The tinder fungus par excellence (Fomes fomentarius) has been used both to light a fire and to carry fire from one place to another. If we collect a carpophore in the field, dry it in the sun or beside a radiator and set the area where it was attached to the tree on fire, a spark of fire will run through it for hours; this is how transhumant shepherds carried fire from one place to another.
Tinder fungus on an alive poplar.
If we impregnate a piece of this dried mushroom in saltpeter, it will start to burn with just a little spark: this is the tinder fungus.
Possibly the best known mushroom for its traditional use, the mushroom of the tinder fungus, Fomes fomentarius, can be easily found in dead poplar wood along the river banks.
Its use as a hemostatic and healing product has been known since Roman times. For this purpose, it was used by burning it slowly on the affected skin. Today it is known that it has antibacterial properties and that this use was completely correct.
With the "fabric" of these tinder mushrooms, hats, shoe soles, and other things have been made. Thus you can make an elastic mushroom leather with multiple applications by leaving slices of the mushroom in a caustic soda solution for several weeks and then beating them with a hammer.
At an ecological level, let us mention that woodpeckers make their nests in the trees that have been parasitized by this fungus. This is because the wood is softer thanks to the fungus and it also gives warmth to their nests, through the fermentation process that it produces in the wood.