In This Guide
Birch polypore (Fomitopsis betulina) is a bracket fungus closely associated with birch trees. It is widely distributed across the UK and much of the Northern Hemisphere, where it grows on dead or weakened birch wood.
It is one of the most recognisable tree fungi. Its smooth, pale surface and rounded shape make it easy to identify. It has a history of practical use and has been the subject of modern phytochemical study.
Fomitopsis betulina is a wood-decaying fungus that causes brown rot in birch trees. It breaks down cellulose within the wood, leaving behind a brittle, brown residue.
The fruiting body develops as a thick, rounded bracket attached directly to the trunk. It often appears on standing dead trees or fallen logs. Individual brackets may persist for months, gradually hardening with age.
The species shows a strong host preference and is almost exclusively found on birch.
Young specimens are soft and slightly spongy. Older ones become tougher and more brittle.
The species name betulina refers to its association with birch (Betula). It was previously classified as Piptoporus betulinus and is still often referred to by this name in older literature.
Archaeological evidence links birch polypore with Ötzi the Iceman. Fragments of the fungus were found among his belongings, suggesting it may have been carried for practical or medicinal purposes [1] .
Birch polypore is not considered a culinary mushroom due to its tough texture and bitter taste.
It is sometimes prepared as a decoction rather than eaten directly.
| Part Used | Season | Key Preparations | Notes |
|---|---|---|---|
| Fruiting body | Autumn–winter | Decoction (tea) | Tough texture, bitter taste |
Historical records describe it being:
These uses are documented in ethnobotanical literature but vary by region and period.
Laboratory studies have identified compounds such as betulinic acid derivatives in F. betulina. These have shown antimicrobial and cytotoxic activity in vitro, though clinical evidence in humans is limited.
Evidence for medicinal use remains largely experimental. There is no strong clinical evidence supporting its effectiveness as a treatment.
| Compound Class | Found In | Biological Activity |
|---|---|---|
| Triterpenoids (e.g. betulinic acid derivatives) | Fruiting body | Antimicrobial and cytotoxic activity in vitro |
| Polysaccharides | Fruiting body | Investigated for immune-related effects in experimental models |
Birch polypore is not considered toxic, but it is not typically eaten.
Its toughness and bitterness make it unsuitable as a food.
What is safe:
What to avoid:
There is limited clinical data. Avoid use during pregnancy or alongside medication without professional advice.