That looks like a buckthorn [spit!] killer!
Since they're relying on mass and speed to shave the tree off inevitably they'll hit one that won't shear. Then what? Over the handlebars!?
I started building something like that for my Waldon but I didn't get any more mass buckthorn [spit!] removal jobs. Mine was like a comb with narrow V teeth, about 4" at the big end and about 15" long. Mount as many wide as the front of the tractor and pull the buggers out.