Silver Birch roots

Tree repotted very recently, still in oversized pot.
2016 will be the 8th year since it was born as seedling in 2008. Quite spectacular.
Just a 'fait divers', with a picture of the roots with a carved hollow, and a picture of the trunk base.
The tree is between 30 and 40cm high right now. It has a few years to go to build a better ramification. Next year maybe it will get a proper bonsaipot.