The Pro Chip 310 takes 23 HP to operate so this one should be about the same. The flywheel in it takes care of the loads and it takes longer to wind down than a 30" mower with the heavy brush blades. 30 HP would be better though.I think that's at least Cat 1 3 point and a 540 PTO. It could be Cat 2 lifting arms too. Be willing to bet it requires north of 25 hp at the PTO to run it chipping larger material.
It is a neat setup. I've only seen one other like it on a tractor in NH. This one is on my '45. A few more pics of it here- http://www.mytractorforum.com/showthread.php?t=221689This is the first that I've seen a starter like the one in pic #3. It's pretty ingenious.