I looking at building a patio in the back yard. One problem is a rather large maple tree about two feet from the edge of one side and I get a lot of flack when I mention cutting it down. So I'm keeping the tree. What I need to do is change the edge near the tree and make it go around in a semi circle. I'm wondering how close I can come to the tree with the patio? Keeping in mind that will need to dig down six to eight inches to do my foundation.