The pit that is left has been a big concern for a lot of our clients. One actually demanded that we fill the whole thing back in and rebury his tree again after he paid us to uncover it.
We start with the intial recommendation by explaining that there will most likely be quite a hole left around the base of their tree. Depending on the depth, we can slope it gradually back up to grade, build a retaining wall around it, or if they just can't live with the sight, suggest a pourouse material like river rock or pea gravel. We prefer not to fill at all and explain that even with a larger river rock and certainly with the pea gravel, there is additional maintenance involved in annual cleaning. Have you ever gone to your kids playground that was covered with pea gravel and seen the compaction that results when dirt and silt has been allowed to accumulate? Like cement.
The concern we hear most often is about the standing water that results after a rain or after their irrigation system goes off. We try to explain that this is not a problem because there is a period when the water soaks into the ground and the trunk tissue dries again, unlike when that area was covered with soil and would remain saturated with moisture.
Again it is a problem with education. As we are beginning to get to a point that people are calling us to inquire about root flare excavation, rather than our intiating the process, we hope to have less of a problem.
There have been trees that we have done that I have looked at and
!! We sure did it this time! With only one exception, in three years, I don't know how many trees, results have been positive.
Question... Have you done many Live Oaks? We have seen tangled layers of smaller roots above larger "traditional" root flares. Don't know why we only see it with these and not others. It appears typical for the Live Oaks that we have gone into. Would like to know more.
MIke have you gotten those kakis and loafers dirty yet ? 
