I think it depends on the tree regarding soil out and away from the trunk.
In our yard, I wouldn't even add a 1/4 inch around my Arbutus (madrone) trees.
But around poplar and a few maples, I'd feel okay adding maybe 1/2 inch - preferrably in the lowest spots.
It's not just a matter of soil on trunks.
Roots exchange gases. They use oxygen and release carbon dioxide. Additional soil can interfere with that. |