The Elegant Alder Tree

Notes from a Lancashire Countryman.

The common alder tree Alnus glutinosa belongs to the genus Alnus. It is thought that the name derives via 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 the tree created the first man. 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 by way of introduced species. The fungi belongs to the family Phytophthora which in days long ago caused the potato famine in Ireland. However, the reports of this disease seems to have lessened of late.

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

Basic Biology of the Alder Tree

The root of the alder tree contains nodules that are able to transfer nitrogen from the air into the ground which then becomes nutrient rich. The roots may some times be clearly seen in alder carrs during the dry summer months when the water levels drop exposing the roots to be easily observed. The roots tens to have a reddish 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 of plants become stunted and the foliage may well turn a sickly yellow colour long before autumn occurs. There are other plants capable of transferring nitrogen from the air into the ground these include very common plants such as nettles and clover..

The bark is smooth grey at first becoming darker and more scaly with age. The twigs are hairless and of a grey brown colour.

Components of the Alder Tree

Billederafnorden {1800's}
Billederafnorden {1800's}
young alder bark is grey. Photograph by D.A.L.
young alder bark is grey. Photograph by D.A.L.

The trees thrive on wet ground for example by ponds and lakes and in boggy ground in general. They can achieve the height of 20-30metres but are generally smaller than this. They are thought to mature at 60 years of age and their lifespan 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 fact gives rise to the trees species name of glutinosa.

The short stalked rounded leaves 6-12cm long are toothed.

The foliage of alder is small at first but soon expands. Photograph by D.A.L.
The foliage of alder is small at first but soon expands. Photograph by D.A.L.
The foliage is arranged alternate on the twigs. Photograph by D.A.L.
The foliage is arranged alternate on the twigs. Photograph by D.A.L.

The leaves become a dark glossy green colour as the summer progresses. because they are a tree of wet soils the leaves stay 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 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. So many of these male catkins can be produced at this time that from a distance the tree can appear to be in full leaf. They hang down like tasseled ear rings from every twig. The female catkins are smaller being about 2cm long and are more tightly put together than the male catkins. Reddish at first soon becoming green and during the summer months swell into the familiar barrel shaped cone associated with the tree. Indeed these cones are the main way to identify alders for no other native British tree produces cones  , all others that do so are coniferous such as pine and larch.

As the cones mature they become woody in nature and almost black in colour. The seeds contained within the cones are much sought after by siskins and other finches during the winter months when seeds of other trees and plants  are  hard to locate. The seeds have a cork like outer layer that allow them to float in water, thus being carries away from their arboreal mothers to lodge in some muddy bank to germinate.

The caterpillar of the alder moth is often associated with alder foliage they are easily identified by their striking yellow and black segments. The alder kitten moth may also be encountered, they too, are distinctive in their own way being squat and angular with two whip like tails.

Male Catkins

 Photograph courtesy of EnDumEn
Photograph courtesy of EnDumEn

THE WOOD---of alder is readily worked even when green. As the wood is worked it turns to a light orangy colour which found it favour with carpenters and furniture makers. The green wood was employed in the making of whistles and the beautiful sounding pan pipes in days gone by. It was also employed in the country cottage industry providing wood for spinning wheels. Because of its affinity and great resistance to water the wood was utilised in the building 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 larva of a beetle. The larva are commonly referred to as woodworm. Indeed in olden days twigs and pieces of alder wood were placed in the drawers and chests of furniture made of more valuable timber such as oak to attract the wood worms to its protein , thus, leaving the oak alone. The wood was replaced at regular intervals. Alder is also used in the tanning of leather.

The young cones just forming. Photograph by D.A.L.
The young cones just forming. Photograph by D.A.L.

Medicinal uses. alder is considered to have tonic and astringent properties. A decoction of the bark is useful to bathe swellings and inflammations., especially as a gargle for sore throats. In has been stated that heated leaves in a muslin bag is efficient at relieving the symptoms of rheumatism. Culpeper, the 17th century herbalist, recommended that the fresh leaves be placed under the feet of those galled by travelling. They were said to refresh and moisten the feet of people who had been walking all day.

