Wednesday Weed – Alder

Alder ( Alnus glutinosa) catkins and cones, Kings Cross London

Dear Readers, last week I was in Kings Cross, scouting about for a blogpost on the landscaping that has been done around the old gasholders and the new Coal Drops Yard, when I spotted this magnificent alder on the opposite side of the canal. It was absolutely dripping with catkins and tiny cones, and it reminded me how much I have always liked this native tree. I remember watching the blue and great tits feeding on the cones of an alder in Culpeper Garden in Islington: it was the first time that I’d noticed how the two species portioned out the tree, with the blue tits seeming to stick to the more delicate twigs and the great tits going for the cones on the more robust branches. It might not be the most elegant tree, nor the most august, but as it is a pioneer that grows in boggy ground which most other trees wouldn’t endure, it will always have a place in my heart.

Photo One By No machine-readable author provided. MPF assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=430484

Alder foliage (Photo One)

The buds and young leaves of alder are sticky, and the bark exudes a thick resin, hence the Latin species name ‘glutinosa’. The tree is a member of the birch family (Betulaceae), and it is found across Europe, Central Asia and North Africa. It has been introduced to North America, New Zealand and Australia but because it can thrive in waterlogged and nutrient-poor soils, it is not usually seen as a major problem. The main reason for alder’s resilience is  its symbiotic relationship with a fungus, Frankia alnii, which forms nodules on the plant’s roots and fixes nitrogen from the air in a form that the plant can use, in return for the carbon produced by the tree. This relationship improves the fertility of the soil, making it available to other plants.

Photo Two by By Cwmhiraeth - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=21965251

Alder ‘nodules’ caused by symbiotic fungi Frankia alnii (Photo Two)

However, the seedlings of alder cannot survive overshadowing and so, as the wood that the alder and its fungal ‘friend’ have helped to create becomes more extensive, the alder itself is limited to the forest edges, or to the places which are too wet for other trees to grow. This kind of wet woodland is known as a ‘carr’ (which comes from the Old Norse ‘kvarr’, meaning ‘swamp’).

Photo Three By Bernd Schade - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2138464

Alder carr in Germany (Photo Three)

As you might expect from a tree that already has a healthy relationship with one fungus, there are several other species that are also only associated with alders. One is Russula alnetorum, with its magenta cap and pure white underside.

Photo Four By This image was created by user Irene Andersson (irenea) at Mushroom Observer, a source for mycological images.You can contact this user here. - This image is Image Number 197907 at Mushroom Observer, a source for mycological images., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18254339

Russula sp (Photo Four)

Another is the Alder Roll-Rim, which to my untutored eye has a decidedly chanterelle-ish look about it. This is why you should never send me out foraging for fungi.

Photo Five by By Irene Andersson - This image is Image Number 25465 at Mushroom Observer, a source for mycological images., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15986154

Alder Roll-Rim (Paxillus filamentosus) (Photo Five)

There is even a fungus, catkin cup (Ciboria amentacea), that grows only on the fallen catkins of alder and willow. Don’t they look like the most exquisite miniature wine glasses? Truly, the world is full of wonders.

Photo Six by By Andreas Kunze - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14896380

Catkin cup (Ciboria amentacea) growing on a fallen alder catkin (Photo Six)

But sadly, another fungus has been having a most deleterious effect on the poor old alder – Phytophthora alnii, a recently evolved species, causes a lethal rotting disease, and has been spreading across Europe. It sometimes seems as if all of our trees are under constant threat from pathogens, which makes the need for better plant hygiene in nurseries and when shipping plant products even more important. Although the native alder is not a popular street tree the Italian alder, a close relative, is, especially in the City where the pollution, poor quality of the soil and general disturbance require a robust and resilient tree. Let’s hope that our alders, wild and ‘tame’  are able to survive this latest onslaught.

Photo Six by By User:Gerhard Elsner - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2435628

An alder infected by the Phytophthora alnii fungus (Photo Six)

Alder is extremely useful to wildlife – we have seen how birds eat the cones, but the tree also attracts over 140 species of leaf-eating insect, and the caterpillars of many moths and butterflies feed on the tree, including the delightfully-named alder kitten (Furcula bicuspis) which is a most attractive moth.

Photo Seven by Ben Sale from UK [CC BY (https://creativecommons.org/licenses/by/2.0)]

Alder kitten (Furcula bicuspis) (Photo Seven)

Humans have also used alder extensively. The wood from alder trees is often used in marshy conditions: many of the piles under the city of Venice are made of alder timber, and the Roman engineer Vetruvius mentions that the causeway across the marshes of Ravenna was also made from the tree. The wood is not particularly hard, so it has also been used for coppicing, charcoal making (particularly for use in gunpowder factories)  and for paper. However, alder is also the wood of choice for the bodies of most Fender Stratocaster guitars, both because of its tonal qualities and because the light colour of the wood means that it can take a variety of finishes. If you are thinking of buying an electric guitar and aren’t sure what wood to get it in, there’s an interesting article here, though I suspect that the biological origin of something like a guitar is often overlooked (I certainly hadn’t given it much thought until now).

Photo Eight from https://www.fender.com/articles/tech-talk/ash-vs-alder-whats-the-diff

A Fender Telecaster guitar with alder body (Photo Eight)

Alder was also said to be the wood of choice for woodworm larvae, and so branches of the tree were sometimes brought into houses so that the insects could munch harmlessly away on their favourite food instead of gnawing their way through the weight-bearing beams.

