From an on-line dictionary:
"To shred (waste wood, for example) by machine."
I'll modify that by noting that I do some work at a factory that has machines that are referred to as "hoggers". They turn square wood into largish dowels (about 1 1/2"). The purpose of these machines is not to shred (as implied by the definition), but they do shred as they work. I have heard the term most of my working life, and it means to quickly remove mass quantities. It applies to both wood and metal (and more, I suppose).