Gidday guys - I am just wondering why the hedge / saplings or whatever need to be cut off at ground level (I realise the cows need a fair go) but what about the idea of yanking them out roots and all. It does depend on root formation & type of ground structure, but I have had a lot of success using a chain to choke around the trunk and yank it out with a Nissan patrol - it was a lot of fun (& hard work) but you can even pull out big trees if the roots & dirt let you yank them apart when the ground is at the just right level of saturation (everyone else is hunkered down in this sort of weather but it works well). A little levelling after and it stays clean without regrowth - has worked for me, but I also like the idea of a big spinning brushcutter on steroids. I have plans in my head for one for heavy duty grass & small regrowth and I reckon swinging hammers as you would have on a mulcher would be the go. Once you get to a reasonable diameter the chance of rotational imbalances mean things have to be pretty beefy to cope with the stresses and to also have mass to absorb some vibration.