This info may be known by most but it couldn’t hurt to review the basic of fire. Here are good firecraft links.
http://www.wildwoodsurvival.com/surviva ... index.html
Here is link that has wood burning characteristics.
Often people think that starting a fire is the only thing that needs to be understood for good firecraft. But learning more about combustion principals and characteristic of wood can go along way to making your fires more efficient. Survival is about efficiency and taking only necessary risks. I won’t go into every fire starting method as this has been hashed over more than the AK-47 vs. AR-15 debate.
1. The fuel.
In general wood can be separated into hard and soft wood. Softwoods tend to be Pine, Cedar and Spruce. Softwoods are conifers and are characterized by having needles year round and cones. Hardwoods are trees with deciduas leaves. They turn all funny colors and drop in late fall. Despite the names hard and soft wood do not always imply the density. Yew being an example of very dense softwood. But in general hardwood is often more dense. There is a near direct ratio between the density of wood and BTU out put aka British Thermal Units. For example Hickory, some types of Maple and Oak are very heavy (dense) and have much greater BTUs than Softwood like Eastern Pine. Softwood does have another component that can’t be ignored. Softwood sap. With conifers the sap is very flammable. It burns like plastic. This is no surprise being a resin. So softwoods will ignite easy and burn hot for a short time until the resin is burned off. The saying that Softwood is used to start fires and hardwood is best to hold fire is very true. Hardwood will burn much longer and coal better. Sometimes if you can find an old stump from a softwood tree that died naturally and was standing for years before it fell the core of the stump may contain FATWOOD. After the tree dies the resin will slowly settle to bottom. If you find a stump take your hatchet and hack away to the core. This wood will burn like OIL. The BTU’s are off the chart. It can ignite anything. I take this fuel and carry it around until needed. A little goes a long way. Softwood tend to spark more than Hardwood. This is an issue for the heated shelter.
Know your trees
Here are some leafs from my 3 favorite fuels. The all have good BTUs, Coaling properties and are fantastic for cooking.
2. Location of fire.
Generally your fire should be protected from the wind or with the prevailing wind direction away from you. Setting up your fire so that the heat is directed towards you is a big help. A cliff wall etc acts as a good heat reflector. You can build a fire ring. This takes energy and is often impossible in winter but the reflected heat acts a bit like a wood stove to increase the overall temperature of the fire. This can be a big help with wet fuel.
3. Wet and frozen wood.
Sucks but it happens. Wet wood has the same potential BTUs of dry fuel. The only problem is the water must be boiled out of the wood before it will burn. This takes a great deal of energy. Often wood is wet only on the outside. Take your hatchet (you have one right?) and split the sticks. It can make the difference between a failure or a hot blaze. Once you get the wood burning lay your fuel next to the fire to help dry it out. If you are using a wood stove place the fuel under the stove. Look for standing dead wood. If you can help it avoid picking your fuel off the ground. Break the wood and look for a good grain. Rotten wood has already been burned by bacteria and offers very little heat. It can even make the fire harder to start. Frozen wood is a terror. This happens when you get a radical temperature change. Rainy days followed by a cold snap. Bad news. You must split the wood or it will not burn. This is the time to crack out the fat wood or a healthy amount of Pine resin.
Some split sticks of black birch. After 4 inches of rain the inside of this standing dead wood was mostly dry. If possible carry a hatchet or tomahawk. This tool will earn it's keep.
Here I am using the heat from the fire to dry the fuel. Some may ask why not toss all the fuel into the fire? There is a saying: The Indian (Native American) sits by a smaller fire to get warm, however the Whiteman makes a blaze so hot that he is driven back into the cold. The classic jumbo blaze is wasteful. There is no purpose to a larger fire than is needed. You become a slave to it always on the hunt for more wood. The Whiteman’s fire has a place at Jellystone Park when you are drinking with friends. Survival on the other hand is about staying alive. The smaller "scout fire" is often enough and burns very little fuel. However if you NEED a bigger fire to raise your core temp than by all means do it
Here I am using a small Kifaru stove to dry fuel by placing the wood under the stove. The Kifaru small stove weights about 3 lbs and packs down stove and foil pipe to no larger than a medium sized lap top computer. The sticks are black birch. I often save a small amount of dry fuel for the next day if the weather looks unsettled.
Smoke is part unburned fuel, dust carried by the updraft and water vapor. If your smoke is pure white then it consists of more water vapor (boiled out of the wood). This is ok. If it has a hint of blue then it means poor combustion. Lots of fuel wasted and less heat.
You can cook food directly on hardwood coals. Yup just place the meat on the coals after the fire dies down. Nothing is cleaner than a coal. Plus it tends not to stick to the food. Do not do this with softwood fires. Do not cook over the flames of a soft wood fire. I always cook over coals never flames. Softwood resin can make you sick. It is ok to keep food suspended above softwood coals. Side note. A few trees like Laburnum anagyroides are toxic and should be avoided at all costs. Do not use this deciduas tree or any tree/plaint listed as poisonous for cooking. If you get sick just eat some charcoal left over from a fire. Yup not very tasty but can remove toxins and clean your system out. A real lifesaver because you will get sick from diet change and stress in a Bug out.
Here is an example of using hardwood coals to cook some trout. I started with some green black birch. Green is a term for live wood. Using my hatchet I removed the bark and sharpened the sticks. The process can be done with a knife or sharp rock.
The next step I burned down some Maple to coals and weaved the trout thought the sticks. Then I used a fire ring to support the fish 3 inches above the hot coals.
Cooked and very good!
This may all seem silly. When you are drinking beer and tossing wood pallets over a blaze with your friends why care? But survival is not camping at Jelly Stone Park. A good hot clean burning fire can last the whole night and not smoke you out. Poor fuel will kick your ass when you are down. Stumbling in the dark for more wood is ok at Jelly stone but is a big risk in a survival setting. Better to get some good clean long burning fuel a few hours before sun set. Don’t wait until dark. Get the most out of your Fire. Find the best location. You can even use rocks to store the heat. Just don’t take them from a stream etc. Wet rocks can explode. Wrapping these rocks in a towel makes them portable heat. Just don’t burn your hands. Place them up against your kidneys etc. Most of all your fire makes good company. Keeps the night terrors real or imagined at bay.