One of my greatest mentors went over with a tree. The thing uprooted out of nowhere. He landed on the underside with it and suffered some bad injuries.
I've said this before and made plenty of book worm tree scientist types angry when saying it but.....
A tree will screw your life up in an instant and I don't care how much you know, read, saw and studied, you might not see it coming.
Trees show us a lot of warning signs, but they hide just as many.