Fire from wet log
This was actually one of the summer camp challenges in outdoor organisation I was at kid. It was called fire from a wet log. You were supposed to start a fire using only:
- knife
- axe
- matches
- piece of log that has been under water for 2 days
This assumes that the center of the log isn't completely damp. The solution was:
- chop down half of the log into big splinters
- use knife to make thin wood shavings of the rest of the log. Make lot of them to be really sure. The thinnest the fastest they burn, the more energy they release per second.
You now have a small piece of wet log, splinters and shavings. It's best to first pile shavings together, ignite them and only then start adding the splinters - this way you add them where they should be.
This small fire will already be able to ignite wet branches, provided they are dry inside.
Brushwood on tress (spruce and fir)
Spruce and fir trees ALWAYS have dry tiny dead brushwood on the bottom side of their branches. This burns really fast and hot - it's better than paper and leaves cinder that produces additional heat. Usually, the brushwood on the ground near these trees is also reasonably dry.
Birch bark
The white coverings of bitch trees burns insanely for some reason. Be careful to only harvest the tom layers not to damage the tree. Bark on dead branches works just as well.
Resin
Use small stick to harvest some resin to serve as a candle when starting the fire. This can save you precious matches. Resin burns hot and long. Do not use knife to harvest the resin - you would damage the tree and you will have problems cleaning the knife. Some sources claim resin dissolves in alcohol, but I really recommend not contaminating anything with it.
Use fire to dry more wood
This is probably obvious, but do not forget to put logs and branches around the fire (far enough to not ignite though) so that they are dry by the time you want to put them in. We used to make second barrier after stone barrier of wood. Shoes can go on the wood and wood can be used to prevent them from falling in the fire.