I am no expert but I think tress could go up to EF4 damage. I remember seeing tree damage in Andover,KS, Moore, OK, Harper, KS, and Parkersburg Iowa where not only was the trees completely debarked but also shredded down the center. I dont think there were even stumps even remaining. I am seeing trees in Tuscaloosa that are looking comparable. This tornado was at least an EF4 and no less. It is very obvious how violent this tornado was.