Hi - We are adding approx 8 inches of dirt to our lawn to build it up higher. Currently we are on the river front and have 2 large willow trees and a cedar tree we want to save. We know that putting this amount of dirt on the roots and up to the tree would be detrimental but wonder what else to do. Does it work to build a box around the base of the tree and not fill that area?? any help would be much appreciated.
You could build a box like that, but I'm not sure you need to. If they are really large trees I don't think you will have a problem. Just pull the soil away from againt the trunk until it all settles in.
Both trees have a good tolerance for soils with low oxygen so 8" probably won't be a problem. In the case of the willows, there roots will probably be will established in the new soil within a year. I second the recommendation to keep the soil away from the tree trunk though.
