Chaga is a natural medicine that is unlike other medicinal mushrooms. That’s because Chaga isn’t actually a mushroom at all. Chaga is a “sterile conk” or canker. It grows on the side of trees, primarily Birch, and is induced by a fungus called Inonotus obliquus. This makes it unique in comparison to other medicinal fungi as it contains bioactive compounds from both the fungus and its tree host.
Chaga has been used traditionally in Russia, Siberia, Canada, Alaska, and many Circumboreal cultures. It is traditionally used for many different purposes, including digestive issues, cancer, viral infections, and skin problems. Today it has become popularized for its high antioxidant content, immuno-modulatory effects, and the treatment/prevention of cancer. Studies also suggest it could help with diabetes and other chronic health conditions. While there are some very promising effects attributed to Chaga, a lack of human clinical trials still places uncertainty on the efficacy and proper usage of Chaga.
Natural History Of Chaga
The ecology of Chaga is a tale of two antagonists, a tree host and a parasitic fungus. Together they form a “phyto fungal” canker composed of both plant and fungal tissues. Cankers, just for reference, are tumor-like growths that you can see on the sides of many trees. They are most often induced by bacterial or fungal pathogens and are diverse.
Chaga is produced by a fungus called Inonotus obliquus which an overwhelming majority of the time parasitizes Birch. Although rare, Chaga has been reported from Alder, Beech, and Maple amongst others. It is estimated that Chaga only grows on less than 0.1% of Birch trees.
Chaga is pretty easy to identify, especially when growing on Birch. Identifications can get tricky when we add other tree species into the equation, which can be quite challenging for amateurs to identify. They are spherical and have an outside that is black charcoal and crusted texture. They can grow from the size of a fist to the size of your head, and even bigger. The inside of the canker is fibrous, woody, and with a distinct yellow coloring. They may occur high up in the canopy.
It’s interesting to note that there are approximately 100 species in the genus Inonotus. Some of these form “sterile conks” or cankers, but the majority form a-typical polypore fruiting bodies.
Inonotus obliquus is considered a parasite and causes white rot on the heartwood of the trees. It infects its host via spores that enter wounds on the bark. Evidence suggests spores are likely dispersed by insects. The most common hosts are birch trees between 30 and 50 years of age.
Once infected, the tree and the fungus produce an intertwined plant/fungal biomass that slowly grows on the tree. These cankers can grow for more than 30 years and the fungus can eventually result in the death of the host. It is assumed there must be intricate phytochemical “warfare” occurring within these cankers, with trees producing defense compounds and Inonotus defending itself from them.
The “sterile conk” that we know as Chaga is often wrongly regarded as being a solid mass of mycelium termed sclerotium. While there is still a lot of research needed to properly identify the characteristics of these growths, research shows these cankers are a composite of sclerotial mycellium and plant tissues. Emerging research suggests that the mycelial biomass within the cankers could be as low as 10% or lower.
While the Chaga canker is not a mushroom, it doesn’t mean the Inonotus obliquus doesn’t produce mushrooms. They produce mushrooms once in their life cycle at the end of their host’s life.
These begin growing beneath the bark, forming a crust-like pored structure that can be up to 4 meters in length along the trunk. Once mature the bark often withers away exposing the inconspicuous fruiting bodies. These are also relatively short-lived as they are devoured by insects, who are assumed to be responsible for the dispersal of the spores. Seeing the actual fruiting bodies is rare and infrequently documented.
The distribution of Chaga is largely limited to northern latitudes. In North America, Chaga reaches its southern distribution in the southern Appalachian mountains. Its range extends north following the mountain range and then becomes widespread in the Northeast USA and Canada. It is also found in the Canadian Rockies, British Columbia, and Alaska. Other than in Alaska, Chaga is not found in the western United States.
Chaga is widespread in central and northern Europe. Its distribution is largely concentrated around the Baltic countries and Russia. Chaga has been reported from the UK, Netherlands, Germany, Denmark, Poland, Finland, Sweden, Estonia, Russia, Austria, and neighboring countries. Chaga is considered rare in western and southern Europe.
Chaga has been reported in China, Korea, Japan, and even Thailand. Analysis of the Thai Chaga has shown it contains a distinct chemical profile.
Sustainability of Chaga
Chaga is relatively scarce in nature and there are pertinent issues with its overharvesting. This is because when Chaga is harvested, foragers remove a vegetative structure that could take well over 5-10 years to grow. They are not like mushrooms which form ephemeral reproductive structures that are harvested.
This can not only greatly diminish the resource in heavily exploited areas, but it could negatively affect the lifecycle and future abundance. While Birch forests may seem abundant in some parts of the world, there is a growing demand for Chaga. The fact that thousands of Chaga products are listed on Amazon alone gives a legitimate reason for concern.
For this reason, it is best to find a provider of Chaga who knows the origins of their product and can ensure a sustainable harvest. We should also keep in mind that overexploitation of this resource could reduce its accessibility to those with medical conditions who want to incorporate it into their treatments. Many experts discourage and frown upon the use of Chaga if not used as part of a conscious holistic treatment for a medical condition.
Cultivation Of Chaga
True Chaga has not yet been cultivated on a commercial scale. Chaga products claiming to be cultivated are typically Inonotus obliquus mycelium grown on grain which does not have the same bioactivity as the wild canker. Experts generally agree that these myceliated products are not as effective.
The inoculation of host trees has been shown to be possible and successful. Since Chaga only occurs on less than 0.1% of Birch trees this technique has great potential and could be incorporated into sustainable forest management plans. This is an emerging practice that will still require time and research before it becomes commercially available.
Traditional Uses Of Chaga
It’s believed that Chaga has been used for well over 1000 years by traditional cultures in Europe and North America. The first account of Chaga being used in medicine dates back to the Persian physician and scientist Avicenna from the 11th century. While this record is repeatedly cited, it lacks verification. In the 12th century, there is a historical tale claiming that Duke Vladimir Monomakh of Russia cured a cancerous lip tumor using Chaga.
Indeed Chaga has been used in Russia since the 16th century for the treatment of various types of cancer. In Siberia, it’s also been used historically to treat tuberculosis, gastritis, stomach ulcers, and liver problems. The Khanty peoples of Siberia would ignite Chaga and once it was a fiery ember, they’d extinguish it in hot water. This water was then used for feminine hygiene post-birth.
Since the 20th century Chaga has been consumed as a cheaper alternative to tea for economically disadvantaged rural communities in eastern Europe. By 1955 the USSR Ministry of Health recognized the therapeutic properties of Chaga and it was included in the Soviet Pharmacopeia. Chaga also has a history of consumption in China, Korea, and Japan, although it’s not as prevalent as other medicinal fungi.
In North America, it is known that Chaga was traditionally used by the First Nations of Canada and the United States. Here it was used by the Cree people of Alberta, the Wet’suwet’en of British Columbia, the Tenaina of Alaska, and many other native communities. Its uses greatly varied, from the treatment of viral infections and pains to the use as incense, tinder, and even for ceremonial purposes.