Buried leaves reveal precolonial eastern forests and guide stream restoration

Red Oak (left), American Beech (center), Sweet Birch (right). These are fossil leaves removed from the Denlinger Mill study site. UNIVERSITY PARK, Pa. Sediment behind milldams in Pennsylvania preserved leaves deposited just before European that provide a glimpse of the ancient forests, according to a team of geoscientists, who note that neither the forests nor the streams were what they are today. "Milldams were built from the late 1600s to the late 1800s in Pennsylvania and other parts of the east," said Peter Wilf , professor of geosciences , Penn State. "We can't get information from historic records on what the area looked like before the dams because recording of natural history didn't really begin until the 1730s and was not detailed." U.S. census shows that by 1840, tens of thousands of milldams existed in the mid-Atlantic region. About 10,000 of these were in Pennsylvania.