Hoof (tinder) fungus (Fomes fomentarius)
The hoof or tinder fungus is weak and wound parasite that grows preferably on older trunks of beech and birch trees, but is not completely unknown on conifers and deciduous trees. The semi-circular, relatively large fruiting bodies that sit on the sides of trunks are very conspicuous.
When walking in forests or parks, these fungi are very easy to find. As a weak and wound parasite, it never attacks constructional timber. It can cause intensive white rot and considerably reduces the resistance to breaking in infested trees.
How can you recognise the hoof / tinder fungus?
The hoof fungus infests older and weakened trees through wounds in the bark, damage to branches or points where branches have snapped off. The hoof-shaped mushrooms sit directly on the bark or on strong branches, too. Small groups of these fungi can often be found on one tree. The fruiting bodies can live for a number of years, are concentrically zoned and brown in colour, turning greyish-white later. Over time, they develop a hard outer crust and grow to sizes of 10 – 25 cm in width and up to 20 cm high. The pore layer on the underside of the mushroom is cream coloured to begin with but turns brownish with age.
Where does the fungus get its name?
Under the fruiting body’s hard outer crust, there is a soft velvety layer which used to be collected and used to make tinder. The material ignites readily and by hammering it flat and putting it into saltpetre, its flammability could even be increased. In earlier times, trade with tinder was economically important in some regions. The famous “Ötzi”, the iceman, discovered in the Similaun Glacier in 1991, carried with him a bow and arrows, a dagger, flint stones and of course tinder.