This fabulous fungi growing on the fallen silver birch branch is a birch polypore, Piptoporus betulinus. It is a parasitic fungi that causes brown rot in birch trees, but continues to flourish after the poor tree has died.
It is also known as the Razor Strop Fungus; barbers used to cut thin strips off this leathery fungus to make strops to sharpen their cut throat razors. It can also be used as tinder to start a fire with a spark, it will then smoulder and hold the flame. In the Scottish Highlands it was used to start the fires to celebrate the festival of Beltane (now May Day). Two pieces of this fungus were found on the body of Ötzi the Iceman, who died in the Alps 5,300 years ago. Poor Ötzi was found to be suffering from whipworm parasites, the birch polypore is now known to contain ketones, terpenes and aliphatic alcohols which can act as anti-inflammatories along with polyporenic acid which is apparently effective against intestinal worms. Clearly Ötzi had yet to complete his medicinal course before he met his end. Amongst its many other uses it also acts as food and home to many species of insect.