I do this all of the time and My Tak TL140 will make short work of it. It will be about 3 times as fast as doing it with my KX 161 excavator. Both of those together with 2 operators is the best way to go.
When its cleared just use something to dig up the first six inches of the ground to loosen the rest of the roots left, Harley rake them up into piles, pick them up and your done. Perfect for ssed bed. There however will be a few small roots occasionally left sticking up but they will mow pretty easy.