Ulmus davidiana var. japonica

Ulmus davidiana var. japonica, the Japanese elm, is one of the larger and more graceful Asiatic elms, endemic to much of continental northeast 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]

For another plant also known as Japanese elm, see Zelkova serrata.

Ulmus davidiana var. japonica
Ulmus davidiana var. japonica, Obihiro, Hokkaido, Japan
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Ulmaceae
Genus: Ulmus
Species:
U. davidiana
Variety:
U. d. var. japonica
Trinomial name
Ulmus davidiana var. japonica
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.

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] The Morton Arboretum, Illinois, distinguishes a cork-barked form from China, U. propinqua var. suberosa.[6] Japanese elm is distinguished by the fawn colour of shoots at the end of their first season, the shoots often being roughened by minute tubercles or 'warts'.[7][8][9] 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, with a petiole about 10mm long. [10] 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.[11] 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][12] the seed touching the notch, the inner margins of which are ciliate, the stigmas being slightly incurved.[13] Trees grown from seed at Great Fontley in southern England first flowered aged 13 years.[14]

  • Japanese elm, showing pendulous habit of lower branchlets. SHHG, Romsey, UK
  • Japanese Elm leaves
  • David Elm (left) and Japanese Elm (right) leaves for comparison
  • Bark of 30-year-old tree

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.[15] 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 [16] but is moderately susceptible to elm yellows.[17]

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.[18] The Späth nursery, Berlin, marketed Japanese elm in Europe from 1900,[19] Kew obtaining a third specimen from them in that year.[20] 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.[21] A specimen of U. campestris japonica obtained from Späth stood in the Ryston Hall arboretum, Norfolk,[22] in the early 20th century.[23] 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. The Morton Arboretum, Illinois, has intermediate forms labelled U. japonica × U. wilsoniana.[24][25] 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.[15] 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.[26]

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.[14] The species does not sucker from roots.[4]

Leaves from the tree were eaten during the Great Chinese Famine, but found to cause facial swelling.[27]

  • Japanese elm, Sapporo
  • Autumn colouring of Japanese Elm, Hokkaido University Botanical Gardens, Sapporo (November 2013)[28]
  • Japanese elms, Hokkaido University Botanical Gardens
  • Old tree in Hokkaido University Botanical Gardens, Sapporo (November 2013)
  • Elms at main gate of the Sapporo Campus of the Hokkaido University

Notable trees

In the UK, the TROBI Champion grows at the Royal Horticultural Society's Rosemoor garden in Devon, measuring 16 m tall in 2017. Another large tree grows at the Sir Harold Hillier Gardens, Romsey, measuring 13 m tall by 42 cm d.b.h. in 2003. A large specimen grows at Sussex University, Falmer, Brighton, but may be the cultivar 'Jacan'.[29] The oldest putative specimen in Edinburgh, possibly one of those supplied as U. campestris japonica by Späth in 1903,[21] had a bole-girth of about 3.5 m (felled 2018).[30][31][32]

Cultivars

Japanese elm was assessed in Canada as a substitute for native elms which had succumbed to Dutch elm disease. Six particularly hardy cultivars were released there in the 1980s; three 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[33] 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.

Hybrids and hybrid cultivars

The Japanese elm was widely used in the US in hybridization experiments at the Morton Arboretum and University of Wisconsin,[35][36] 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' were evaluated in England, by Butterfly Conservation.[14]

Accessions
North America
  • Arnold Arboretum, US. Acc. nos. 4119 (from cult. material), 917-78, wild collected in Korea.
  • Brenton Arboretum, US. Listed as U. wilsoniana; no details available.
  • Brooklyn Botanic Garden , New York, US. Acc. no. 780251 (listed as U. japonica).
  • Chicago Botanic Garden, US. 1 tree in the West Collections Area, listed as U. propinqua var. suberosa.
  • Dawes Arboretum , US. 1 tree, no acc. details available.
  • Holden Arboretum, US. Acc. nos. 80-664 (unrecorded provenance), 97-126, wild collected in Korea.
  • Morton Arboretum, US. Acc. nos. 514-39, 679-62, 680-62, 354-U, 23-2008, 73-2011, also two others under the synonyms of U. propinqua Koidz. or cork bark elm (acc. no. 53-96), and U. propinqua Koidz. var. suberosa, collected from the Nei Mongol Zizhiqu Autonomous Region, China, (acc. no. 52-95).
  • U S National Arboretum, Washington, D.C., US. Acc. no. 68998. Also (listed under synonym U. japonica): 76253, 76254, 76227, and (listed under syn. U. propinqua): 76249, 68985, and (listed under U. propinqua var. suberosa): 76234, 76244, 76241.
Europe

