I've used several different styles, 12"x12"x16' Oak being most common. Buy them out of Mississippi, 5 mats to a load. Very heavy. In Vietnam we used Philippine's Mahogany or Teak. I've used Southern Pine as well, didn't last for crap! Marsdon Matting works OK, light and strong, expensive too. Several types of polyester fabric are available, not as supportive though, without several inches of dirt or gravel on top. Used Cedar logs in Michigan, some Maple, Ironwood, and Poplar too.