Does Chaga Harvesting Harm Birch Trees? - AlaskaChaga

Does Chaga Harvesting Harm Birch Trees?

With chaga growing in worldwide popularity, many people who are new to alternative medicine are curious as to how this little mushroom works. While native Alaskans and Siberians have cultivated and used chaga for generations, the explosion of chaga into worldwide consciousness is relatively recent, and there is much that is still not known about the mushroom. While most people are aware that chaga grows on birch trees, more environmentally-conscious consumers might be wondering if chaga harvesting harms the trees themselves.

The answer is no, provided that the harvesting is done right. While strip-mining chaga from trees can cause long-term environmental damage and stock depletion, ethical chaga harvesters have a series of practices they follow to protect birch trees and allow the environment to maintain its natural equilibrium. Here is how chaga harvesting can affect birch trees and how chaga can be sustainably harvested.

Does Chaga Harvesting Harm Birch Trees?

As most are aware, chaga mushrooms grow on the sides of birch trees in the northern hemisphere, though they can sometimes be found on other types of trees. Chaga naturally grows across a wide swath of the northern hemisphere, as far south as Turkey and the northern states of the continental U.S., but chaga from these regions cannot be harvested because it lacks nutritional value. Only chaga harvested from subarctic and arctic climates contains the nutrients that make it worth consuming in the first place.

Chaga is identifiable as a large black mass growing on the sides of birch trees; this mass is called the sclerotium, the tough exterior that protects the chaga’s internal tissues from outside contaminants. First-time chaga pickers sometimes mistake tree burls for chaga, but the crucial difference is that chaga is a mushroom that grows on the tree, whereas tree burls are part of the tree trunk itself and are usually the result of a disease or some kind of defect during the tree’s growth.

Chaga generally latches onto a tree during its early years of growth and eventually penetrates beyond the trunk into the interior part of the tree, leeching nutrients in order to sustain itself. Chaga is also capable of leeching sap from a tree due to its deep connections, which is part of the reason why chaga can only be harvested in winter, as running sap during the warmer months flushes out the chaga’s nutritional content.

While it is possible to remove an entire chaga growth from a birch tree, doing so is dangerous and ill-advised due to the fact that it will leave a large hole in the tree trunk. Trees are slow to heal severe injuries to their trunks, and a gaping hole is a perfect vector for diseases that can kill the tree. Chaga mushrooms are tied to the health of their host trees; if the tree dies, the chaga dies with it as it no longer has any resources to consume.

To prevent this, ethical chaga harvesters will only remove part of the sclerotium, taking special care not to remove any of the parts that are directly attached to the tree. This prevents diseases from infecting the tree and also allows the chaga to regrow over time. This also helps preserve the chaga supply in the area, preventing harvesters from having to go further and further distances in order to harvest chaga over the years.

Another method of sustainable chaga harvesting is to avoid picking chaga mushrooms that are too young. Chaga takes a long time to grow, and smaller, younger deposits can grow into larger ones if left untouched. Additionally, trying to take a piece from a small chaga mushroom can result in the entire mushroom being removed from the tree accidentally, leaving a hole in the trunk. Many chaga harvesters measure the age of a mushroom by using their outstretched hand and laying it on the sclerotium; if any part of their hand touches the trunk itself, the chaga is deemed too young and is left alone.

Much of the harm to birch trees in the context of chaga harvesting is not done by harvesters themselves, but by pollutants in the air. Trees absorb smog and other contaminants given off by factories, cities, cars, and other human developments, and these contaminants not only harm the trees, they infect the chaga and make it unsafe to consume. Because of this, chaga harvesters will typically head to extremely rural areas that are far removed from civilization and the pollution it generates.


Chaga has been harvested by humans for thousands of years; indeed, the medicinal use of chaga goes back before the advent of written history. During this time, humans have developed methods of harvesting that protect trees and prevent depletion of chaga stocks. Given the increased amount of pollution in the world due to industrial civilization and the growing popularity of chaga worldwide, it is understandable that some people would be concerned about chaga harvesting’s effect on the environment.

While there is no way to prevent unscrupulous pickers from engaging in unsustainable harvesting practices, as a rule, chaga harvesters are conscientious about the need to protect the environment. By not harvesting entire chaga mushrooms and leaving smaller mushrooms along, harvesters are able to keep trees healthy and alive and ensure that there will always be enough chaga for everyone.

Comments 0

Leave a comment

Please note, comments must be approved before they are published