Nurseries
North America
Europe
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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. OCLC 500545778.
  4. Heybroek, Hans M. (1981). "The Japanese elm species and their value for the Dutch elm breeding program" (PDF). Proceedings of the Dutch Elm Disease Symposium and Workshop, October 5–9, Winnipeg, Manitoba: 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. U. propinqua var. suberosa, Morton Arboretum; cirrusimage.com
  7. Elwes and Henry (1913), p.1923
  8. Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London
  9. Krüssman, Gerd, Manual of Cultivated Broad-Leaved Trees & Shrubs (1984 vol. 3)
  10. Hishiyama, C. (Ed.). (2018). A picture book of (Japanese) trees,  p.79. (in Japanese). Seibidoshuppan, Japan. ISBN 9784415310183
  11. Bean, W. J., 1988
  12. 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
  13. Bean (1988), Krüssman (1983)
  14. Brookes, A. H. (2020). Great Fontley Elm Trial, 2020 Report. Butterfly Conservation, Lulworth, England.
  15. Heybroek, Hans M. (1983). Burdekin, D.A. (ed.). "Resistant elms for Europe" (PDF). Forestry Commission Bulletin (Research on Dutch Elm Disease in Europe). London: HMSO (60): 108–113.
  16. "Elm Leaf Beetle Survey". Archived from the original on 2011-07-19. Retrieved 17 July 2017.
  17. Mittempergher, L; Santini, A (2004). "The history of elm breeding" (PDF). Investigacion Agraria: Sistemas y Recursos Forestales. 13 (1): 161–177.
  18. W. J., Bean (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London. ISBN 117278583X.
  19. Späth Catalogue No.106, p.124 (1900-1901)
  20. Elwes and Henry (1913), p.1924
  21. RBGE Cultivated Herbarium Accessions Book: Oct. 1958 notes by Ronald Melville on specimen C2698
  22. rystonhall.co.uk/
  23. Ryston Hall Arboretum catalogue. c. 1920. pp. 13–14.
  24. U. japonica × U. wilsoniana, Morton Arboretum, cirrusimage.com
  25. U. japonica × U. wilsoniana, Morton Arboretum, acc. no. 495-64, vplants.org
  26. 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
  27. Baranov, A .L. (1962). On the economic use of wild plants in N. E. China. Quarterly Journal of the Taiwan Museum, 15 (122), 1962, 107–115.
  28. Labelled 'Forest Elms' by photographer (663highland) on Hokkaido University page
  29. Johnson, O. (2011). Champion Trees of Britain & Ireland,  p.168. Kew Publishing, Kew, London. ISBN 9781842464526.
  30. Tree labelled Japanese elm by 'Friends of the Meadows and Bruntsfield Links', in Coronation Walk, The Meadows, Edinburgh: fombl.org.uk
  31. Putative Japanese elm, Coronation Walk, The Meadows, Edinburgh, 1989
  32. Bark of putative Japanese elm, Coronation Walk, The Meadows, Edinburgh, 1989
  33. Burdekin, D.A.; Rushforth, K.D. (November 1996). Revised by J.F. Webber. "Elms resistant to Dutch elm disease" (PDF). Arboriculture Research Note. Alice Holt Lodge, Farnham: Arboricultural Advisory & Information Service. 2/96: 1–9. ISSN 1362-5128. Retrieved 26 October 2017.
  34. Kim, M., & Lee, S. (1989). Korean J. Pl. Taxon. 19(1) (1989)
  35. 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, US
  36. 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
  37. "List of plants in the {elm} collection". Brighton & Hove City Council. Retrieved 23 September 2016.
  38. Royal Botanic Garden Edinburgh. (2017). List of Living Accessions: Ulmus
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