Watch out for this if you try it in a city, because you could run afoul of bylaws and angry neighbours. In Surrey, British Columbia, a family tried doing this. They had piled up bark mulch and manure, and one of their neighbours complained to the city, which then told the family to remove the piles under Surrey's Unsightly Premises Bylaw. I don't know the outcome (I haven't found any articles after this point) but if you start piling bark mulch in your back yard, make sure you don't piss off your neighbours doing it.

http://blogs.vancouversun.com/2013/10/03/surrey-takes-action...