You're welcome!
QuoteA question: the roots' displacement looks more than just heightmap based. They almost look like geometry. Is ther something special?
It's just a normal-based displacement, nothing fancy here. The ambient occlusion layer accentuates the contact shadows around the roots, small stones, etc. In the color shader, ao was used as a mask to distribute a layer of dirt around those, too. So maybe it's just a case of the visual cortex filling in missing information.
Fyi the base color is srgb but ao, height, and roughness are linear. So you'll need to use image maps and set the color and displacement data accordingly.