Alnus incana

The grey alder is primarily a tree of northern Europe. In central and southern Europe it grows in the mountains, mainly in the regions of the Alps and Carpathians. It attains a height of only 15 to 20 metres and has smooth grey bark even in old age, its life span being a maximum of 60 to 100 years. The flowers appear in spring about fourteen days before those of the black poplar, the cones and seeds maturing in late September. The seed is light brown with a broad, encircling wing. The grey alder has a shallow root system, and is marked not only by vigorous production of stump suckers, but also by root suckers, especially in the northern parts of its range.

The grey alder is a light-demanding, fast-growing tree that is very tolerant and grows well on poorer soils. In central Europe, it is a colonist of alluvial land alongside mountain brooks and streams, occurring at elevations up to 1500 metres. However, it does not require moist soil, and is a colonist of screes and shallow stony slopes. It is sometimes used for afforestation on non-fertile soils which it enriches by means of its nitrogen-fixing nodules. The wood resembles that of the common alder, but is somewhat paler and of little value.