 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 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 . 
