English Elm
From Wikipedia, the free encyclopedia
 |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 English Elms in Fitzroy Gardens, Melbourne.
|
||||||||||||||
|
|
||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
|
|
||||||||||||||
| Ulmus procera Salisb. |
||||||||||||||
|
|
||||||||||||||
|
Ulmus atinia: Walker Ulmus campestris L., Loudon, Planch., Moss Ulmus minor var. vulgaris Richens Ulmus sativa Mill. Ulmus suberosa Smith, Loudon, Lindley Ulmus surculosa Stokes var. latifolia Stokes, Ley |
English Elm Ulmus procera Salisb. is found across most of southern England, in Spain and central Italy. DNA analysis has now identified the tree with the Atinian elm once widely used for training vines in Italy; a survey of genetic diversity of trees in Spain, Italy and the UK [1] revealed that the trees in the UK are clones, genetically identical to a single tree that possibly arrived with the Romans. Its introduction to Spain is recorded by the Roman agronomist Columella in his treatise De Re Rustica, written circa AD 50. Although there are no records of its introduction to England, it is now widely assumed that it too was imported by the Romans, a hypothesis supported by the discovery of pollen in an excavated Roman vineyard.
The English Elm was once one of the largest and fastest-growing deciduous trees in Europe, often exceeding 40 m in height, with a trunk up to 2 m in diameter. 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, with an oblique base and toothed edges. Wind-pollinated, the small, reddish-purple 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.
Contents |
[edit] 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 English hedgerows 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 [2].
[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 Control Area in Sussex. This designated control area extends from the river Adur in the west approximately 30 km eastwards to Pevensey Bay, and inland by up to 10 km. Empowered by the Dutch Elm Disease (Restriction on Movement of Elms) (Amendment) Order 1988 [3], local authorities may order the destruction of any infected trees or timber, although in practice they usually do it themselves, successfully reducing the numbers of elm bark beetle Scolytus spp, the vector of Elm Disease. This 'cordon sanitaire', aided the prevailing south westerly onshore winds and the topographical niche formed by the South Downs, has saved many mature elms. Amongst these are the world's largest surviving English Elms, known as the 'Preston Twins' in Preston Park, both exceeding 600 cm in circumference. Away from the town centre parks, many other elms, notably Ulmus × hollandica Vegeta (the Huntingdon or Chichester Elm) and Ulmus minor subsp. sarniensis (syn. Wheatley Elm) survive as street trees owing to their tolerance of shallow soil and coastal winds. Mature English Elms are now rarely found beyond Brighton's parks, however there are still many mature English Elms in Edinburgh, Scotland; especially around the Meadows and Bruntsfield Links, as yet undiscovered by the beetles.
[edit] Overseas 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. In the USA, several fine trees survive in New York, notably the Hangman's Elm in Washington Square Park.
[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" [Elwes & Henry, 1913].
[edit] Cultivars
There have been as small number of cultivars raised since the early 19 th century: Acutifolia, Argenteo-Variegata, Aspera, Folia Aurea, Louis van Houtte, and Pyramidalis.
[edit] Hybrid cultivars
There are no hybrid cultivars.
[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.
- Copenhagen University, Botanic Garden, one specimen, no details available.
- Royal Botanic Garden Edinburgh, acc. no. not given.
[edit] Nurseries
[edit] North America
- Wild Thyme Farm [4]
[edit] Europe
[edit] Australasia
- Established Tree Planters Pty. Ltd., Wandin, Victoria, Australia. [6]
[edit] References
- Armstrong, J. V. & Sell, P. D. (1996). A revision of the British elms (Ulmus L., Ulmaceae): the historical background. Bot. J. Linn. Soc. 120: 39-50.
- Barnard, E. S. (2002). New York City Trees. Columbia University Press.
- Bean, W. J. (1981). Trees and shrubs hardy in Great Britain. Murray, 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.
- Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848-1929. Private publication. [7]
- 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.
[edit] External links
- http://redwood.mortonarb.org/PageBuilder?cid=2&qid= Morton Arboretum Catalogue 2006