The various parts of alder produce a variety of different dye colours: the catkins produce a green dye, which has been associated with the ‘Lincoln green’ hue of the clothing of Robin Hood and his Merry Men. The bark contains a high degree of tannin, and can be used to dye clothes brown. The fresh-cut wood can produce a pinkish dye: when the tree is injured the exposed wood quickly turns brownish-red and looks as if it is bleeding, which may be why there is an Irish legend that it is unlucky to pass an alder tree when on a journey.

The photo below shows wool dyed with madder (orange), weld (yellow) and alder (brown).

Photo Nine from https://medieval-colours.co.uk/products/autumn-set-of-yarns-alder-madder-weld

Wool dyed with weld (yellow), madder (orange) and alder (brown) from Medieval Wools (see below for link) (Photo Nine)

Medicinally, the bark has been used in a decoction to treat burns, inflammation and sore throats. It was believed that alder leaves placed into the shoes before a long walk would soothe tired feet (and alder wood was also used to make clogs in the industrial North of England during Victorian times). The bark has also been used as a toothpaste. In the Alps, peasants would warm up bags of alder leaves and use them to relieve the pain of arthritis during the long, cold winter nights.

Although in the UK the alder is often viewed as something of a ‘weed tree’, it featured in one of the most important works of the Dutch Golden Age of landscape painting. ‘The Avenue at Middelharnis’ by Meindert Hobbema was created in 1689, and is thought to be an extremely accurate portrayal of this avenue of alders, which were planted in 1664. This was an unusual departure for Hobbema, who usually painted idealised landscapes made up of several different locations. The man working amongst the saplings on the lower right of the painting is also unusual – there had previously been a sense that these landscapes had just sprung into being, rather than being intensely man-made. Hobbema was largely thought to have stopped painting some twenty years before this work was made: he had a lucrative job as a ‘wine-gauger’, someone who collected the taxes on locally-produced wine. This is a particularly successful late work, described by the American Dutch art specialist Seymour Sleve as ‘the swan song of Holland’s great period of landscape painting which fully deserves its high reputation’. I am not a great fan of landscape painting, but there is something rather enigmatic about this work – it beckons me on, between those rather lanky alders, towards the church.

The Avenue at Middelharnis by Meindert Hobbema (1689) (Public Domain)

And oh, how happy I am to find this poem by Seamus Heaney, with which to end my celebration of the alder. To hear the man himself reading the poem, click here. How deeply he loved the land that he grew up in, and how poignantly it comes through in his work.

PLANTING THE ALDER

For the bark, dulled argent, roundly wrapped
And pigeon-collared.

For the splitter-splatter, guttering
Rain-flirt leaves.

For the snub and clot of the first green cones,
Smelted emerald, chlorophyll.

For the scut and scat of cones in winter,
So rattle-skinned, so fossil-brittle.

For the alder-wood, flame-red when torn
Branch from branch.

But mostly for the swinging locks
Of yellow catkins.

Plant it, plant it,
Streel-head in the rain.

© 2006, Seamus Heaney
From: District and Circle
Publisher: Faber & Faber, London, 2006

 

Photo Credits

Photo One By No machine-readable author provided. MPF assumed (based on copyright claims). – No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=430484

Photo Two by By Cwmhiraeth – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=21965251

Photo Three By Bernd Schade – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2138464

Photo Four By This image was created by user Irene Andersson (irenea) at Mushroom Observer, a source for mycological images.You can contact this user here. – This image is Image Number 197907 at Mushroom Observer, a source for mycological images., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18254339

Photo Five by By Irene Andersson – This image is Image Number 25465 at Mushroom Observer, a source for mycological images., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15986154

Photo Six by By Andreas Kunze – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14896380

Photo Seven by Ben Sale from UK [CC BY (https://creativecommons.org/licenses/by/2.0)]

Photo Eight from https://www.fender.com/articles/tech-talk/ash-vs-alder-whats-the-diff

Photo Nine from https://medieval-colours.co.uk/products/autumn-set-of-yarns-alder-madder-weld

 

 

 

 

10 thoughts on “Wednesday Weed – Alder

  1. tonytomeo

    Native alder grows wild right outside. It is a riparian species. Years ago, it was one of those temporary trees that grew up fast to provide shade in a new landscape while the more desirable trees took their time. By the time they started to die out, the more desirable trees were maturing. That technique is no longer practical because no one wants to cut down trees anymore.

    Reply
  2. Natasha de Chroustchoff

    Lovely post, full of fascination. You might also want to check out the curious ‘alder tongue gall’ Taphrina alni which produce weird distortions of the cones, usually found in late spring or summer on the developing cones.

    Reply
  3. Anne

    As far as is practical, we shouldn’t simply cut down trees anymore. This post has been an incredibly satisfying read and I am delighted to find Seamus Heaney at the end – he is a poet close to my heart in terms of his connection to the land.

    Reply
  4. Sarah Ann Bronkhorst

    Can’t find the Alder Roll-rim in any of my books but all the roll-rims are dubious and/or toxic so I always avoid. Russulas are so elegant, with their coloured caps and crisp, close-packed white gills, but sorting out the edible ones is beyond me.

    Reply
  5. Pingback: Alder Leaf Beetle | The Hospice Gardener

  6. Toffeeapple

    How marvellous, all the information about the Alder and to end with Seamus Heaney – well! You know how much I love his voice.

    Reply

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