European White Elm

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. Moreover, a small number of trees found in Spain is now considered a relict population rather than an introduction by man, and possibly the origin of the European population [4] ^[1]. Essentially endemic to alluvial forest, it is rarely encountered at elevations above 400 m ^[2]. Most commonly found along rivers such as the Volga and Danube, it is the only elm tolerant of waterlogged ground, its extensive 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 ^[3], an uncommon situation in western Europe. Research in Spain ^[4] has indicated that it is the presence of a triterpene, alnulin, that renders the tree bark unattractive to the beetles. Therefore: 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 with a trunk of up to 2 m d.b.h. The two largest known trees in Europe are at Gülitz [5] in Germany (3.1 m d.b.h.), and Komorów in Poland (2.96 m d.b.h.).

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; they are 3-4 mm across on 20 mm long stems and, being wind-pollinated, have no petals. 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 ^[5] ^[6] ^[7].

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 also known to have been introduced to Australia ^[8].

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 [6], including the UK Champion at Ferry Farm, Harewood (27 m high, 179 cm d.b.h.); others can be 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 ^[9]. The Cheshire Wildlife Trust, for example, is planting 1,000 White Elms on its reserves [7] in the Vale Royal district of the county.

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

Nurseries

Seed suppliers

References

^ Fuentes-Utrilla, P., Squirrell, J., Hollingsworth, P. M. & Gil, L. (2006). Ulmus laevis (Pallas) in the Iberian Peninsula. An introduced or relict tree species? New data from cpDNA analysis. Genetics Society, Ecological Genetics Group conference, University of Wales Aberystwyth 2006.
^ Girard, S. (2007). Dossier: L'orme: nouveaux espoirs? Forêt entreprise No. 175, Juillet 2007, Institut pour le developpement forestier, Paris.
^ 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.
^ 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). [1]
^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London.
^ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848-1929. Private publication. [2]
^ White, J. & More D. (2003). The Trees of Britain & Northern Europe, Cassell's, London.
^ Spencer, R., Hawker, J. and Lumley, P. (1991). Elms in Australia, Royal Botanic Gardens, Melbourne, Australia. ISBN 0724199624
^ 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. [3]. Butterfly Conservation. Lulworth, UK.

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