Berkenzwam / Birch Bracket
Piptoporus betulinus, commonly known as the birch bracket or razor strop, is one of the most common polyporous bracket fungi and, as the name suggests, grows almost exclusively on birch trees. The brackets burst out from the bark of the tree, and these fruiting bodies can last for more than a year. Technically, it is an edible mushroom, with a strong, pleasant "mushroomy" odor but a bitter taste. It is said to have medicinal properties, and the velvety cut surface of the fruiting body were used as a strop for finishing the finest of edges on razors. Dried specimens have also been used as tinder, and this fungus was carried by "Ötzi the Iceman" – the 5,000 year old mummy found in Tyrol.[1]
It is a necrotrophic parasite on weakened birches, and will cause brown rot and eventually death, being one of the most common fungi visible on dead birches. It is likely that the birch bracket fungus becomes established in small wounds and broken branches and may lie dormant for years, compartmentalised into a small area by the tree's own defence mechanisms, until something occurs to weaken the tree. Fire, drought and suppression by other trees are common causes of such stress.
In most infections there is only one fungal individual present, but occasionally several individuals may be isolated from a single tree, and in these cases it is possible that the birch bracket fungus entered after something else killed the tree. These fungal "individuals" can sometimes be seen if a slice of brown-rotted birch wood is incubated in a plastic bag for several days. This allows the white mycelium of the fungus to grow out of the surface of the wood. If more than one individual dikaryon is present, lines of intraspecific antagonism form as the two individual mycelia interact and repel each other.
Berkenzwam / Birch Bracket
Piptoporus betulinus, commonly known as the birch bracket or razor strop, is one of the most common polyporous bracket fungi and, as the name suggests, grows almost exclusively on birch trees. The brackets burst out from the bark of the tree, and these fruiting bodies can last for more than a year. Technically, it is an edible mushroom, with a strong, pleasant "mushroomy" odor but a bitter taste. It is said to have medicinal properties, and the velvety cut surface of the fruiting body were used as a strop for finishing the finest of edges on razors. Dried specimens have also been used as tinder, and this fungus was carried by "Ötzi the Iceman" – the 5,000 year old mummy found in Tyrol.[1]
It is a necrotrophic parasite on weakened birches, and will cause brown rot and eventually death, being one of the most common fungi visible on dead birches. It is likely that the birch bracket fungus becomes established in small wounds and broken branches and may lie dormant for years, compartmentalised into a small area by the tree's own defence mechanisms, until something occurs to weaken the tree. Fire, drought and suppression by other trees are common causes of such stress.
In most infections there is only one fungal individual present, but occasionally several individuals may be isolated from a single tree, and in these cases it is possible that the birch bracket fungus entered after something else killed the tree. These fungal "individuals" can sometimes be seen if a slice of brown-rotted birch wood is incubated in a plastic bag for several days. This allows the white mycelium of the fungus to grow out of the surface of the wood. If more than one individual dikaryon is present, lines of intraspecific antagonism form as the two individual mycelia interact and repel each other.