Prior to the arrival of William Penn and his Quaker colonists in 1682, up to 90 percent of what is now Pennsylvania was covered with woods: more than of eastern white pine, eastern hemlock, and a mix of hardwoods. The forests near the three original counties, Philadelphia, Bucks, and Chester, were the first to be harvested, as the early settlers used the readily available timber and cleared land for agriculture. By the time of the American Revolution, logging had reached the interior and mountainous regions, and became a leading industry in Pennsylvania. Trees furnished fuel to heat homes, tannin for the state's many tanneries, and wood for construction, furniture, and barrel making. Large areas of forest were harvested by colliers to fire iron furnaces. Rifle stocks and shingles were made from Pennsylvania timber, as were a wide variety of household utensils, and the first Conestoga wagons.