I have used "Blue Tarps" from the box store...plastic sheeting and just about anything I can lay my stickey fingers on but, the best wood pile covering I have found is left over rubber roofing. It is heavy,black and does not rip or deteriorate from the sun.If it is doubled on the edges Gromets can be installed to use as tie-downs. Even if you have to buy it it will last for years.And if you don,t like black it can be painted with acrilic paint any color your wife wants.....just my two cents.
Mike
Mike