Betula alleghaniensis aka Yellow Birch

Yellow birch, Betula alleghaniensis, is a large deciduous tree in the birch family. It grows wild across eastern North America. Its range runs from Newfoundland and Nova Scotia west through the Great Lakes to Minnesota and Manitoba. Farther south it follows the Appalachians to Tennessee and Georgia. In the south it keeps to cool spots: high ground, north-facing slopes and moist gorges. It is the largest native birch in North America and the provincial tree of Quebec.

In gardens it usually reaches 60 to 75 feet (18 to 23 m) tall, with a crown about as wide. Wild trees sometimes reach 100 feet (30 m). Young trees are dense and pyramidal. With age the crown becomes rounded and irregular. The tree grows slowly but lives a long time, often around 150 years and sometimes 300 or more.

The bark is the main ornamental feature. On young trees it is shiny bronze to silvery gold and peels in thin horizontal curls. Old trunks break into scaly red-brown plates. Twigs and stems smell of wintergreen when scratched or snapped. The leaves are simple, alternate and doubly toothed, about 3 to 4 inches long. They are dull dark green above and paler beneath. In autumn they turn a clear yellow.

Male and female catkins grow on the same tree and open in spring, around April to May. The drooping male catkins shift from green to yellowish purple. The female catkins stand upright and stay green. Wind carries the pollen. The fruit is a small upright, hairy cone that ripens in late summer. It holds many tiny winged nutlets.

Yellow birch likes cool summers and evenly moist, rich, acidic loam with good drainage. It grows in full sun or part shade, and full sun gives the best leaf colour. It tolerates wet soil but suffers in heat, drought and compacted ground. It is hardy in USDA zones 3 to 7 and rated H7 in the UK. Mulch helps keep the roots cool and damp. Prune only when dormant, since cuts made while sap runs will bleed.

The tree suits woodland gardens, lawns and naturalised woodland edges. Its wood is hard, heavy and strong, and it makes furniture, flooring, cabinets and veneer. Native peoples used the waterproof bark for canoes, roofing and containers. Seed-eating birds visit the tree. Its leaves feed the caterpillars of moths and the mourning cloak and dreamy duskywing butterflies. Flying squirrels and saw-whet owls nest in its hollows.

Shallow roots make trees in thin, wet soils prone to blowing over. Fungi and bacteria can enter through wounds and frost cracks. Stem cankers and leaf spot also occur. The bronze birch borer is the worst pest, though this birch resists it better than most. Birch skeletonizer, tent caterpillars, gypsy moth caterpillars and sawfly larvae can strip young trees. Aphids are another pest, and deer browse young twigs. The sap is edible and makes syrup or beer, though it holds less sugar than maple sap. In hard times people dried the inner bark and ground it for bread. No hazards are known.