[masraum]

Maybe it's not going to completely die. Maybe it's just "stressed". Maybe some branches will die but most of the tree will survive. Hopefully, Baz will chime in as he knows about plants.

I'd think that it was the gas co. We had someone come dig a huge hole in our backyard for something. I think it was a large sewer pipe, so the city. They dug a huge hole that was probably 8' long and at least 6' deep within 2-3 feet of a 30-40' tall oak tree, so they had to cut through a ton of the roots, and it died. I think the missus called the city and their answer was "sorry".

Good luck. Maybe it's not going to die.