Birch Polypore (Razor Strop) (Piptoporus betulinus)
Survival and practical Uses.
Piptoporus is from the Greek piptein meaning “to fall,” and Latin porus for “pores.” Betulinus
refers of course to Betula spp., the birch upon which it commonly grows.
Wildcrafters may wish to note that forests rich in birch polypore and Fomes fomentarius are poor in Chaga (Inonotus obliquus), and vice versa. That is, it appears that once some fungi have set up home, others are less welcome. The wood decayed by the fungus has the distinct odor of green apples.
Known as kanbatake in Japan, it is sure to quickly join the ranks
of prized medicinal mushrooms.
Ethnobotanical Use:
This annual polypore was used as a razor strop instead of leather in Victorian times, hence one of its common names, “razor strop.” The fungi were cut into strips and nailed to wood with the pores on top, and the surface was powdered with siliceous earth. This was used by barbers, surgeons and others. Pacific Northwest lumberjacks made similar strops but did not powder the surface.In 1991, Ötzi the Ice Man, who lived 5,300 years ago, was discovered relatively intact in a mountain pass. He carried two walnut-sized pieces of birch polypore mounted on a decorated leather thong as well as the prepared context of false tinder conk (F.fomentarius). Dr. Luigi Capasso (1998) of Italy’s National Archeological Museum discovered that birch polypore is a powerful but short-acting laxative, and contains oils toxic to intestinal parasites.
“The discovery of the fungus suggests that the Ice Man was aware of his intestinal parasites (Trichuris trichiura) and fought them with measured doses of Piptoporus betulinus,” Capasso reports.
He continues, “The toxic oils in the fungus were probably the only remedy available in Europe” until thousands of years later. It is still used today in Italy and Poland to facilitate the excretion of parasites.
Like the other polypores mentioned in this article, birch polypore has an affinity for fire. It may be cut into small strips for tinder in survival packs. The polypore smolders very slowly and can be used to transport fire from one site to another. Beekeepers have used smoldering fruit bodies to calm their hives. The soft, flexible, and protective nature of the polypore makes it ideal for holding obsidian and other stone for flint knapping spearheads, hatchets, knives and other sharp instruments. Mycologist Paul Kroeger suggests the polypore may have been used to hold sharp objects used in fire making. At one time, it was used to polish tarnished silver and is used today in Switzerland to polish metal watches. Pieces have been used for sweat pads in hats and by Scottish Highlanders as packing for the back of circular shields or targets.
In parts of Britain, the context was cut into small strips as a styptic and as corn pads for the feet. It may be roasted until black and powdered as charcoal for application as an antiseptic to bleeding wounds. It cuts easily and may be used as a cork. It is much prized by biologists and taxonomists for mounting butterfly and insect specimens. The polypore was used traditionally in Bohemia to treat stomach disease and rectal cancer. Young, fresh specimens can be sliced and boiled in soups. After a few days of room temperature storage, however, the taste of its drying polypores becomes quite sour. Amateur mycologist and wildcrafter Chris Leifson cures slices of the polypore for six months when the typical cream white color turns golden bronze. The aroma is like bittersweet chocolate and is a nice addition to smoking mixtures.
Chemical Constituents
Birch polypore contains the following: Polyporenic acid A, 1,3-BD-glucopyranans, B ergosta -7,22-dien-3 (-ol, fungisterol, ergosterol, polyporenic acid A and C, agaric acid, dehydrotumulosic acid, ungalinic acid and tumulosic acid. It also contains 4-methylmorpholine-N-oxide, a methyl sulfoxide soluble glucan, piptamine, and various lanostanoids.
Research Cancer
The birch polypore fruiting body possesses anti-tumor activity, and early work found induced apoptosis in melanoma cancer cell lines (Shibata et al (1968). Betulinic acid and betulin are present in birch bark and concentrated in this polypore. Betulinic acid, a pentacyclic triterpene, destroys melanoma cancer cells without affecting healthy cells (Pisha et al 1995). A fraction of the dried fruiting body was tested, in vitro, against lung (A549), colorectal (HT29) and rat glioma C6 cancer cell lines. Decreased tumor cell proliferation, motility, and induction of morphological changes were noted, with no or low toxicity to normal cells (Lemieszek et al 2009). Work by Cyranka et al (2011) found cytotoxicity against colorectal adenocarcinoma cell lines. Kawagishi et al (2002) identified a novel hydroquinone with enzyme-inhibiting properties related to the formation of tumors.
