Ulmus davidiana var. japonica

For another plant also known as Japanese elm, see Zelkova serrata.
Ulmus davidiana var. japonica
Japanese elm, Sapporo
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Rosales
Family: Ulmaceae
Genus: Ulmus
Species: U. davidiana
Trinomial name
Ulmus davidiana var. japonica
Rehder
Synonyms
  • Ulmus campestris Komarov
  • Ulmus campestris L. var. japonica Rehder
  • Ulmus campestris var. laevis Fr. Schmidt
  • Ulmus campestris var. vulgaris Shirasawa
  • Ulmus davidiana var. levigata (C. K. Schneid.), Nakai
  • Ulmus davidiana var. japonica f. suberosa Nakai
  • Ulmus japonica (Rehder), Sarg.
  • Ulmus japonica var. levigata C. K. Schneid.
  • Ulmus propinqua Koidz.
  • Ulmus wilsoniana C. K. Schneid.

Ulmus davidiana var. japonica, the Japanese elm, is one of the larger and more graceful Asiatic elms, endemic to much of continental north-east Asia and Japan, where it grows in swamp forest on young alluvial soils, although much of this habitat has now been lost to intensive rice cultivation.[1]

Description

The size and shape of the Japanese elm is extremely variable, ranging from short and bearing a densely branched broad crown similar to the Wych elm[2] to tall, single-stemmed, with narrow crown similar to the English elm[3][4] Augustine Henry described one of the latter outside Iwamigawa, Hokkaido, railway station as being 34 m tall, with a clean stem to a height of approximately 15 m.[5] Japanese elm is distinguished by the fawn colour of shoots at the end of their first season, the shoots often being roughened by minute terbercles or 'warts'.[6][7][8] The young shoots often bear corky wings, similar to those of the European field elm U. minor, to which it is closely related. The leaves are generally obovate, < 11 cm long, and with a coarse upper surface. Like many of the European field elms, var. japonica retains its green foliage well into the autumn, before a late display of deep yellow. Bean noted that the variety from western China, formerly known as U. wilsoniana, has 16 to 22 pairs of leaf-veins, while the eastern type tree has not more than 16.[9] The perfect, apetalous wind-pollinated flowers emerge in early spring, before the leaves. The samara, <15 mm long, is obovate to orbicular, occasionally hairy over its entire surface but more often glabrous,[4][10] the seed touching the notch, the inner margins of which are ciliate, the stigmas being slightly incurved.[11] Trees grown from seed at Great Fontley in southern England first flowered aged 13 years.[12]

Pests and diseases

Natural populations of Japanese elm have a low to moderate resistance to Dutch elm disease. In trials in the Netherlands, susceptibility to disease was found to be commensurate with rate of growth, the more vigorous specimens exhibiting far more foliar damage after inoculation with the causal fungus.[13] Careful selection in North America has produced a number of cultivars highly resistant to disease (see Hybrids, hybrid cultivars and cultivars below). The tree is resistant to the elm leaf beetle Xanthogaleruca luteola but is moderately susceptible to elm yellows.[14]

Cultivation

Japanese elm has been widely planted in northern Japan as a street tree. It was introduced to North America in 1895 as seed sent from Sapporo to the Arnold Arboretum, Massachusetts, whence two seedlings were donated to Kew Gardens, London, in 1897.[15] The Späth nursery, Berlin, marketed Japanese elm in Europe from 1900,[16] Kew obtaining a third specimen from them in that year.[17] Specimens were supplied by Späth to the Royal Botanic Garden Edinburgh in 1903 as U. campestris japonica and may survive in Edinburgh, as it was the practice of the Garden to distribute trees about the city.[18] The Arnold Arboretum specimens grew rapidly, and first flowered aged 12 years. A form from western China, for many years distinguished as U. wilsoniana Schneider, was introduced to the Arnold Arboretum in 1910. Unlike many Asiatic species, Japanese elm is tolerant of a mild, maritime climate with heavy winter rainfall and was consequently considered of potential use in the Dutch elm breeding programme led by H. M. Heybroek at the Dorschkamp Research Institute at Wageningen.[13] In 1977, Heybroek collected the tree in Japan, with the result that there is now a small forest of Japanese elm in southern Flevoland, the largest plantation of the species beyond its native land.[19]

Specimens planted at the Sir Harold Hillier Gardens in Hampshire, England, in 1977 have grown very well on heavy clay in an open location, where they support colonies of the White-letter Hairstreak Satyrium w-album. In trials elsewhere in Hampshire conducted by Butterfly Conservation, the tree also proved tolerant of dry soils on chalk and soils waterlogged in winter, although growth has been comparatively slow.[12] The species is not known to sucker from roots.[4]

Notable trees

Japanese elm features prominently as a campus elm in Hokkaido University, Sapporo, and in the University Botanical Gardens.

In the UK, the TROBI Champion grows at the Sir Harold Hillier Gardens, Romsey, measuring 13 m high by 42 cm d.b.h. in 2003. A possibly larger specimen grows on the Sussex University at Falmer, Brighton, but may be the cultivar 'Jacan'.[21] The oldest specimen in Edinburgh has a bole-girth 3.5 m (2016).[22] Four mature specimens of Japanese elm (the largest with a bole-girth 2.9 m) stand on Leith Links (2013), near the former Leith Academy buildings.[23]

Hybrids, cultivars, and hybrid cultivars

Japanese elm was assessed in Canada as a substitute for native elms which had succumbed to Dutch elm disease. A number of particularly hardy cultivars were released there in the 1980s; three cultivars were also raised in the United States : 'Discovery', 'JFS-Bieberich' = Emerald Sunshine (formerly treated under U. propinqua Koidz.), 'Freedom', 'Jacan', 'Mitsui Centennial', 'Prospector' (formerly treated under Wilson's elm U. wilsoniana C.K. Schneid.), 'Reseda', 'Thomson', Validation[25] However, most of the Canadian clones have now been withdrawn from commerce owing to the Canadian government's restrictions on the movement of elm within the country, adopted to prevent the spread of Dutch elm disease.

