Heavy duty forestry mulchers can clear up to fifteen acres of vegetation a day depending on terrain, density, and type of material. Forestry mulchers are often used for land clearing, right-of-way, pipeline/power line, and wildfire prevention and management, vegetation management, invasive species control, and wildlife restoration...More at the Wikipedia page.
Forestry mulchers and forestry mowers are often used for removing underbrush and invasive species, such as buckthorn and multiflora rose, in order to allow the rejuvenation of grasses and other food sources... Invasive insects such as pine beetles can also devastate forests, leaving behind rotting trees with diminishing timber value and that may become falling hazards if they lose their ability to stand up against wind...
Related: shredding a Volkswagen Beetle.
Via The Presurfer.