Ulmus davidiana var. japonica explained

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]

Classification

Some authorities do not consider japonica to be a variety of Ulmus davidiana, The Illustrated Flora of the Primorsky Territory, Russian Far East (2019), for example, maintaining U. japonica as a species.^{[2] [3]}

Description

The size and shape of the Japanese elm is extremely variable,^[4] ranging from short and bearing a densely branched broad crown similar to the Wych elm^[5] to tall, single-stemmed, with narrow crown similar to the English elm.^{[6] [7]} 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.^[8] Takenoshin Nakai distinguished a local cork-barked form, f. suberosa (Flora of Japan, 1965),^[9] while Morton Arboretum, Illinois, distinguishes a cork-barked form from China, U. propinqua var. suberosa.^{[10] [11]} A smooth-leaved form, f. kijimae, was originally named U. kijimae.^[9] 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'.^{[12] [13] [14] [15]} 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. ^[16] Like many of the European field elms, var. japonica retains its green foliage well into the autumn, before a late display of deep yellow. Schneider (1907) and Bean noted that the variety from western China, formerly known as U. wilsoniana,^[17] has 16 to 22 pairs of leaf-veins,^{[18] [19]} while the eastern type tree has not more than 16.^{[20] [21]} 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,^[22] the seed touching the notch, the inner margins of which are ciliate, the stigmas being slightly incurved.^{[23] [24]} Trees grown from seed at Great Fontley in southern England first flowered aged 13 years.^[25] The species does not sucker from roots.^[7]

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. 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 ^[26] but is moderately susceptible to elm yellows.^[27]

Cultivation

Japanese elm has been widely planted in northern Japan as a street tree. It was introduced to Arnold Arboretum, Massachusetts, in 1895 as seed sent from Sapporo by Professor Kingo Miyabe,^[28] whence two seedlings were donated to Kew Gardens, London, in 1897.^[29] The Späth nursery, Berlin, marketed Japanese elm in Europe from 1900,^[30] Kew obtaining a third specimen from them in that year.^[31] Specimens were supplied by Späth to the Royal Botanic Garden Edinburgh in 1903 as U. campestris japonica^[32] and may survive in Edinburgh, as it was the practice of the Garden to distribute trees about the city.^[33] A specimen of U. campestris japonica obtained from Späth stood in the Ryston Hall arboretum, Norfolk,^[34] in the early 20th century.^[35] 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.^{[36] [37]} 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.^[38] 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.^[39]

The tree was briefly propagated and marketed in the UK by the Hillier & Sons nursery, Winchester, Hampshire from 1971 to 1977.^{[40] [41]} Specimens planted at the Sir Harold Hillier Gardens 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 and leaves are late to flush, rarely before mid-May.^[25]

Leaves from the tree were eaten during the Great Chinese Famine, but found to cause facial swelling.^[42]

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'.^[43] The oldest putative specimen in Edinburgh, possibly one of those supplied as U. campestris japonica by Späth in 1903,^[33] had a bole-girth of about 3.5 m (felled 2018).^{[44] [45] [46]}

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 https://web.archive.org/web/20030413074605/http://fletcher.ces.state.nc.us/programs/nursery/metria/metria11/warren/elm.htm: 'Discovery', 'JFS-Bieberich' = (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^[47] 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

• Ulmus × mesocarpa, a natural hybrid of U. davidiana var. japonica and Ulmus macrocarpa was discovered in South Korea in the 1980s.^[48]

The hybrid Ulmus davidiana var. japonica × U. minor was raised at the Arnold Arboretum before 1924.^[49]

The Japanese elm was widely used in the US in hybridization experiments at the Morton Arboretum and University of Wisconsin,^{[50] [51]} resulting in the release of the following cultivars: 'Cathedral', 'Morton' = , 'Morton Glossy' = , 'Morton Plainsman' = , 'Morton Red Tip' = , 'Morton Stalwart' = , '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.^[25]

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 http://www.bbg.org/cgi/bgbase/search.cgi, 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 https://web.archive.org/web/20071025005915/http://www.dawesarb.org/collectionsgardens/plant-search.asp, 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

