I have an old DR from 1994 that I've used to chop through a lot of stuff. Taking your time it will knock down 3 inch saplings and can be used to chew down small stumps. It will run through privit easy enough as long as its in that size range. This thing is belt drive with 1/4 inch thick steel blade being pulled by an old eight horse engine. I can't imagine what the 17+ HP models would do.
I have one of these I pull behind an ATV. If you go slow enough, it’ll cut just about anything up to 6 feet tall.
I’ve pulled it through all kinds of crap. Stuff that some people would think you could not get an ATV through.
I think mine is an 18 horse Briggs