Marshy sections of Jackson, Monroe, Wood, and Clark counties produce large quantities of Sphagnum moss, a major but little known state resource. Because Sphagnum can hold twenty times its weight in water, it is invaluable for keeping plants and nursery stock alive in shipment. It is also used in hydroponic gardening, for air shipment of flowers, and, because it is sterile, in surgical dressings and in seed germination to prevent fungus attack in seeds. In the central wetland marshes, Sphagnum replaces itself after harvest and is ready to be pulled again every three years. Harvest seasons run from spring until marshes freeze in the fall, and more than three hundred thousand bales are pulled annually for shipment all over the world. No other state produces Sphagnum commercially.