Yellow Birch (Betula alleghaniensis)

Yellow Birch (Betula alleghaniensis), a.k.a. Swamp Birch, is native to northeastern North America and it's the largest North American species of birch. Its scientific name means "Birch of the Alleghenies," referring to the dissected plateau along the west side of the Appalachian's Ridge-and-Valley province. It can reach an age of 300+ years in Adirondack old-growth forests while one in Allegany County, NY, measured 439 years old in growth rings. 

The bark on young trees is smooth and some shade of brass, bronze or light copper with horizontal lenticels which are pores for exchange of gases with the atmosphere. As it grows, the bark begins peeling and curling in horizontal strips. (The one above was growing in Old Forge, NY, Oct. 8th, from my archives.) As the trunk matures, the bark darkens and cracks into ever-larger flakes, although thin branches may still have yellowish-brown, shreddy bark.

Yellow Birch seeds cannot penetrate leaf litter, so they germinate on mossy logs, decaying stumps and cracks in boulders. When it begins on wood, the birch is left standing on stilted roots after the base rots away. On boulders, its roots snake across the surface and down the sides to reach soil. (The one below [detail above] was growing in the Adirondacks beside the Moss Lake loop trail, accessed from Big Moose Rd., NW of Eagle Bay, New York, Sept. 25th, from my archives)