Wood doesn't break down under landfill conditions either, at least not on human time scales. But wooden objects do biodegrade within human time scales if just

Wood doesn't break down under landfill conditions either, at least not on human time scales. But wooden objects do biodegrade within human time scales if just left in a meadow. The same is true of polylactic acid objects. Neither wooden nor PLA objects break down in a home composting system like orange peels do, but both biodegrade much faster than e.g. polystyrene.