Betula alleghaniensis — Yellow birch, old-growth fallen tree.

• Within the Tionesta Research Natural Area of Allegheny National Forest, in Wetmore Township, McKean County, Pennsylvania.
• The exposed, stilted roots have grown from the stump of long-ago fallen tree.

• Remote and difficult to access, the research area protects an old-growth forest of hemlocks, white pines, and northern hardwoods. It and the adjacent Tionesta Scenic Area form one of the largest tracts of old-growth forest east of the Mississippi River.

• The forest has had its share of disturbances--deer overbrowsing, encroachment from oil and natural-gas drilling, and the destructive May 1985 tornado. The hemlock woolly adelgid has not yet been detected here; however, beech bark disease has killed many trees.

• "Despite the disturbances, the forest is magnificent. It was late in the day when I visited, and I had time to explore only a small portion of the forest. Will make a return trip."