WYCH ELM

The 'Wych Elm ''Ulmus glabra''' Huds., or 'Scots Elm', is a large deciduous tree native to Europe, Asia Minor, and the Caucasus. Essentially a montane species, the tree occurs as far north as latitude 67°N at Beiarn in Norway. In the British Isles, it was by far the most common elm in the north and west of the region. Closely related species such as Bergmann's Elm ''U. bergmanniana'' and Manchurian Elm ''U. laciniata'', native to north-east Asia, were once sometimes included in ''Ulmus glabra''. Another close relative is the Himalayan Elm ''U. wallichiana''.
The tree sometimes reaches heights of 40 m, typically with a broad crown supported by a short bole less than 2 meters in diameter. It is notable for its very tough, supple young shoots. The leaves are deciduous, alternate, simple ovate or obovate with a lop-sided base, 6-17 cm long and 3-12 cm broad; the upper surface is rough. Leaves on vigorous shoots are sometimes three-lobed near the apex. The flowers appear before the leaves in early spring, produced in clusters of 10-20 together; they are 4 mm across on 1cm long stems and, being wind-pollinated, have no petals. The fruit is a winged samara 20 mm long and 15 mm broad, with a single round 6 mm seed, maturing in late spring.

Contents

Subspecies

Dutch Elm Disease

Cultivars

Hybrids and hybrid cultivars

Natural hybrids

Hybrid cultivars

Arboreta etc specimens

North America

Europe

Nurseries

North America

Europe

Australasia

Seed suppliers

Etymology

References

External links

Subspecies

Some botanists divide the species into two subspecies:

★ ''Ulmus glabra'' subsp. ''glabra''. In the south of the species' range. Leaves broad; trees often with a short, forked trunk and a low, broad crown.

★ ''Ulmus glabra'' subsp. ''montana'' (Stokes) Lindqvist. In the north of the species' range (northern Britain, Scandinavia). Leaves narrower; trees commonly with a long single trunk and a tall, narrow crown.
However, there is much overlap between populations in these characters and the distinction may be owing to environmental influence, rather than genetic variation; the subspecies are not accepted by ''Flora Europaea''.

Dutch Elm Disease

The species is highly susceptible to Dutch elm disease once infected. However, it is less favoured as a host by the elm bark beetles that spread the disease. Research in Spain (Martín-Benito et al., 2005) has indicated that it is the presence of a triterpene, alnulin, that renders the tree bark less attractive to the beetle than the Field Elm ''Ulmus minor''. As Wych Elm does not sucker from the roots, and any seedlings often consumed by uncontrolled deer populations, regeneration is very restricted, limited to sprouts from the stumps of young trees. The resultant decline has been extreme and the Wych Elm is now uncommon over much of its former range.
In 1998, over 700 healthy, mature trees were discovered on the upper slopes of Mount Šimonka in Slovakia, but it is now believed they had survived courtesy of their isolation from disease-carrying beetles rather than any innate resistance; 50 clones of these trees were presented to HRH The Prince of Wales for planting at his Highgrove estate, and at Clapham, Yorkshire [1]. Indeed, DNA analysis by Cemagref in France has determined that genetic diversity within the species is very limited, making the chances of a resistant tree evolving rather remote.
Nevertheless, the spread of Dutch elm disease to Scotland has revealed a number of Wych elm apparently surviving there unscathed, prompting the Royal Botanic Garden Edinburgh to clone the trees and inoculate them with the fungus to determine any innate resistance.

Cultivars

Circa 43 cultivars have been raised although many, at least 30, are now probably lost to cultivation as a consequence of Dutch elm disease and/or other factors:

★ Albo-Variegata, Atropurpurea, Australis, Camperdownii (Camperdown Elm), Cebennensis (Cevennes Elm), Cornuta, Corylifolia, Corylifolia Purpurea, Crispa, Crispa Aurea, Dovaei, Escaillard, Exoniensis (Exeter Elm), Fastigiata macrophylla, Fastigiata stricta, Fastigiata variegata, Firma, Flava, Gittisham, Holgeri, Horizontalis (Weeping Elm), Insularis, Latifolia Aurea, Latifolia Aureo-Variegata, Latifolia Nigricans, Luteo Variegata, Lutescens (Golden Wych Elm), Macrophylla, Maculata, Minor, Monstrosa, Nana (Dwarf Wych Elm), Nigra (Black Irish Elm), Oblongata, Pendula Macrophylla, Pendula Variegata, Purpurea, Ramulosa, Rubra, Rugosa, Spectabilis, Tiliaefolia, Tomentosa