The Japanese elm was widely used in the USA in hybridization experiments at the Morton Arboretum and University of Wisconsin,[26][27] resulting in the release of the following cultivars: 'Cathedral', 'Morton' (Accolade), 'Morton Glossy' (Triumph), 'Morton Plainsman' (Vanguard), 'Morton Red Tip' (Danada Charm), 'Morton Stalwart' (Commendation), 'New Horizon', 'Patriot', 'Rebona', 'Repura', 'Revera', and 'Sapporo Autumn Gold'.

The species has also been crossed with Dutch hybrids by the Istituto per la Protezione delle Piante (IPP) in Florence, Italy. Two clones, 'FL 610' and 'FL 626' are currently (2015) under evaluation in England by Butterfly Conservation.[12]

Accessions

North America
Europe

Nurseries

North America
Europe

References

  1. ↑ Makita, H., Miyagi, T., Miura, O., and Kikuchi, T. (1979). A study of an alder forest and an elm forest with special reference to their geomorphological conditions in a small tributary basin. In: Vegetation und Lansdschaft Japans. Bull: Yokohama Phytosoc. Soc. Japan 16, 1979
  2. ↑ T. H., Everett (1969). "Living trees of the world" (PDF). Thames and Hudson.
  3. ↑ F. K., Makins (1967). "The Identification of Trees & Shrubs". Dent.
  4. 1 2 3 H. M., Heybroek (1981). "Proceedings of the Dutch Elm Disease symposium and workshop, October 5–9, 1981, Winnipeg, Manitoba". The Japanese elm species and their value for the Dutch elm breeding program. pp. 78–90.
  5. ↑ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. 1848–1929. Republished 2014 Cambridge University Press, ISBN 9781108069380
  6. ↑ Elwes and Henry (1913), p.1923
  7. ↑ Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London
  8. ↑ Krüssman, Gerd, Manual of Cultivated Broad-Leaved Trees & Shrubs (1984 vol. 3)
  9. ↑ Bean, W. J., 1988
  10. ↑ Fu, L., Xin, Y. & Whittemore, A. (2002). Ulmaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 5 (Ulmaceae through Basellaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA
  11. ↑ Bean (1988), Krüssman (1983)
  12. 1 2 3 Brookes, A. H. (2015). Great Fontley Elm Trial, 2015 Report. Butterfly Conservation, Hants & IoW Branch, England.
  13. 1 2 Heybroek, H. M. (1982). Resistant elms for Europe, in Burdekin, D. A. (Ed.) (1982). Research on Dutch elm disease in Europe. Forestry Commission Bulletin No. 60. HMSO, London
  14. ↑ Mittempergher, L. & Santini, A. (2004). The History of Elm Breeding. Invest. Agrar.: Sist Recur For. 2004 13 (1), 161-177.
  15. ↑ W. J., Bean (1981). "Trees and shrubs hardy in Great Britain, 7th edition". Murray, London.
  16. ↑ Späth Catalogue No.106, p.124 (1900-1901)
  17. ↑ Elwes and Henry (1913), p.1924
  18. ↑ RBGE Cultivated Herbarium Accessions Book: Oct. 1958 notes by Ronald Melville on specimen C2698
  19. ↑ Heybroek, H. M., Goudzwaard, L, Kaljee, H. (2009). Iep of olm, karakterboom van de Lage Landen (:Elm, a tree with character of the Low Countries). KNNV, Uitgeverij. ISBN 9789050112819. Photograph of Japanese elm in the Netherlands
  20. ↑ Labelled 'Forest Elms' by photographer (663highland) on Hokkaido University page
  21. ↑ Johnson, O. (2011). Champion Trees of Britain & Ireland, p. 168. Kew Publishing, Kew, London. ISBN 9781842464526.
  22. ↑ Tree labelled Japanese elm by 'Friends of the Meadows and Bruntsfield Links', in Coronation Walk, The Meadows, Edinburgh: fombl.org.uk
  23. ↑ Japanese elm by former Leith Academy building, Leith Links, Edinburgh (2013): sundialproperties.co.uk (photo 3)
  24. ↑ Kim, M., & Lee, S. (1989). Korean J. Pl. Taxon. 19(1) (1989)
  25. ↑ Burdekin, D. A. & Rushforth, K. D. (revised by Webber, J. F., 1996). Elms resistant to Dutch elm disease. Arboricultural Research Note 2/96. Arboricultural Advisory & Information Service, Alice Holt Lodge, Farnham, England.
  26. ↑ Santamour, J., Frank, S. & Bentz, S. (1995). Updated checklist of elm (Ulmus) cultivars for use in North America. Journal of Arboriculture, 21:3 (May 1995), 121-131. International Society of Arboriculture, Champaign, Illinois, USA
  27. ↑ Smalley, E. B. & Guries, R. P. (1993). Breeding Elms for Resistance to Dutch Elm Disease. Annual Review of Phytopathology Vol. 31 : 325-354. Palo Alto, California
  28. ↑ "List of plants in the {elm} collection". Brighton & Hove City Council. Retrieved 23 September 2016.
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