Betula pubescens Betula pubescens Betula pubescens (syn. "Betula alba"), commonly known as downy birch and also as moor birch, white birch, European white birch or hairy birch, is a species of deciduous tree, native and abundant throughout northern Europe and northern Asia, growing farther north than any other broadleaf tree. It is closely related to, and often confused with, the silver birch ("B. pendula"), but grows in wetter places with heavier soils and poorer drainage; smaller trees can also be confused with the dwarf birch ("B. nana"). Three varieties are recognised and it hybridises with the silver and dwarf birches. A number
Beech bark disease to spread to the south and west. The first case of beech bark disease in the United States was reported in 1929 in Massachusetts. By 2004, the disease had spread as far west as Michigan and as far south as western North Carolina. For beech bark disease to occur, two components are required, an insect and a fungus. The beech scale insect, "Cryptococcus fagisuga", is invasive to North America and is host-specific, feeding exclusively on beech trees. It can be observed on the trunk and limbs of the tree as woolly, white tufts that will later develop into broad strips.