At least he was quick to sit up. Had he been really hurt, he wouln't be moving much. Still that is a lot to hit you when you are trying so hard to outrun it. Falling trees always are so much longer than they first looked to be.
Whoever was in charge of that is a frigging idiot. Same for any adults in the area. You're pulling a tree down with teenagers and bystanders standing around? Idiots.