Putting a low stone wall around tree
I live in central Florida... sandy soil. This past March I had a mult-trunk River Birch tree put in our front yard. The tree is doing great.
Right now I have a 5' diameter circle of Cyprus mulch around the base.
The other day I saw where someone had put a 2-tier stone ring around the base of their tree. It was the fake concrete stones like you'd get at Lowes. I thought it looked good.
My question is; if I did the same, can I add 4" of top soil or potting soil over the existing dirt that covers the roots?
In other words; I'd remove the exist mulch, put in the wall... it would be 10" high with a 2" thick cap - then add 4" of soil and the rest with mulch to bring it up to the top of the wall.
I was told when I put the tree in, to not add much, if any soil over the top surface of the root ball.