Mulching or mastication, whatever you call it, solves several big problems. First one is grinding up the trees means you don't have to physically pile them up for burning. With 16 acres, that's a lot of grapple work. Second one is the mulching gets the stumps to a level that they shouldn't interfere with mowing. Having 16 acres with stumps or holes everywhere would be a pain. Third is the mulching process leaves mulch behind to prevent soil erosion instead of raw dirt that can erode. Fourth one is the job gets done over a couple of days by a machine that can handle this kind of work. The OP won't be tearing up his tractor and spending all his free time cutting trees, moving them into a pile, and then having to take the risk of a fire getting out of hand burning the brush piles.