There is so much confusion about Chaga especially when it comes to understanding exactly how this unique fungus reproduces. The fact remains that mycologists and scientists still don't know for sure, but can only speculate, on the sex life of the Chaga Mushroom. This is due largely because to actually find a fruiting body of Inonotus Obliquus in order to study is incredibly rare; dare we say, it can even be considered the 'Holy Grail' of Mycology. What has become known as Chaga is in fact, a sterile non-sexed conk and not a fruiting body. For years chaga was considered a member of the polypore family of tree rot fungi, but has recently been re-classified under hymenochaetales in the Basidiomycetes genius. Which kinda makes sense as fungi in this genius are Homothallic (have both bits and are...masters of their own domain ;-)
How does The Chaga Mushroom reproduce?
One to two years after the host tree has died the chaga fungus will begin to form a large network of tubular pores hidden underneath the bark of the dead host, beginning just above the chaga conk. This network of pores can spread several meters along the vertical span of the tree and remain hidden from view until ready to sporulate.
Outer plates are formed by the fungus around the Cambrian layer which harden to such density that they curl and force the outer bark of the tree to burst open to reveal the ripened fruiting body that was hidden underneath. Chaga is aptly named Inonotus (to penetrate) obliquus (an angular shift in degrees) because of the fungus penetrating tree wounds to attack and feed upon the heartwood; and the angular tubes that contain its reproductive spores are slanted 20-30 degrees upward towards the sun. Mycologists believe this is to enable spore dispersal allowing wind currents to carry spores to infect nearby damaged trees. Ironically, it is almost at par to the angular declination of the Earth relative to the Sun.
Another theory exists that because the soft tubular pores of the chaga's fruiting body are so rich in enzymes macro-nutrients, chaga's fruiting body makes itself nutritionally 'attractive' so that beetles and flying insects simply cannot resist their favorite food-stuffs; kinda like an invitation to a FREE you can eat buffet. Chaga's fruiting spores then have a chance to 'hitch a ride' on their dinner guests allowing insects to disburse spores on their behalf. As a result, the fruiting body of chaga is usually devoured within a week not leaving much evidence behind. It is rumored that Chaga can sporulate as many as 2 to 3 times within 7 years after the host tree has died.
Birch Tree with resupinate pore surface of the sexual reproductive stage of innonotus obliquus
End stage of the reproductive cycle of Inonotus Obliquus; soon after the fungus fruits, insects, beetles and larvae consume the nutrient rich network of fruiting tubular pores.