Very similar in appearance and timber use, there are nevertheless some important differences between Silver birch and Downy birch.
Best situations
The main and very important difference is where these two varieties are best suited to be grown. Downy birch grows further north and west and in wetter soils even boggy heavy clay soils, at high altitudes and more exposed sites and is ideally suited to growing in Scotland. Silver birch grows further south and east and in drier soils. Birch often grows in mixtures with other broadleaf trees, particularly oak in the south and west and pine in the north and east, although pure birch stands are common in the Highlands. Downy birch tolerates shade better than silver birch.
Bark differences
In appearance terms, Betula pendula has a whiter trunk with more dark fissures. The bark of Silver birch is pink-ish white with horizontal grey bands and in older trees the bark becomes white with big black diamond shaped fissures. Downy birch has red-brown bark coming smooth greyish-white with variable horizontal bands grey to brown, often like a cherry tree in appearance.
Tree shape
The crown of Silver birch is narrow, pointed and upswept in young trees, domed at the top with long pendulous branchlets, whereas Downy birch is a more irregular shaped tree, soon losing the pointed top, more spreading and not pendulous.
Foliage differences
The foliage of Silver birch is purple brown shoots, covered with white warts, and the leaves are rounded-triangular tapering to a fine point with teeth. The petriole (where the leaves join onto the stem) is slender with no hairs. Downy birch shoots are greyish red purple, covered in short, soft, shiny white hairs. The leaves are rounded, often nearly circular, with broad rounded teeth and the petiole is densely pubescent.
Eventual height
Silver birch reaches a height of about 30m whereas Downy birch reaches up to 20m.