ULMUS LAEVIS

'''Ulmus laevis''' Pall., the 'European White Elm', yclept 'Fluttering Elm, Spreading Elm', and (USA only) 'Russian Elm' is a large deciduous tree native to Europe, from France northeast to southern Finland, and southeast to Bulgaria and the Crimea; there is also a disjunct population in the Caucasus. Essentially endemic to alluvial forest, it is rarely encountered at elevations above 400 m (Girard, 2007). Most commonly found along rivers such as the Volga and Danube, it is the only elm tolerant of waterlogged ground, its massive shallow root system forming distinctive high buttresses around the base of the trunk.
Like other European elms, it has little innate resistance to Dutch elm disease, but is not favoured by the vector bark beetles, which colonize it only when there are no other elm alternatives available, an uncommon situation in western Europe. Research in Spain (Martín-Benito et al., 2005) has indicated that it is the presence of a triterpene, alnulin, that renders the tree bark unattractive to the beetles. Ergo: the tree's decline in western Europe is chiefly owing to woodland clearance in river valleys, not disease.

Similar in stature to the Wych Elm, it typically reaches a height of over 30m and a trunk diameter of up to 2 m. The leaves are deciduous, alternate, simple ovate with a lop-sided base, < 10 cm long and < 7 cm broad, rough above, and downy underneath. The flowers appear before the leaves in early spring, produced in clusters of 15-30 together; they are 3-4 mm across on 20 mm long stems, have no petals and are wind-pollinated. The fruit is a winged samara 15 mm long and 10 mm broad with a single round 5 mm seed maturing in late spring. The tree is distinguished from other European elms by the long flower stems, and is most closely related to the American Elm ''U. americana'', from which it differs mainly in the irregular crown shape and frequent small sprout stems on the trunk.
The species was never widely introduced to the USA, but is represented at several arboreta; there is also a notable specimen in Portland, Oregon. In the Far East, the tree has been planted in Xinjiang province and elsewhere in Northern China; planting in Tongliao City is known to have been particularly successful. The tree is not known to have been introduced to Australasia.
Examples in the UK are few and far between, but sometimes of great age. Several old trees survive amid diseased native elm near Torpoint in Cornwall [1]; others are found in Edinburgh, London (Peckham and Tooting), Brighton & Hove, and near St. Albans, Hertfordshire. A particularly fine tree stands in the village of Alfriston, East Sussex. However, in recent years, the tree has enjoyed a small renaissance in England. A popular larval host plant of the White-letter Hairstreak ''Satyrium w-album'' butterfly across Europe, the elm is now being planted by ''Butterfly Conservation'' and other groups to restore local populations decimated by the effects of Dutch elm disease on native or archaeophytic elms. The Cheshire Wildlife Trust, for example, is to plant 1,000 White Elms on its reserves [2] in the Vale Royal district of the county.

Contents

Forms

Cultivars

Hybrid cultivars

Arboreta etc. accessions

North America

Europe

Nurseries

North America

Europe

Seed suppliers

References

External links

Forms

In Russia several decorative forms are recognized: f. ''aureovariegata'', f. ''argentovariegata'', f. ''rubra'', and f. ''tiliaefolia''.

Cultivars

Compared with the other European species ''U. glabra'' and ''U. minor'', ''U. laevis'' has received scant horticultural attention, there being only five recorded cultivars, none of which are known to remain in cultivation, with the possible exception of 'Colorans':
Aureo-Variegata, Colorans, Ornata, Punctata, Urticaefolia.

Hybrid cultivars

In common with the American Elm ''U. americana'', ''U. laevis'' does not hybridize naturally, and the few reported instances of artificial hybridization in the 19th century are now regarded with suspicion.

Arboreta etc. accessions

North America

★ Arnold Arboretum, acc. nos. 17910, 637-79, 6951, 753-80.

★ Brenton Arboretum, Dallas Center, Iowa. No details available.

★ Dominion Arboretum, Canada. No details available

★ Longwood Gardens, acc. nos. 1964-0568, 1964-1119.

★ Morton Arboretum acc. nos. 1302-27, 446-48, 492-64, 27-98.

Europe

★ Arboretum de La Petite Loiterie [3], Monthodon, France. No details available

★ Brighton & Hove City Council, UK, NCCPG Elm Collection.

★ Copenhagen University, Botanic Garden. No details available.

★ ELTE Botanic Garden Budapest, acc. nos. 1998-0718, 1998-0719.

★ Great Fontley Farm, Fareham, UK, ''Butterfly Conservation'' Elm Trials plantation, Home Field K2, Platts N10, (planted 2003).

★ Hortus Botanicus Nationalis, Salaspils, Latvia acc. nos. 18136, 18140.

★ Royal Botanic Gardens Kew, UK, acc. nos. 1969-17302, 1973-11712.

★ Royal Botanic Gardens, Wakehurst Place, UK, acc. no. 1973-21048.

★ Royal Horticultural Society Gardens, Wisley, UK. No details available.

★ Sir Harold Hillier Gardens, UK, acc. no. 1981-2446.

★ Thenford House arboretum, Oxfordshire, UK. No details available.

Nurseries

North America

None known

Europe

★ Boomkwekerij Oirschot [4], Oirschot, The Netherlands

★ Crown Nursery [5], Ufford, Suffolk, UK

★ Dulford Nurseries [6], Cullompton, Devon, UK

★ Thornhayes Nursery [7], Cullompton, Devon, UK

★ UmbraFlor [8], Spello, Italy

Seed suppliers

★ Chiltern Seeds, Bortree Stile, Ulverston, Cumbria, LA12 7PB, England [9]

References

★ Bean, W. J. (1981). ''Trees and shrubs hardy in Great Britain'', 7th edition. Murray, London.

★ Brookes, A. H. (2006). ''An evaluation of disease-resistant hybrid and exotic elms as larval host plants for the White-letter Hairstreak Satyrium w-album, Part 1.'' [10]. Butterfly Conservation. Lulworth, UK.

★ Collin, E., Bilger, I., Eriksson, G., & Turok, J. (2000). The conservation of elm genetic resources in Europe. In Dunn, C. P. (Ed.) (2000). ''The elms: breeding, conservation & disease management''. Kluwer Academic Publishers, Boston.

★ Elwes, H. J. & Henry, A. (1913). ''The Trees of Great Britain & Ireland''. Vol. VII. pp 1848-1929. Private publication. [11]

★ Girard, S. (2007). Dossier: L'orme: nouveaux espoirs? ''Forêt entreprise'' No. 175, Juillet 2007, Institut pour le developpement forestier, Paris.

★ Martín-Benito D., Concepción García-Vallejo M., Alberto Pajares J., López D. 2005. Triterpenes in elms in Spain. ''Can. J. For. Res.'' 35: 199–205 (2005).

★ More D. & White, J. (2003). ''The Trees of Britain & Northern Europe'', Cassell's, London.

External links

★ http://www.fao.org/docrep/006/AD110E/AD110E01.htm Flora of the Korqin Sandy Lands, China.

★ http://www.bioversityinternational.org/publications/Pdf/921.pdf Ecology of the European White Elm

★ http://www.wildlifetrust.org.uk/cheshire/news_white_letter_hairstreak.htm The Vale Royal White-letter Hairstreak Project, Cheshire Wildlife Trust, UK