Ulmus procera
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.JPG/265px-PP-5-71990_(25).JPG) English Elm, Preston Park, Brighton.
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| Ulmus procera Salisb. |
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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, often exceeding 40 m in height with a trunk up to 2 m d.b.h diameter [1]. The largest specimen ever recorded in England, at Forthampton Court, near Tewkesbury, was 46 m tall [2]. 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 flowers are without petals, and appear in early spring before the leaves . The tree does not produce fertile seed, and propagation is entirely by root suckers [3] [4] [5].
A survey of genetic diversity in Spain, Italy and the UK [6] [3] revealed that the English Elms are genetically identical, clones of a single tree, the Atinian Elm once widely used for training vines. Although there is no record of its introduction to Britain, it probably arrived with the Romans, a hypothesis supported by the discovery of pollen in an excavated Roman vineyard. The introduction of the tree to Spain from Italy is recorded by the Roman agronomist Columella in his treatise De Re Rustica, written circa AD 50; it has also identified it as the elm grown in the vineyards of the Valais, or 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.
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[edit] Dutch elm disease
- For more detailed information on the disease, see Dutch elm disease
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 [4]. It was an ideal subject for such an experiment, as its sterility meant there was no danger of its introgression into the countryside.
[edit] Brighton and the 'cordon sanitaire'
The English Elm population in Britain was decimated by Dutch Elm Disease. Despite this, mature trees can still be found in 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.).
[edit] Other notable trees in the UK
Mature English Elms are now only very rarely found beyond Brighton. Until circa 2006 several large trees survived in the Royal Botanic Garden Edinburgh but these too died when the area succumbed to the northward advance of Dutch elm disease.
[edit] Overseas trees
As a consequence of Empire, some of the most significant remaining stands are to be found overseas, notably in Australia [7] 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 [8]. 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 [9]. In the USA, several fine trees survive in New York City, notably the Hangman's Elm in Washington Square Park [10].
[edit] 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. 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. "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" [2].
[edit] Cultivars
There has been a small number of cultivars raised since the early 19th century [11], three of which have now almost certainly been lost to cultivation:
[edit] Arboreta etc. accessions
[edit] North America
- Longwood Gardens, acc. no. L-2507.
- Morton Arboretum, acc. nos. 211-40, 756-60, 351-70.
[edit] Europe
- Brighton & Hove City Council, NCCPG Elm Collection. UK champion: Preston Park, 15 m high (storm damaged), 201 cm d.b.h. in 2001 [12]. 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.
- The Cuckmere Valley, East Sussex. Around Westdean village, along what is lnown as "The Cathedral Walk"; Litlington, Lullington and Alfriston.
- Grange Farm, Sutton St. James, Spalding, Lincolnshire, UK, acc. no. 518.
- Strona Arboretum [5], University of Life Sciences, Warsaw, Poland.
- University of Copenhagen, Botanic Garden, one specimen, no details available.
- Westonbirt Arboretum [6],Tetbury, Glos., UK, four trees, listed as U. minor var. vulgaris (no planting dates nor acc. nos. available).
[edit] Australasia
- Eastwoodhill Arboretum [7], Gisborne, New Zealand, 12 trees, details not known.
- Waite Arboretum [8], University of Adelaide, Adelaide, Australia
[edit] Nurseries
[edit] North America
- Wild Thyme Farm [9]
[edit] Europe
[edit] Australasia
- Established Tree Planters Pty. Ltd., Wandin, Victoria, Australia. [11]
- Fleming's Nursery [12], Monbulk, Victoria, Australia
[edit] References
- ^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain. Murray, London.
- ^ a b Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848-1929. Private publication. [1]
- ^ Richens, R. H. (1983). Elm. Cambridge University Press
- ^ Stace, C. A. (1997). New Flora of the British Isles. Cambridge University Press.
- ^ White, J. & More, D. (2002). Trees of Britain & Northern Europe. Cassell's, London
- ^ Cogulludo-Agustin, M. A., Agundez, D. & Gil, L. (2000) Identification of native and hybrid elms in Spain using isozyme gene markers; Heredity, August 2000, vol. 85. Nature Publishing Group, London.
- ^ Spencer, R., Hawker, J. and Lumley, P. (1991). Elms in Australia. Australia: Royal Botanic Gardens, Melbourne. ISBN 0724199624
- ^ Fitzgibbon, J. (2006) Royal Parade Elm Replacement. Elmwatch, Vol. 16 No. 1, March 2006.
- ^ Auckland Botanical Society (2003). Journal Vol. 58 (1), June 2003. ISSN 0113-41332
- ^ Barnard, E. S. (2002). New York City Trees. Columbia University Press
- ^ Green, P. S. (1964). Registration of cultivar names in Ulmus. Arnoldia, Vol. 24. Arnold Arboretum, Harvard University. [2]
- ^ Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 9781873580615.
[edit] External links
- http://redwood.mortonarb.org/PageBuilder?cid=2&qid= Morton Arboretum Catalogue 2006