Young Alder trees

A young alder sapling will grow very quickly in its first ten years of life. Photograph by D.A.L.
A young alder sapling will grow very quickly in its first ten years of life. Photograph by D.A.L.

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Comments 9 comments

D.A.L. profile image

D.A.L. 5 years ago from Lancashire north west England Author

Thank you to everyone that has taken the time to comment on THE ELEGANT ALDER TREE, They are appreciated.

D.A.L. profile image

D.A.L. 6 years ago from Lancashire north west England Author

Hi, Yard Thanks for checking in. I know your knowledge of nature is first class also. I like to share the Lancashire wild life with you in return for your wild life being conveyed to me through your hubs. Paul is also very knowledgeable in many subjects he is another writer I admire. Thanks for your comments.

Yard of nature profile image

Yard of nature 6 years ago from Michigan

D.A.L. Just checking in. I'm quite impressed with your work and vast knowledge. Keep spreading the word. Much alder in the woods here. Like Paul said, not much appreciated here, mostly ignored. Interesting about the nitrogen fixing.

D.A.L. profile image

D.A.L. 6 years ago from Lancashire north west England Author

Hi, VAMPGYRL420, Thank you for your visit and for leaving your appreciated comment.

Paul, Alnus rubra, as you say has had some critics, but thankfully people like your good self who realise the benefits of such species, keep it all in prospective. Their nitrogen fixing abilities make the tree beneficial for otherwise barren Infertile soils. Your visit is much appreciated.

paul_gibsons profile image

paul_gibsons 6 years ago from Gibsons, BC, Canada

Alder (and in particular our most common species Red alder -Alnus rubra) is a perennial un-favourite over here. Much maligned due to its habit of growing quickly on any open, disturbed land, shortish lifespan, relative instability and propensity to rot. And yet... it provides early insect food, covers a bare patch quickly, thereby aiding its survival and preventing erosion. But most of all the curious feature of preferring nutrient rich-areas but, if it finds itself in a nutrient poor area it doesn't care that much and does it itself - (it helps)fixing nitrogen, thereby enriching the soil tremendously temporarily, aiding and abetting recolonization by other,less inventive plants. And it is also a good firewood (yes, we do that still here)if dried properly first, giving a good, low-ash heat, and utterly sustainable due to its fast early growth habits..much maligned and much valued at the same time, a bit like a biologist (forced to) working for a developer :). My kind of tree...

VAMPGYRL420 profile image

VAMPGYRL420 6 years ago from The Eastern Shore of Virginia, Maryland and Delaware, U.S.A.

Beautiful Hub, D.A.L. :) The alder is a beautiful tree :)

D.A.L. profile image

D.A.L. 6 years ago from Lancashire north west England Author

hi K thank you for your visit and for taking the time to comment. Always nice to hear from you.

Hi Darski, I know you are a tree lover so I thought you would enjoy this . Thank you for reading.

THANK YOU BOTH-- for pointing out the photograph problem , which I hope has now been rectified. They were coming up on my computer fine. Any way the pictures have now been reloaded.

Darlene Sabella profile image

Darlene Sabella 6 years ago from Hello, my name is Toast and Jam, I live in the forest with my dog named Sam ...

What an excellent hub, also the photo's don't show up as mentioned above...the skin of this tree looks so smooth, maybe that is why is attracts a disease easier then a tree with those layers of rough bark. Wonderful journey on this beautiful trees, thanks for today's walk. Thumbs up and the above...darski

Kaie Arwen profile image

Kaie Arwen 6 years ago

D.A.L.- Elegant is an appropriate word! Heads up, I can't view the pictures in the Hub, but they did show up in the slide show. Might just be me, but I wanted to let you know! K

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