If you are traveling in wooded areas in the Southern part of the US or anywhere there are pine trees, you can leave your tinder at home. There are always dead pine stumps in these parts of the wilds that make great tinder. The heart wood, also known as lighter pine or pine knots, are pure sap wood. Once you locate a piece (easy to know by the smell of turpentine and the sticky feel after it's cut) just make a fuzz stick from the sap enriched stick and use your ferrocium rod to get an instant blaze. This stuff burns regardless of the weather conditions and lasts a long time.
Another thing we look for are bird or animal nests since there will be dry material even in wet conditions. Ferroicum rods will blaze this stuff quickly.
The scaly bark from Cedar trees works well also. Just ball it up in your hand and shred it into fine pieces and strike your rod into it. Cedar bark bundles are what we use a lot to nest coals from bow drills or char cloth from true flint and steel.
Regardless of what anyone will tell you, I haven't found any material in it's NATURAL state that will catch a spark from TRUE flint and steel methods. Even cotton balls whether dry or soaked in vaseline will not catch and hold a spark from a piece of flint found on the ground and a piece of striking steel such as the back of your knife or C-steel.
Ferrocium rod sparks will start a blaze in a lot of tinder materials since the sparks are so much hotter, but true flint and steel needs charred material to hold a spark. The only exception to this is a tinder fungus that we have used but difficult to find. I'm sure there may be others that are not common to our neck of the woods also.
As a side note, if you are interested in true flint and steel, then cotton char cloth is not the best method for this from what we have found. We use charred punk wood since it will hold a coal much longer and catches a spark just as quick - and in the woods there's a ton of punk wood to be found from rotting trees.
Bottom line is if you have a ferrocium rod, cigarette lighter, flame thrower, etc. then you should be able to start a fire in the woods under any condition without any tinder brought in. Forget about true flint and steel though unless you have charred something previously. Even good char cloth will fail you under high humidity. You will have better luck with friction fire if you have nothing but a knife.
Getting a blaze is actually the easiest part of the fire building process. The problem with most fire builders is not knowing how to build a fire after the initial blaze. Gathering proper materials and processing them before the blaze makes success every time. Trust me...I'm a pyromaniac
Jeff
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Randall's Adventure & Training
jeff@jungletraining.com