• Batsford Arboretum, Moreton-in-Marsh, UK. Acc. no. 1997/139/G05 Japan, planted 1999; south of the Japanese Deer statues
• Brighton & Hove City Council, UK. NCCPG Elm Collection.^[52]
• Grange Farm Arboretum, Lincolnshire, UK. Listed as Ulmus japonica; acc. no. 514
• Great Fontley, Fareham, UK, Butterfly Conservation Elm Trials plantation, planted 2002, grown from seed collected from the Great Elm, Hokkaido University, Sapporo, Japan.
• Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18128,29,30,31.
• Linnaean Gardens of Uppsala, Sweden, (as U. japonica). Acc. no. 1998-1284, obtained from the Russian Federation, and 2001-1659, wild collected in South Korea.http://rbg-web2.rbge.org.uk/multisite/multisite3.php
• Royal Botanic Garden Benmore, UK. Listed as U. davidiana var. japonica, acc. no. 19031053.^{[53] [54]}
• Royal Botanic Gardens, Kew, UK. Acc. nos. 1995-581, 1995-1305
• Royal Horticultural Society Garden Rosemoor, Great Torrington, Devon; planted 1988^[55]
• Royal Horticultural Society Gardens, Wisley, UK. Listed as U. japonica, no details available.
• Sir Harold Hillier Gardens, UK. Listed as U. japonica, acc. nos. 1977.5234, 1977.5972, 1977.6373, 1982.4019.
• Tallinn Botanic Garden, Estonia. http://www.tba.ee/index.php?lang=eng. Listed as U. japonica, no accession details available.
• Thenford House arboretum, Oxfordshire, UK, no details available.
• Wijdemeren City Council, Netherlands. Elm Arboretum, Brilhoek, Nederhorst den Berg, 2 planted in 2019 as U. propinqua.

Nurseries

North America

• Patmore Nursery http://patmorenursery.com, Brandon, Manitoba, Canada
• Sun Valley Garden Centre http://www.qscaping.com/NetPS-Engine.asp?CCID=20000011&amp;page=results&amp;Keyword=ulmus&amp;Category=&amp;Type=&amp;Spread=Any&amp;SpreadDim=feet&amp;Growth=&amp;Hardiness=7&amp;Height=Any&amp;HeightDim=feet&amp;Canopy=&amp;Application=&amp;Texture=&amp;Wildlife=&amp;Form=&amp;Density=&amp;FlowerColor=&amp;FlowerColorJS=&amp;FoliageColor=&amp;FoliageColorJS=&amp;FallColor=&amp;FallColorJS=&amp;FruitPeriod=&amp;BarkColor=&amp;BarkColorJS=&amp;FlowerPeriod=&amp;Variegation=&amp;VariegationJS=&amp;FruitColor=&amp;FruitColorJS=&amp;Edible=&amp;BarkTexture=&amp;SunShade=&amp;Moisture=&amp;Pollution=&amp;SoilType=&amp;pH=&amp;Submit=Search, Eden Prairie, Minnesota, US

Europe

• Arboretum Waasland https://web.archive.org/web/20120219064133/http://www.arboretum-waasland.be/English.htm, Nieuwkerken-Waas, Belgium

External links

• USDA Plant Guide: Ulmus davidiana
• Trees and shrubs: illustrations of new or little known ligneous plants, prepared chiefly from material at the Arnold Arboreum of Harvard University, vol.2, ed. C. S. Sargent (Boston & NY, 1913), p.1, U. japonica Sarg. description and illustrations
• efloras.org U. davidiana var. japonica fruit and leaves illustrations (figures 1 to 9)
• efloras.org U. davidiana var. japonica description
• Photographs labelled U. japonica var. suberosa on Plant Photo Bank of China, ppbc.iplant

