Alder

Alder, common name for a group of shrubs and trees native to cold and temperate climates. Because the alder's wood resists decay underwater, it is used for bridge pilings. Dye was formerly obtained from the bark of many species. The common alder is a native of Europe. It usually grows to about 15 m (50 ft). Among the varieties used for ornamental planting are the golden alder, with bright golden-yellow leaves, and the cut-leaved alder, with narrow, deeply incised leaves. The grey alder has acute leaves, downy underneath, and grows to a height of about 24 m (80 ft).

Scientific classification: Alders belong to the family Betulaceae. The common alder is classified as Alnus glutinosa and the grey alder as Alnus incana.