Alder vs. Birch

Alder and birch are types of deciduous trees that belong to the birch family. There are 30 species of alder and 30 to 60 species of birch. They are native to the northern hemisphere. Both plants can be found in the forests and near the streams and rivers. Alder prefers soil of coarse texture, while birch usually grows on slightly "softer" soil (gravelly and cobbly soil). Alder and birch are cultivated mostly in ornamental purposes and as a source of wood. Here are some characteristics that can facilitate identification of these plants in the wild:

Size

Both birch and alder can grow in the form of bush or small- to medium-sized tree. Alder can reach 16 to 98 feet, while birch can reach 40 to 70 feet in height.

Bark

Young alder trees have grey-green, smooth bark. Mature alder trees have darker bark that is either fissured or flaky. Birch has thin and smooth bark that is nearly black-colored in young trees. Mature birch trees have white, yellow, grey, reddish-brown or black bark, depending on the species, with numerous white lenticels (horizontal pores).

Leaves

Alder has yellow-green, racquet-shaped leaves with indented tips and finely serrated edges. They are alternately arranged on the branches. Birch has oval or elliptical leaves with pointed tips and toothed margins. They are greenish-yellow on the upper side, and light-green on the bottom side. Leaves of birch are arranged in pairs.

Flowers and Fruit

Birch and alder are monoecious plants. They produce individual male and female flowers (called catkins) on the same tree. Adler produces yellow, solitary, drooping male catkins and oval-shaped, green female catkins arranged in clusters of 3 to 8. Male catkins are produced at the beginning of the winter, but they do not release pollen until the spring. After successful pollination, female catkins transform into hard, woody, cone-like fruit which opens its "scales" to release seed. Birch produces drooping male catkins that can be solitary or arranged in clusters. They are yellow-orange in the middle, and dark brown at the tips. Male catkins are produced during the autumn. Female catkins are light yellow or green colored with a tinge of red. They are solitary and oriented either upwards or downwards. Unlike alder, mature female catkins are papery and they disintegrate during the process of seed release.

Part of Human Diet

Catkins of some types of birch tree are rich source of proteins and they can be used in human diet. Birch sap can be consumed unprocessed or used for the manufacture of birch syrup (similar to maple syrup).

Timber

Alder wood is used for the manufacture of guitars, furniture and cabinets. Birch is used for the manufacture of veneer, plywood, furniture, guitars, drums and paper.