Panaracer Trailrakers are brilliant in the snow or mud and very grippy on wet roots and rocks
They have all the grip of a pair of greased wet socks on roots, in my personal experience. I was riding with these yesterday (no other bike available) and was astonished at just how terrible they were on roots, and how easily deflected they were on off-camber sections. On loose rocks they were, if anything, worse.
I’ve got about four pairs, which I’m going to get ride of. The bloody things are never going to wear out, and other tyres are available which are a load better.