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Our native alder is a medium sized tree with a narrow crown and short, spreading branches. It grows extensively in damp places alongside streams, rivers, ponds and lakes as well as marshy areas.

There are a number at Upton Country Park where the water is, of course saline, so it seems to be tolerant of salt. In some boggy areas it grows in great perfusion and forms the habitat commonly called alder carr. Alder is rarely planted as it has little forestry value although wood turners quite like it because the wood is both strong yet easily worked. 

The tree has both sexes of flowers on it. There are the male catkins that resemble hazel catkins but are longer. The female flowers develop a little later and are smaller, cylindrical and are purplish brown in colour. The flowers are wind pollinated.

Fertile female flowers develop in to small cones and they will often stay on the tree all winter, long after the seeds have dropped. The seeds themselves are distributed generally by floating on the water until they reach land. These cones, which are quite unique for a deciduous tree, are quite often the defining feature in winter. 

The alder bears on its roots little nodules that contain a live bacterium which enable it to make soluble nitrogen salts out of the inert nitrogen of the air. Consequently, the soil on which alder grows is remarkably fertile. 



The records for this species have been organised into reports, charts, maps and photos. Click a pic below to see the detail:

Sites List Distribution Map Some Charts Some Photographs Original Tweets Relatives Guidance Notes
Common Name Alder
Scientific Name Alnus glutinosa
Family Birch family - Betulaceae
Status Locally frequent
Interest Level
Species Family Deciduous Trees
Flower Colour Group Purple
  • 02 - February
  • 03 - March
Preferred Environment
Look for Large purple catkins tinged with green when fully open
Additional Identification Notes
Similar Species

This species is often found in these habitats:

Habitat(s) Relationship
W4: Wet Woodland Indicator
FF: Fen and carr Associated