Alder, common

A native of Britain, but also found throughout the rest of Europe as far as Siberia, alder is a characteristic tree of wet places, marshes and stream-sides.

What other names does it have?

Can also be known as	Fern (old Irish) Aller Aller-Tree Whistle-Wood (northern England) Irish Mahogany
Generic name	Alder
Latin name	Alnus glutinosa
Family name	Birch
Latin family name	Betulaceae

What type of tree is it?

Is it a broadleaf or conifer?	It is a broadleaf
Does it lose its leaves in autumn?	Yes, it is deciduous

Species description:

Average height	18-25m

Leaf

Description	Racquet-shaped and leathery with serrated edges. The tip is never pointed and is often indented.
Shape	Oval
Colour	Dark green
Leaf bud	Generally mauve (but can be duller and grey). The buds are club shaped and stalked.
Leaf stalk	Long stalk
Leaf arrangement	Alternate

Flower, seed, and fruit

Type of flower	Catkin
Flowering season	February to early April
Fruit colour	Brown
Type of seed body	Cone
Seeds dispersed by	Wind Water

Bark and twig

Bark description	Dark brown. Square plated/cracked with the verticals dominating
Twig Description	Brown and notched. Hairless

What other trees are similar?

Can easily be confused with?	Downy alder - the leaves of which are larger, double toothed, and often downy

Where is it usually found?

Is it native or non-native to the British Isles?	Native
Where is its natural range?	Britain and Ireland
Preferred soil type or environmental conditions?	Wet areas such as river sides, wet woods, marshes and bogs. Often planted on land reclamation sites.
What is its British conservation status?	Common

Additional information

Human uses of tree and timber

Alder timber is very resistant to decay under water and was therefore used for water pipes, pumps, troughs, small boats and piles under bridges and houses. In fact, much of Venice is built on alder piles. The two other main uses of alder wood are charcoal and for making clogs. Alder was popular for charcoal as it was particularly favoured in gunpowder. Clogs made from alder wood were light, easy to wear and absorbed shocks well.

Tree lore and folklore

Alder wood is a lure for woodworm, (as the beetles lay their eggs in alder in preference to other wood), so branches were cut and put in cupboards to prevent woodworm in other woods. There are few other folklore assocations. Except, in Ireland it was thought to be unlucky to pass an alder on a journey. Possibly because alder grows in marshy ground!

Alder tree

Alder montage

Alder bark

Illustrations supplied by
Collins

BritishTrees