I would rent a decent size dozer with teeth on the bottom of the blade that rips up anything to about 6" below the surface & have it done in no time. Or build an attachment like it for your bobcat. The problem is you may never use it again.
' below the surface & have it done in no time
You can lead people to knowledge but you can't make them think.
“Firearms stand next in importance to the Constitution itself. They are the American people’s liberty teeth and keystone under independence.” – George Washington