During the Catoctin Iron Furnace's peak years from 1859 to 1885, more than 300 woodcutters cleared chestnuts, oaks, hickories, and other hardwoods from the company's 11,000 acres and from private lands like these. In late winter and early spring, colliers burned about 11,500 cords of wood to make the 18,000 bushels of charcoal needed to produce the furnace's yearly output of 1,000 tons of pig iron. Every 25 to 30 years, cutters cleared all but a few of the fast-growing chestnuts and other hardwoods up to 10 inches in diameter, and the forest was cut again when crews returned with axes and saws to gather a new supply of wood for the collier.