Piptoporus Betulinus (Razor Strop Fungus)
by Mark Kneller

The picture shown is of a young fruiting body. The fruiting body starts as a ball, with a light brown mushroom colour, then it expands into a kidney or hoof shape bracket with a white underside and a light brown leathery top surface.

This is a stem decay fungi found almost exclusively on Birch trees (Betula). The decay is a brown-rot decay primarily attacking the sapwood, giving the sapwood a reddish brick colour, this eventually becomes a cubical rot. Once this has taken place the tree is very susceptible to wind through or just collapsing. Infection enters through broken branches or a pruning wound.

The pruning of Birch trees should not be carried out in the spring, due to the high flow of sap. If there are several small cuts or even just a few larger cuts the sap will continue to run, looking like water, and in some extreme cases the tree may bleed to death.

When the cuts continue to leak sap this can quickly turn to mould and attract fungal infection such as Silver Leaf and Piptoporus Betulinus.

The name ‘Razor Strop Fungus’ originates from the use of strips cut from the fruiting body and being used for the sharpening of razors. This fungus is inedible.

Mark Kneller
Mark operates as an arborist and trainer based in Kent and undertakes a range of work for both private clients and Local Authorities.

Mark is a qualified trainer offering NPTC courses in all aspects of arboriculture including the full suite of chainsaw modules and aerial platform training. He can be contacted on: 01634 244958 Email: mark@marksplants.fsbusiness.co.uk