Could Installers/Users please share their experiences with loop proximity to tree/roots. The book suggests no closer than one half the branch extremities, my rep suggests even closer.
how close have you trenched to a tree, with/without impact.
Joe

We've never gotten closer than half the branch extremities. The closest we've gotten is with a DX bore hole, though.

For a horizontal pit, my dad planted a tree last year over the edge of his pit, but it's not got deep roots yet. We'll have to wait and see if it makes it or not.

As far as getting closer, the risk is that the temperatures of the ground fluctuating from the ground loop will kill the roots of the tree. If the tree doesn't have to go yet, you could try it and see, with the owner full aware that the possibility is there that the tree won't continue prospering in the future...