 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 31 @,@ 000 square miles ( 80 @,@ 000 km2 ) 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 to build homes , barns , and ships , and cleared the land for agriculture . The demand for wood products slowly increased and by the time of the American Revolution the lumber industry had reached the interior and mountainous regions of Pennsylvania . Lumber thus became one of the leading industries in Pennsylvania . Trees were used to furnish fuel to heat homes , tannin for the many tanneries that were spread throughout the state , 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 . 
