Elms are deciduous and semi-deciduous trees comprising the flowering plant genus Ulmus. The English Elm was a very common sight in the UK, especially Wales, before the 70’s. It is instantly recognisable by the leaves, which have bristly hairs on the upper surface. Despite potential confusion in their names, Wych elm is actually a more genuine native to this country than the English elm.
L: English Elm (Ulmus procera) R: Wych Elm (Ulmus glabra). Illustrations by Zelimir Borzan, University of Zagreb, Bugwood.org
Invaluable to wildlife, with birds feeding on its seeds and moths on its leaves, the elm was also home to caterpillars of the white letter hairstreak butterfly. Unsurprisingly, this species has declined dramatically since Dutch elm disease took hold. Elm is a favourite with warblers and other insect eating birds.
The leaves of the Wych Elm have toothed edges. Hairs cover the strong ribs on the under surface. And are thought to protect the under surface from dust. When grown in city parks, the leaves of these trees often looked grey as the hairs collected soot from the atmosphere.
Wych Elm seeds by Norbert Frank, University of West Hungary, Bugwood.org
Seeds of the Wych Elm are “winged” so they float through the air. The tree produces seeds after about the 30th year of its life!
The wood is the toughest of European woods and is considered to bear the driving of bolts and nails better than any other. It was used for naves of wheels, shells for tackle-blocks, and common turnery.
It is very durable under water, and was frequently used for keels of ships, for boat building, and for many structures exposed to wet, or when great strength is required. Traditional narrow boats have an elm bottom, made up of 3″ by 7′ planks. Many English towns had elm water mains, including Bristol, Reading, Exeter, Southampton, Hull and Liverpool, before metal was used.
In Celtic mythology, too, elm trees were associated with the Underworld. They had a special affinity with elves who guarded the burial mounds, their dead and the associated passage into the Underworld. This fiction ties in nicely with fact-Elm wood was used to make coffins.
A fungal disease that has devastated populations of elms arrived in the UK in the 1960s. It is called ‘Dutch’ elm disease. The fungus was first described by Dutch scientists, although it is believed to be of Asian origin. It is a type of disease that causes vascular wilt, meaning it blocks the trees water transport system, causing the branches to wilt and die. The fungus is spread from tree to tree by elm bark beetles. These beetles have distinct feeding preferences for certain species of elm. Their favourite in the UK is English elm, and their least preferred is Wych elm.
It has killed an estimated 60 million elm trees in the United Kingdom. It is thought that as few as 100 mature English elm trees survive across England, although young elms still spring up sporadically and can sometimes be seen lining hedgerows before surrendering to this devastating infection. There is no effective cure available, but early sanitation felling, or removal of infected trees and branches, can slow the spread of the disease. This has been effective in helping to retaining good populations of mature elms in some places in Britain, especially in Brighton.
Fungicides, tree vaccines and chemical and biological controls have been or are being developed. However, these treatments have limitations, such as expense, difficulty of application, and the need for them to be repeated, sometimes every year. Their use is therefore likely to be limited to individual trees, or small groups of trees, of high cultural, heritage, landscape or amenity value. Some work is being done in the UK and in continental Europe to identify and breed elms trees which show resistance to, or tolerance of, the fungus, including tolerant hybrid cultivars.
The Duchy of Cornwall is one producer of disease-resistant elms. They are potted up in 5 litre pots and sold at a cost of £25.00. Wouldn’t it be great if we could raise funds to buy some of these elms and put back what Dutch Elm Disease has taken from us?
Watch this space……!