My son in law recently purchased a home in Orange County, NY, where the bases of a number of mature (1-2 foot diameter) Oak trees were covered with soil from the basement excavation. Supposedly covering the base of the trunk isn't good for the tree.
The "foot", where the trunk reaches out, is covered in almost every case. From what point do you measure, and how much soil is acceptable?
If he digs away the soil and builds a retaining wall, how high, and how far away should it be from the trunks?
Any other recommendations?