Alder tree.Alnus glutinosa.


MEDICINAL HISTORY --YES {covered in text}


 Get to know the Alder Tree--

The common alder tree,Alnus glutinosa belongs to the genus Alnus. {see LATIN NAMES EXPLAINED}  The name is thought to derive from the Anglo-Saxon alor, or aler. In Europe it is often known as the black alder while in the U.K. it is simply the common alder. North American species include the Mountain alder Alnus tenuifolia, White alder A.rhombifolia and the Red alder A.rubra.

In Scandinavian mythology the alder is said to be the tree from which woman was created.Conversely in Ireland the mythology conveys to us that it is the tree to first create man.


 courtesy of Maksim CC BY-SA 3.0 license.Tagalder8139.jpg


Photograph above alder tree in winter showing new catkins and the old woody cones.

The alder tree came under attack from a fungal infection that destroyed many trees across Europe. It was first discovered in the south of England during 1993. The fungi was thought to have been imported with introduced species of alder. The fungi belongs to the family Phytophthora which in days long ago caused the potato famine in Ireland.However, the reports of this disease seem to have lessened of late.

Alders have often been used as wind breaks.They are also employed by foresters to protect young, more vulnerable and valuable timber saplings until they become established. Thus they are a good nurse crop.

Description of the alder.

The root of the alder tree contains nodules that are capable of transferring nitrogen from the air into the ground, which then becomes nutrient rich.The roots may some times be clearly seen in alder carrs during during dry summers when water levels drop, exposing the roots that can easily be observed. The roots tend to be of an orange colour making them almost unmistakeable. At first glance one can be forgiven for thinking that the roots are diseased, however,the bacteria is beneficial to the tree.

Nitrogen helps the growth of stems, leaves, flowers and the seeds. Without nitrogen growth would become stunted,the foliage may well turn a sickly yellow before falling well before autumn.There are other plants capable of taking nitrogen from the air and transferring it in to the ground,these include common plants such as the nettle and clovers.

Photographs top-alder foliage,on the left new young leaf just opened. on the right a leaf that has been opened a couple of wings. BELOW-The trunk of a young alder tree by a lake.

The bark of the alder is smooth grey at first becoming darker with age and more scaly. The twigs are hairless and of a grey brown colour. The trees thrive on wet ground for example by ponds and lakes and in boggy ground in general.They can achieve the height of 20-30m but are generally smaller than this. They are thought to mature at about 60 years of age and their life span is around 150 years. 

The young twigs and leaf buds and the young leaves when they first unfurl have a sticky resinous substance which protects them from insect damage.This gives rise to the trees species name of glutinosa. {see link LATIN NAMES EXPLAINED} .

The short stalked rounded leaves are 6-12cm long and are toothed. They are very small at first but soon expands. They soon become a dark glossy green colour as the summer progresses Because the trees grow in wet or damp conditions the foliage remains green well into the autumn and remain green when other trees are adorned in their autumn colours.

The flowers of the alder are wind pollinated catkins.Male and female catkins grow on the same tree. The male catkins that appear in late winter and early spring are cylindrical but linear about 10cm long and of a reddish yellow colour when ripe. So many of these  male catkins  can be produced by the tree  that from a distance they can appear to be in full leaf.They cascade down from every twig. The female catkins are smaller and much more tightly packed than the loose male flowers. They are reddish at first but quickly turn green swelling in the summer months to the barrel shaped cones associated with the tree. Indeed, these cones are a key identification factor for the alder is the only British native broad-leaved tree to produce cones. All others that do so belong to the coniferous family such as pines and the larch tree. As the cones mature they become woody in nature and almost brown or even black in colour. The seeds contained within are much sought after by finches, in particular the siskin, during the winter months when seeds of other trees and plants have all but gone. The seeds have an outer coating which is cork like and allow the seeds to float on water, thus being carried away from their arboreal mothers to lodge in some muddy bank to germinate.

The caterpillar of the alder moth is often associated with the leaves. They are easily identified by their striking yellow and black segments. The alder kitten moth is also associated with the tree and are distinctive in their own right, being squat and angular with whip like tails.

THE WOOD---of alder is readily worked even when green. As the wood is worked it turns an orangey colour which found favour with carpenters and furniture makers alike. The green wood was employed in the making of whistles and the beautiful sounding pans pipes in archaic times. It was also employed to produce spinning wheels.Because of its affinity with water and its remarkable endurance of water the wood was utilised in the making of bridge supports and canal lock gates.

It is not, however, used  in the construction of houses. Because of its high protein level it attracts the larvae of a beetle. The larvae are commonly referred to as "wood worm".  Indeed,in olden days twigs and pieces of alder were placed in the drawers and chests of furniture made of much more valuable timber  such as oak, so as to attract the larvae to its protein,thus, leaving the more expensive wood alone. The wood was replaced at regular intervals. Alder is also used in the process of tanning leather.

Medicinal uses.

Alder is considered to have tonic and astringent properties. Decoctions were produced using the bark which was said to be efficient at treating swellings and inflammations, especially as a gargle for sore throats. In has been stated that heated leaves in a muslin bag is good at relieving the symptom of rheumatism. Culpeper the 17th century herbalist, recommended that the fresh leaves be placed under the feet of those galled by traveling. they were said to refresh and moisten the feet of people who had been walking all day.

Medicinal uses are for historical interest only. Alder is not recommended for home made preparations.

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