Notes and 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. Kozhevnikov, Andrey E.; Kozhevnikova Zoya V.; Kwak, Myounghai; Lee, Byoung Yoon (2019), Illustrated Flora of the Primorsky Territory (Russian Far East), National Institute of Biological Resources, Incheon, South Korea
3. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:837143-1 Ulmus japonica (Rehder) Sarg., Plants of the World Online
4. https://archive.org/details/mobot31753003014922/page/259/mode/2up U. japonica Sarg. in Charles Sprague Sargent, ed., Plantae Wilsonianae: an enumeration of the woody plants collected in western China for the Arnold Arboretum of Harvard University during the years 1907, 1908, and 1910 by E. H. Wilson, Vol.3, p.258-261 (Cambridge, Mass., 1916)
5. Web site: T. H.. Everett. 1969. Living trees of the world. Thames and Hudson.
6. Book: F. K., Makins. 1967. The Identification of Trees & Shrubs. Dent. 500545778.
7. Heybroek . Hans M.. Proceedings of the Dutch Elm Disease Symposium and Workshop, October 5–9, Winnipeg, Manitoba. The Japanese elm species and their value for the Dutch elm breeding program. 78–90. 1981.
8. Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. 1848–1929. Republished 2014 Cambridge University Press,
9. https://archive.org/details/floraofjapaninen00oiji/page/380/mode/2up Ohwi, Jisaburo (1905-1977); eds. Meyer, Frederick G., and Walker, Egbert H., Flora of Japan (in English) (Washington, D.C., 1965), p.381
10. http://www.cirrusimage.com/tree_corkbark_elm/ U. propinqua var. suberosa, Morton Arboretum; cirrusimage.com
11. http://ppbc.iplant.cn/sp/294660 Photographs labelled U. japonica var. suberosa on Plant Photo Bank of China, ppbc.iplant
12. Elwes and Henry (1913), p.1923
13. Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London
14. Krüssman, Gerd, Manual of Cultivated Broad-Leaved Trees & Shrubs (1984 vol. 3)
15. https://inaturalist.ca/observations/22320856 Photograph of fawn-coloured japonica shoot with tubercles or warts; inaturalist.ca
16. Hishiyama, C. (Ed.). (2018). A picture book of (Japanese) trees,  p.79. (in Japanese). Seibidoshuppan, Japan.
17. https://archive.org/details/mobot31753003014922/page/237/mode/2up U. wilsoniana Schneider in Charles Sprague Sargent, ed., Plantae Wilsonianae: an enumeration of the woody plants collected in western China for the Arnold Arboretum of Harvard University during the years 1907, 1908, and 1910 by E. H. Wilson, Vol.3, p.238-240 and p.256-257 (Cambridge, Mass., 1916)
18. https://archive.org/details/mobot31753002689096/page/903/mode/2up U. wilsoniana leaf and fruit illustrations in Schneider, Camillo Karl, Illustriertes Handbuch der Laubholzkunde (Jena, 1907), p.903-904
19. Web site: Herbarium catalogue. Ulmus wilsoniana var. wilsoniana. Royal Botanic Gardens, Kew. 17 October 2016. From Chanyang, W. China (Wilson specimen, 1909); Web site: Herbarium catalogue. Ulmus wilsoniana var. psilophylla. Royal Botanic Gardens, Kew. 17 October 2016. From Hupeh, C. China (Wilson specimen, 1907); Web site: Herbarium catalogue. Ulmus wilsoniana var. subhirsuta. Royal Botanic Gardens, Kew. 17 October 2016. From Szechuan, C. China (Schneider specimen, 1914)
20. https://archive.org/details/mobot31753002689096/page/901/mode/2up U. wilsoniana description in Schneider, Camillo Karl, Illustriertes Handbuch der Laubholzkunde (Jena, 1907), p.902
21. Bean, W. J., 1988
22. 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 http://flora.huh.harvard.edu/china/PDF/PDF05/Ulmus.pdf
23. Bean (1988), Krüssman (1983)
24. Sheet labelled U. davidiana Planch. var. japonica (Rehd.), Hokkaido specimen (new leaves and samarae), 1978
25. Brookes, A. H. (2020). Great Fontley Elm Trial, 2020 Report. Butterfly Conservation, Lulworth, England.
