Birch bracket fungi on a fallen birch tree.

Abernethy Forest, Scotland, August 2023

Birch polypore (Fomitopsis betulina)

This amazing fungus has been used for thousands of years as medicine for the immune system, as antiseptic bandages, as tinder, and even to sharpen razors.

It has a number of incredible properties, including being an antiviral, antifungal, anti-inflammatory, and anti-fungal. It also contains betulinic acid, which can cause the destruction of cancer cells while not affecting healthy cells.

The one in the first picture is the perfect age for harvesting - young, not yet tough, and not yet opened out into a large hoof- or shelf-shaped body.

I dried out these young ones on a sunny windowsill and will be using them to make tea.

Birch Polypore (Boston, MA)

>>Fomitopsis betulina

Parasitic fungi that grows exclusively on weakened birch trees and causes brown rot. The fruits can last over a year, and it is eaten by Otzi the iceman to cure intestinal parasites.

Found growing on dead birch tree

Observed on: February 24, 2024

.•*o🧚‍♀️°•.°*𝓼𝓮𝓪𝓽𝓼 𝓯𝓸𝓻 𝓯𝓪𝓲𝓻𝓲𝓮𝓼*°•.o°🧚.*•

I mentioned birch polypore, Fomitopsis betulinus, in a different post the other day, and I thought this species deserves a post of its own because it’s a very interesting species particularly from an ethnomycological perspective. I don’t see this species often, but I’ve noticed it more frequently in the last couple years. I think this is because birch trees locally have been very stressed and experiencing dieback lately on account of climate-change related heatwaves and subsequent bronze birch borer infestation. Birch polypore attacks weakened trees and kills them within a few years, meaning the trees in these photos are doomed. 

It’s also a very pretty fungus, in my opinion, with a soft, suede-like upper with fawn dappling and a creamy spore surface. Someone other than me pulled these ones off a tree! I’m really not sure why, because this species doesn’t have any current ethnomycological uses, so maybe they were just curious and wanted to look at it. 

This species was one of the fungi carried by “Ötzi the Iceman,” a Chalcolithic man murdered in the Ötztal Alps around 3230 BCE, whose body was found in 1991. 

Ötzi carried a bit of birch polypore on a strap, and researchers think he likely used it to combat a whipworm infection from which he was suffering. Birch polypore used to be used as a dewormer; it is a laxative itself, but would often be combined with even stronger laxative materials. He also was carrying some Fomes fomentarius, tinder fungus, which was, as its common name suggests, usually used as tinder. 

In more recent times, dried birch polypore was used to sharpen knives, giving it its other common name, razor strop fungus. Some folks still use it for this purpose today, and as tinder just like Fomes fomentarius, but right now that’s more of a novelty practice you’ll find in bushcrafting classes than anything else.

Fallen birch with the typical polypore.wood dwelling fungi.

Fomitopsis betulina. Birch Polypore, old, likely last year’s growth.

Birch Polypore or Razor Strop #fungus

Piptoporus betulinus, once dried and used to sharpen razors and knives. Picture taken March 15. #nature #naturephotography #woods #mushroom #fungi #birchpolypore #razorstrop

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Fomitopsis betulina (the birch polypore) and Fomes fomentarius (the hoof fungus) growing on a dead birch.

Abernethy Forest, Scotland, August 2023

Birch polypore (Fomitopsis betulina)

Throughout the summer, both in Scotland and back in Cambridgeshire, I made it a mission to find and dehydrated large amounts of birch polypore - a very common and easily identified fungi that, while it is technically edible, its benefits are far better enjoyed via a tea. I've been drinking this once or twice a week all winter and am so happy I took the time to build up a store!

Thin Walled Maze Polypore (Boston, MA)

>>Daedaleopsis confragosa

Parasitic fungi that causes white rot

Old fruits found growing on a fallen birch tree alongside old mossy maze polypores

Observed on: March 17, 2024

The same tree from a different perspective