Summary

Overview
There are somewhere in the region of 30 to 35 species in this genus. They belong to the same family as birch (Betulaceae).
The common English name stems from the old English alor; which means root. The roots of the alder tree can often become exposed a river banks.
Alder the trees can be found throughout the UK, Europe, West Asia, and North Africa.
By far the most common in the UK is the common alder all other species are not native to the UK. Someone grown ornamentally and some grow in the wild in varying distributions.
The wood is relatively soft and porous and although it is not very durable when dry it can be repeatedly dried and soaked. With these properties in mind some historic uses include pumps, troughs, small boats, strengthening of river banks and punts. The wood contains a lot of tannins so has been used in dying and ink's.
Modern uses include guitar necks, charcoal, and it is used in turnery. With regards to bushcraft he can be used to make whistles.
Alder grows very fast and contains large numbers of nitrogen nodules in its roots meaning it can grow in poor soil conditions.

Bushcraft
Very useful as widespread and has a lot of uses as the wood can be manipulated when wet. It can be used to make whistles and is believed to have many medicinal uses.

Gallery and Identification

Features common to majority of species:
Size - Species variation - 29m to 5m (Alder (Alnus glutinosa) to Green Alder (Alnus viridis)
Bark - brown, smoother in younger trees, can be fissured in to square plates.
Leaves - leaves are generally ovate; common alder is more rounded at that tip where as most other species have appointed tip. They all have a prominent midrib with between 5 to 8 pairs of veins radiating out to the edge of the leaf; these are hairy on the underside of the leaves. In general the leaves are toothed, however this is not always obvious on common alder.
Reproductive Parts - male catkins contains seeds and are small and woody; these great in bunches of two or three. Female catkins are cone like; around 1.5 cm in size.
Distribution - found throughout the majority of the UK; less so in the Highlands of Scotland. Also found throughout most of Europe, West Asia, and North Africa.
Surroundings - usually found in wet habitats including river banks.
Misc - Aldus are relatively small trees and can be multi stemmed.

Resources

Building matterial

Skills

Whistles

Food

Medicinal uses