26. Web site: Elm Leaf Beetle Survey. 17 July 2017. https://web.archive.org/web/20110719132152/http://www.sunshinenursery.com/survey.htm. 2011-07-19.
27. Mittempergher. L. Santini. A. Investigacion Agraria: Sistemas y Recursos Forestales. The history of elm breeding. 13. 1. 161–177. 2004.
28. Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII., p.1924 Republished 2004 Cambridge University Press
29. Book: W. J., Bean. 1981. Trees and shrubs hardy in Great Britain, 7th edition. Murray, London. 117278583X.
30. Späth Catalogue No.106, p.124 (1900-1901)
31. Elwes and Henry (1913), p.1924
32. Sheet described as U. campestris japonica, RBGE specimen from Späth nursery, 1903
33. RBGE Cultivated Herbarium Accessions Book: Oct. 1958 notes by Ronald Melville on specimen C2698
34. http://www.rystonhall.co.uk/ rystonhall.co.uk/
35. Book: Ryston Hall Arboretum catalogue . c. 1920 . 13–14.
36. http://www.cirrusimage.com/tree_Japanese_Elm.htm U. japonica × U. wilsoniana, Morton Arboretum, cirrusimage.com
37. http://vplants.org/portal/collections/individual/index.php?occid=22110317 U. japonica × U. wilsoniana, Morton Arboretum, acc. no. 495-64, vplants.org
38. D.A.. Burdekin. Forestry Commission Bulletin (Research on Dutch Elm Disease in Europe). 60. Heybroek. Hans M. . HMSO. London. 1983. Resistant elms for Europe. 108–113.
39. 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. . Photograph of Japanese elm in the Netherlands http://www.florapictures.com/photodetail.php?dir=2&amp;photocount=2&amp;plants=ULJAPONI&amp;photoid=1002679800
40. Hillier & Sons (1977). Catalogue of Trees & Shrubs. Hillier, Ampfield, UK.
41. Hillier & Sons Sales inventory 1962 to 1977 (unpublished).
42. 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.
43. Johnson, O. (2011). Champion Trees of Britain & Ireland,  p.168. Kew Publishing, Kew, London. .
44. Tree labelled Japanese elm by 'Friends of the Meadows and Bruntsfield Links', in Coronation Walk, The Meadows, Edinburgh: fombl.org.uk http://www.fombl.org.uk/tr_Japanese%20elm_1.html http://www.fombl.org.uk/tr_Japanese_elm_2.html
45. https://commons.wikimedia.org/wiki/File:Edin-Meadows_09A.jpg Putative Japanese elm, Coronation Walk, The Meadows, Edinburgh, 1989
46. https://commons.wikimedia.org/wiki/File:Edin-Meadows_09B.jpg Bark of putative Japanese elm, Coronation Walk, The Meadows, Edinburgh, 1989
47. Burdekin. D.A.. Rushforth. K.D.. Revised by J.F. Webber. Elms resistant to Dutch elm disease. Arboriculture Research Note. November 1996. 2/96. 1–9. 26 October 2017. Arboricultural Advisory & Information Service. Alice Holt Lodge, Farnham. 1362-5128.
48. Kim, M., & Lee, S. (1989). Korean J. Pl. Taxon. 19(1) (1989)
49. http://quercus.mortonarb.org/search.php?plantName=Ulmus&collectionCombo=&accessnbr= The Morton Arboretum Living Collection, Ulmus list, quercus.mortonarb.org
50. 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
51. 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
52. Web site: List of plants in the collection. Brighton & Hove City Council. 23 September 2016.
53. https://data.rbge.org.uk/search/livingcollection/?cfg=accessions.cfg&acc_num=19031053 Royal Botanic Garden Edinburgh, Catalogue of the Living Collections, data.rbge.org.uk; Ulmus daviana var. japonica
54. https://www.treesandshrubsonline.org/articles/ulmus/ulmus-japonica/ Photograph of RBG Benmore's U. japonica (2017); Internation Dendrology Society, Trees and Shrubs online, U. japonica; treesandshrubsonline.org
55. https://www.treesandshrubsonline.org/articles/ulmus/ulmus-japonica/ Photograph of RHS Rosemoor's U. japonica (2017); Internation Dendrology Society, Trees and Shrubs online, U. japonica; treesandshrubsonline.org