A mushroom [almost] magic!

Do you know which mushroom is it?
I only grow on the trunks of Birch, but I am rare ...
I am a true natural anti-aging treasure, venerated in many civilizations for thousands of years ...
I have one of the highest concentrations of antioxidants in the plant world ...
I am one of the two main ingredients of the Saeve Care Patent ...
In Latin, my name is Inonotus obliquus ...
Who am I?
I am of course ... the Chaga!