Yeah know, I could knock down a tree with my fist if I hit it enough over a period of time (a long period). Any realistic use of a mg would never "cut down" a tree unless it was small. I'm just a bit surprised you took the time to find a video of someone shooting down a tree...but hey.
I also believe that it is possible to tap of a round at a time in DODS, if not with the mg42, surely with the .30 cal. I'm also seriously doubting that DOD:S models multiple hits on one location to chip it away. I actually think that the garand and k98 do shoot through walls, I used to snipe a lot when I played source, and I think I remember hitting guys in houses. So really our pointless debate ist kaput.