Man's ability to build fire is what brought him out of the caves.
Collect your fuel, kindling and tinder, always choosing the driest fuel possible. Most forests have downed branches, tree limbs and other fuel. The dry inner bark of fallen logs, old birds nests, wood shavings, pine needles and paper make great tinder for building a survival campfire.
Note: Build the fire a couple of feet in front of a rock face. The heat of the fire will be reflected by the rock, and if you sit between the fire and rock, you'll have heat front and back.
Kindling will be small dry twigs, pine cones, and dry bush branches. Always collect the driest kindling possible. If the outside is damp, shave it down to the dry inner part of the branch or stick.
Gather dry wood only. While hardwoods make the best, long-burning fires without sparks, your wilderness area may only have softwoods such as spruce and pine. Whatever wood is available will burn, just be aware that resinous woods will usually burn fast and throw sparks.
Remember: If you're in a pine forest, you will need to collect twice as much fuel.
If the branches you find are long and unwieldy and you dont have a chainsaw handy, grab the branch at the thickest end. Holding it like a baseball bat, whack it against a standing tree trunk. The pieces that break off will go flying, but you can amass a good collection of campfire-length wood in a very short time using this method.
Hopefully youll have matches or a lighter in your pocket, if not eyeglass lenses can be used to concentrate the sunrays to spark a fire. Flint and steel works great too. As a last resort you can rub two sticks together, just make sure they are dry and you have a bed of dry tinder close by.
Note: There is no dark as dark as a moonless night on top of a mountain...a perfect time to find a match in your pocket and a some dry wood at your feet.
Once you have the survival campfire going, itll then be time to think about building a wilderness survival shelter and finding food and water. Although shelter and water may be considered more important than a fire, as a human you are going to feel much better once you have a fire going. Not only will it provide warmth, but it will help keep away the wildlife. That fact alone will be a great comfort at night with sounds of movement in the underbrush just beyond the range of the light of the fire.
Hint: If you want to be able to see what might be lurking beyond the light of the fire, dont look directly into the survival campfire for more than a second or two. It will ruin your night vision and when you look into the darkness beyond the light of the fire, you will have to wait for your eyes to adjust.
For more on the survival campfire and other wilderness survival tips