Ulmus procera

Ulmus procera Salisb., the English Elm or Atinian Elm was, before the advent of Dutch elm disease, one of the largest and fastest-growing deciduous trees in Europe. A survey of genetic diversity in Spain, Italy and the UK revealed that the English Elms are genetically identical, clones of a single tree, the Atinian Elm once widely used for training vines, and brought to the British Isles by Romans. Thus, the origin of U. procera is widely believed to be Italy, although it is possible the tree hailed from what is now Turkey, where it is still used in the cultivation of raisins.

Description

The tree often exceeded 40 m in height with a trunk < 2 m d.b.h . The largest specimen ever recorded in England, at Forthampton Court, near Tewkesbury, was 46 m tall .

The leaves are dark green, almost orbicular, < 10 cm long, without the pronounced acuminate tip at the apex typical of the genus. Wind-pollinated, the small, reddish-purple hermaphrodite apetalous flowers appear in early spring before the leaves . The tree does not produce fertile seed, and propagation is entirely by root suckers .

Pests and diseases

Owing to its homogeneity, the tree has proven particularly susceptible to Dutch elm disease, but immature trees remain a common feature in the English countryside courtesy of the ability to sucker from roots. After about 20 years, these too become infected by the fungus and killed back to ground level. English Elm was the first elm to be genetically engineered to resist disease, at the University of Abertay Dundee [http://www.guardian.co.uk/print/0,3858,4246134-103690,00.html]. It was an ideal subject for such an experiment, as its sterility meant there was no danger of its introgression into the countryside.

In the USA, U. procera was found to be one of the most preferred elms for feeding by the Japanese Beetle Popillia japonica [http://www.bioone.org/doi/full/10.1603/0022-0493%282001%29094%5B0445%3APOTCEU%5D2.0.CO%3B2].

The leaves of the English Elm in the UK are mined by Stigmella ulmivora.

Cultivation

Although there is no record of its introduction to Britain, the tree probably arrived with the Romans, a hypothesis supported by the discovery of pollen in an excavated Roman vineyard. It is possible the tree was used also as a source of leaf hay. The introduction of the tree to Spain from Italy is recorded by the Roman agronomist Columella; it has also identified it as the elm grown in the vineyards of the Valais, yclept Wallis, canton of Switzerland. More than a thousand years after the departure of the Romans from Britain, the English Elm found far greater popularity, as the preferred tree for planting in the new Hawthorn hedgerows appearing as a consequence of the Enclosure movement, which lasted from 1550 to 1850. In parts of the Severn Valley, the tree occurred at densities of over 1000 per square kilometre, so prolific as to have been known as the 'Worcester Weed'

Notable trees

As a consequence of Empire, some of the most significant remaining stands are to be found overseas, notably in Australia where they line the streets of Melbourne, protected by geography and quarantine from disease. However, many of these trees, now over 100 years old, are succumbing to old age, and are being replaced with new trees raised by material from the older trees budded onto Wych Elm Ulmus glabra rootstock . The tree has been widely planted in New Zealand, and is still commonly found in Auckland where it is regarded at its best as a street tree . In the USA, several fine trees survive in New York City, notably the Hangman's Elm in Washington Square Park .

Brighton and the 'cordon sanitaire'

Although the English Elm population in Britain was decimated by Dutch elm disease, mature trees can still be found along the south coast Dutch Elm Disease Management Area in East Sussex. This 'cordon sanitaire', aided by the prevailing south westerly onshore winds and the topographical niche formed by the South Downs, has saved many mature elms. Amongst these are possibly the world's oldest surviving English Elms, known as the 'Preston Twins' in Preston Park, both with trunks exceeding 600 cm in circumference (2.0 m d.b.h.).

Uses

The English Elm was once valued for many purposes, notably as water pipes from hollowed trunks, owing to its resistance to rot in saturated conditions. The wood has a density of around 560kg per cubic metre. However, it is chiefly remembered today for its aesthetic contribution to the English countryside, where it sometimes occurred in densities of over 1000 per square kilometre. In 1913 Henry Elwes wrote that "Its true value as a landscape tree may be best estimated by looking down from an eminence in almost any part of the valley of the Thames, or of the Severn below Worcester, during the latter half of November, when the bright golden colour of the lines of elms in the hedgerows is one of the most striking scenes that England can produce" .

Cultivars

There has been a small number of cultivars raised since the early 19th century <Ref name=Green>Green, P. S. (1964). Registration of cultivar names in Ulmus. Arnoldia, Vol. 24. Arnold Arboretum, Harvard University. [http://arnoldia.arboretum.harvard.edu/pdf/articles/1605.pdf]</ref>, three of which have now almost certainly been lost to cultivation: Acutifolia, Argenteo-Variegata, Folia Aurea, Louis van Houtte, Pyramidalis.

Accessions

North America

Longwood Gardens. Acc. no. L-2507.
Morton Arboretum. Acc. nos. 211-40, 756-60, 351-70.

Europe

Brighton & Hove City Council, NCCPG Elm Collection. UK champion: Preston Park, 15 m high (storm damaged), 201 cm d.b.h. in 2001 . Brighton & Hove has some 700 trees; the most notable examples are at Preston Park, South Victoria Gardens, Royal Pavilion Gardens, The Level, St. Peter's Church, Holmes Avenue, Preston Road (A23), Elm Square (Patcham) and Hanover Crescent. More can be found in East Sussex along the Cuckmere Valley, Westdean village, along what is known as "The Cathedral Walk"; Litlington, Lullington and Alfriston.
Grange Farm Arboretum, Sutton St. James, Spalding, Lincolnshire, UK. Acc. no. 518.
Strona Arboretum [http://en.wikipedia.org/wiki/Ulmus_lamellosa], University of Life Sciences, Warsaw, Poland. No details available.
University of Copenhagen, Botanic Garden. One specimen, no details available.
Westonbirt Arboretum [http://www.forestry.gov.uk/forestry/infd-62qk8w],Tetbury, Glos., UK. Four trees, listed as U. minor var. vulgaris; no acc. details available.

Australasia

Avenue of Honour, Ballarat, Australia. Details not known.
Eastwoodhill Arboretum [http://www.eastwoodhill.org.nz/gardens--collection/collection.aspx?Type=Collection&L=U], Gisborne, New Zealand. 12 trees, details not known.
Waite Arboretum [http://www.waite.adelaide.edu.au/arboretum/], University of Adelaide, Adelaide, Australia. No details available.

Nurseries

North America

Wild Thyme Farm [http://sonic.net/~wildfarm/ripcrpplant.html]

Europe

Buckingham Nurseries, UK, [http://www.buckingham-nurseries.co.uk/acatalog/index.html]
Elmcroft Tree Nursery, Bradford Lane, Newent, Glos., UK.

Australasia

Established Tree Planters Pty. Ltd., Wandin, Victoria, Australia. [http://establishedtrees.com.au]
Fleming's Nursery [http://www.flemings.com.au/], Monbulk, Victoria, Australia

Translation of "Ulmus procera"

German: Englische Ulme, Dutch: Engelse veldiep.