The Black Alder (Alnus glutinosa)

It is generally a small tree or shrub. They are magnificent colonizers and are often used to reclaim poor, wet, unhealthy soils; in fact, through their roots, they fix nitrogen in the soil, performing nitrogen fixation.

The wood is very water-resistant: Venice is entirely built on foundations of piles, mostly made of alder, taken from the forests of the Venetian and Friulian Prealps and from those of Cadore, Carnia, and Istria.