There are two species of alder in Sweden, common alder, Alnus glutinosa, and grey alder, Alnus incana. The first grows mainly in the south, up to Gästrikland, Dalarna and Värmland. Grey alder is a northern tree and can be found down to Bergslagen.
Common alders bark is smooth and shiny with a greenish tint, and that on older trees is dark brown and coarse. Buds and young leaves are slightly glutinous. Grey alder, young and old trees alike, have smooth bark with a silver grey tone. Trunks can sometimes be very crooked, and the leaves are more pointed compared to common alder. Alder is the only broad-leaf tree that has cones. The leaves do not turn yellow in autumn but stays green until they fall.
Common alder need a lot of light and moisture. It prospers along waters, swamps and beaches and usually grows to about 25 meters height.
Grey alder do not depend on light and moisture as much as common alder; it can even grow on dry, sandy soils. It rarley gets taller than 20 meters.
Common alder is easy to work. The wood is light reddish brown, or orange pink if used green. Its uses include clogs and tool handles, since it is light in weight and do not give splinters. Common alder works well for furniture making since it has small dimensional changes once seasoned. It is very decay resistant under water and therefore suitable for underwater constructions and piles.
Wood from gray alder is lighter in color than common alder, softer, has more knots and smaller dimensions, which is why it is mostly used for crafting small items. It is not as decay resistant as common alder. Most saw mills do not distinguish them but sells both as alder.
Alder can develop big burls at ground level. These give a coral-looking type of wood reminding of masur birch. It is hard, durable and a popular material for veneer. It is marketed as alder root. Craftsmen use it for cups, handles and for veneer on fine furniture.
Did you know that:
The bark is reddish and is used for tanning and dyeing.
DuriDuring years of famine the bark was mixed with flour for baking and leaves were used as forage.
In folk medicine both bark and leaves were used as bandages for burns and open wounds.