Black alder (Alnus glutinosa)

  • Drzewa Trees
  • Liściaste Deciduous
  • Liście pojedyńcze Single leaves
  • Ustawione na pędzie skrętolegle Alternating on the stem

Birch family (Betulaceae)


Tree to 30(35) m in height and girth 80(125) cm. Lives 180 years or more. Trunk visible to apex of tree. Bark almost black. Leaves 10(14) cm long, initially sticky, truncate or retuse at the apex, often double-toothed, with matte undersides bearing tufts of hairs. Monoecious, wind-pollinated. Female flowers in small, stalked ”mini-cones”. Woody inflorescences persist on trees; releasing male nutlets in Nov.-Dec., spread by wind and water. Flowers Feb. (Mar.)-Apr., before leaves develop.

Most often grows by water, in riparian and alder forests or carr. A pioneer species, i.a. thanks to symbiotic Frankia alni bacteria that fix nitrogen gas from the air in root nodules.


Descriptions devised by the team at the Independent Department of Forest Botany, Warsaw University of Life Sciences, i.e. L. Witkowska-Żuk, K. Marciszewska, W. Ciurzycki, A. Obidziński and P. Zaniewski