Hybrids and hybrid cultivars

Wych Elm has naturally hybridized with ''U. minor'' across much of Europe, their ranges widely overlapping. The hybrid is loosely known as 'Dutch Elm' ''Ulmus × hollandica''; several cultivars of which (notably Vegeta, the Chichester Elm or Huntingdon Elm) have a moderate resistance to Dutch elm disease. The tree has also featured strongly in artificial hybridization experiments in Europe, notably at Wageningen in the Netherlands, and a number of hybrid cultivars have been commercially released since 1960. The earlier trees were raised in response to the initial Dutch elm disease pandemic that afflicted Europe after the First World War, and were to prove vulnerable to the much more virulent strain of the disease that arrived in the late 1960s. However, further research eventually produced several trees immune to disease that were released after 1989.

Natural hybrids

★ ''Ulmus × elegantissima'', ''Ulmus × hollandica''.

Hybrid cultivars

★ Alba, Angustifolia, Arno, Belgica (Belgian Elm), Cinerea, Clusius, Columella, Commelin, Dampieri, Dauvessei, Daveyi (Davey Elm), Den Haag, Dodoens, Dumont, Eleganto-Variegata, Etrusca, Fjerrestad, Fulva, Gaujardii, Groeneveld, Haarlemensis, Hillieri, Homestead, Jacqueline Hillier, Lobel, Major (Dutch Elm), Macrophylla Aurea, Microphylla, Modiolina, Muscaviensis, Nanguen (LUTECE™), Pioneer, Plinio, Regal, San Zanobi, Serpentina, Smithii (Downton Elm), Stavast, Superba, Tricolor, Urban, Vegeta (Huntingdon Elm) / (Chichester Elm), Virens (Kidbrook Elm), Viscosa, Warnoux (VADA™), Wredei (Golden Elm), Ypreau.

Arboreta etc specimens

North America

★ Arnold Arboretum, acc. no. 391-2001, wild collected in Georgia.

★ Bartlett Tree Experts, acc. nos. 1505, 5103, origin undisclosed.

★ Morton Arboretum, acc. nos. 591-54, 255-81, and by its synonym ''U. sukaczevii'' Acc. nos. 949-73, 181-76

Europe

Too numerous to list.

Nurseries

North America

None known.

Europe

Widely available. In the UK, nurseries stocking this tree can be found by using the plantfinder function of the Royal Horticultural Society's website. [2] This tree is also stocked by many local nurseries and by the British Trust for Conservation Volunteers. [3]

Australasia

★ Established Trees Transplanters Pty. Ltd., Wandin, Victoria, Australia, [4]. No details given.

Seed suppliers

★ B and T World Seeds [5], Paguignan, 34210 Aigues-Vives, France

★ Nicky's Nursery Ltd [6], Broadstairs, Kent, UK

Etymology

The word ''wych'' has its origins in Middle English ''wiche'', from the Old English ''wice'', meaning pliant or supple, and which also gives us ''wicker'' and ''weak''. Owing to its former abundance in Scotland, it was occasionally known as the 'Scotch (sic) Elm'; the name Loch Lomond a corruption of the Gaelic ''Lac Leaman'', or 'Lake of the Elms'.

References

★ Flora Europaea: ''Ulmus glabra''

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

★ Brasier, C. M. (1996). New horizons in Dutch elm disease control. Pages 20-28 in: ''Report on Forest Research'', 1996. Forestry Commission. HMSO, London, UK.[7]

★ Elwes, H. J. & Henry, A. (1913). ''The Trees of Great Britain & Ireland''. Vol. VII. pp 1848-1929. Private publication, Edinburgh. [8]

★ Forestry Commission. ''Dutch elm disease in Britain'', UK. [9]

★ Green, P. S. (1964). Registration of cultivar names in Ulmus. ''Arnoldia''. Vol. 24. Arnold Arboretum, Harvard University. [10]

★ Heybroek, H. (1983). The Dutch elm breeding program. In Sticklen & Sherald (Eds). ''Dutch elm disease research'' (Ch. 3). Springer Verlag, New York.

★ 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). [11]

★ Richens, R. H. (1983). ''Elm''. Cambridge University Press.

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

External links

★ http://northernontarioflora.ca/chklst.cfm?speciesid=1005114 Synonymy list.