Originally Posted by DVS Hardscaper
never place any material (soil, gravel, sand, etc) above the crown of a tree.
And technically speaking how high or at what point on the tree would that be? We are only talking 8 inches height here, and I would leave a nice (say 2-3ft outside of trunk all the way around) area cut out around the base of the tree to let air and moisture get to it. Just put some mulch or a groundcover in that area.