Birch Polypore

Welcome back to Mushroom Monday, your weekly look at PEI’s fascinating fungi. We’re staying with the Polypore group for another week to look at a species that can be found even during this drought: Birch Polypore (Fomitopsis betulina).

Birch Polypore is second only to Red-belted Polypore as the most frequently reported mushroom on PEI. While it is legitimately common, it’s also easy for even the most novice naturalist to identify, and it sticks around long after the fruiting body – the external Polypore we see on the tree – has expired (main photo).

This fungus can grow on any of our Birch species but is usually a decomposer of dead trees rather than a parasite of the living. It’s one of the Brown Rot Fungi, digesting cellulose and leaving behind lignin, and so makes important ecological contributions to forest soils and their ability to store carbon.

These distinctive Polypores start out as cream to tan coloured brackets with smooth, leathery tops, often with a few cracks (top right photo). Underneath is a smooth, white pore surface that’s a bit raised at the outer edges and doesn’t change colour when bruised or cut (bottom right photo). As the mushroom ages, both top and pore surface become darker, dryer, and rougher, and that raised outer edge becomes more of a rolled rim.

Birch Polypore has a long history of traditional use: a piece of this mushroom was found on the mummified body of a person who died more than 5,000 years ago! (It’s believed the Polypore was being used to treat intestinal parasites). Modern research supports the antibacterial, anti-inflammatory, antiviral, anticancer, neuroprotective, and immune-boosting properties of various Birch Polypore extracts.

This mushroom is too tough to be edible but can be used in other ways. In addition to being antibacterial and anti-inflammatory, Birch Polypore is styptic (it helps stop bleeding): peeling off the outer layer can provide a useful dressing for minor wounds. It can be cut into small pieces or sliced and used fresh or dried for tea. Thinly sliced, fresh material can be soaked in alcohol to make a tincture, or in oil over low heat for use as a skin treatment.

Birch Polypore can fruit spring, summer, or fall when conditions are right, and I see this mushroom pretty much anywhere there are Birch trees. Now that you know what to look for, I’m betting you’ll be seeing this interesting member of PEI Untamed!