Roger that on the holes. Never a shortage of nearsightedness in construction trades.Most of the holes are there because the edge of the patio is on a very steep hill, and there was concern there wasn’t enough load-bearing soil there. So, a small retaining wall was built along the
to fix that, and these holes were also dug as an additional measure - I assume so that to more of the weight of the concrete slab would be away from the edge of the hill.
Interestingly, we got estimates from a lot of contractors (some big expensive companies and some smaller shops), and pretty much all had the same approach for the hill / slope (retaining wall + holes).
And...not a single one mentioned anything about not being able to get close to the tree. Perhaps one of the others would have brought that up during the actual project (obviously the company we chose didn’t), but none brought it up during the estimate phase.