Alder
Irish Name - Fearnóg
Ulster-Scots - Allertree
Family - Betulaceae
Characteristics
- Alder usually grows to a height of 15m but occasionally reaches 30m.
- When young, these trees have strong single trunks and are conical in outline, but become broadheaded with age.
- Young trees grow quickly when in suitable conditions and are capable of putting on as much as one metre's growth a year at this stage.
- Roots sometimes grow near the base of the stems and help support the trees in unstable ground. Such new growth is particularly common on coppiced plants.
- Alder trees put more nitrogen in the soil than they use, so they build up soil fertility.
- An established alder has a deep-probing tap root, about 1.5m long, which enables the tree to survive falling water levels during drought.
Season
- Alder produces yellow catkins early in February and March.
Preferred Environment
- Alder seed is generally distributed by wind and water. The seedlings survive waterlogging, but require high levels of light, humidity and oxygen, which restrict natural establishment to river banks and mud. This means that alder is found frequently along streamsides and in marshland where it can become dominant in areas which are not permanently flooded.
- It thrives best in moist loam with a high humus content. It is, however, tolerant of most soils, except chalk, and is able to withstand prolonged root submergence. For this reason alder is often successful on reclaimed land.
Wildlife Associations
- There are 90 associated insect species identified with alder.
Uses
- When dry, alder wood is water-resistant, and does not split when nailed. It is used for broom and tool handles.
- Alder is a hard but easily carved yellow timber that is still used occasionally as the traditional material for the soles of clogs or wooden shoes.