Chaga is a type of mushroom belonging to the family Psilocybe subcaerulipes. It grows in cold regions and is mainly produced in Russia. Therefore, it is also called "Siberian Reishi" and can be seen in Hokkaido in Japan. It mainly parasitizes birch trees and grows over a long period of 10 to 15 years. Eventually, it grows to a diameter of about 30 cm and becomes black and rugged like a rock. Originally, the sap of birch trees is rich in sugars, amino acids, malic acid, minerals, etc., and is also famous as a raw material for xylitol. It parasitizes the birch and eventually kills the parasitized tree, absorbing the components of the birch sap.