I come across bracket fungi all the time during my inspection work with trees as they are a serious problem with the decay of the roots, and main stem of many trees. many species of these brackets can be manufactured into amadou, the most referred to being the horses hoof fungus - Fomes fomentarius. Although great in number they are rather small and difficult to extract the trauma layer. A good alternative are the Ganoderma species. You wont find them as often unless you look for them most days, but when you do, you get a bumper crop.
I used a small section of a much larger specimen for this preparation. the rest is still feeding off the decayed stem of a Beech tree. You often find Ganoderma on older Oak specimens too.
Outer cuticle and tube section removed to leave the trauma layer.
I then boiled up a litre of water with two handfuls of hardwood ash, which was then strained through muslin into another container to remove some of the fine particulate, but retain some potassium in the solution.. I've not tried this separation method before but it seems to work a little better on the end result. The little man of the house donated the supplies.
Then back on to simmer with the fungus pieces added. Lacking a campfire on this occasion so the stove came out to play during the day, and I sat him on the woodburner during the evening. Quite useful for a long controlled simmer. It had a good soak in the solution for over 24 hrs. several of which were hot, topped up now and then with a splash of water.
Then I flattened the sections with the baton...
...and left to dry, massaging them now and then to leave them supple like tanned leather.
This batch goes up a treat with very little effort and should last a while.
My favourite way to light fire.