally, the thicker the wood the longer it will burn. A thin branch will last a few hours, the fire will not be big, but it will nevertheless give heat.

Unfortunately I never recorded it, but as far as I remember a very thick branch was burning for a few hours. When it is cold, you wan't sleep the whole night, you would wake up often and you can adjust the campfire then. It's the way Bear Grylls probably manages that, if not helped by the camera crew ;) He almost always make shots in dark saying how cold it is and how bad he sleeps :)

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.