Ulmus davidiana var. japonica

Ulmus davidiana var. japonica
Japanese Elm, Sapporo
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
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.

Contents

Description

The size and shape of trees of this variety are variable, ranging from short trees bearing densely branched broad crowns to tall, single-stemmed trees with narrow crowns.[1] 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.[2] 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. 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.[1][3]

Ecology

In its natural habitat, this elm variety is most commonly found growing in swamp forest on young alluvial soils, although much of this habitat has now been lost to intensive rice cultivation.[4]

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.[5] 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 [6] but is moderately susceptible to Elm Yellows.[6]

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 seedlings were donated to Kew Gardens, London, two years later.[7][8] The Arnold Arboretum specimens grew rapidly, and first flowered aged 12 years. 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.[5] 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.[9]

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.[10]

The species is not known to sucker from roots.[1]

Hybrids, cultivars, and hybrid cultivars

The tree 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 USA[7]: Discovery, 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, and Thomson.[12] 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,[13][14] 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. Three clones are currently (2008) under evaluation in Italy, and England (by Butterfly Conservation): FL 601, FL 610 and FL 626.

Accessions

North America
Europe

Nurseries

North America
Europe

References

  1. ^ a b c Heybroek, H. M. (1981). The Japanese elm species and their value for the Dutch elm breeding program. Proceedings of the Dutch Elm Disease symposium and workshop. October 5–9, 1981, Winnipeg, Manitoba. pp 78–90
  2. ^ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848–1929. Private publication. [1]
  3. ^ 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 [2]
  4. ^ 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
  5. ^ a b 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
  6. ^ Mittempergher, L. & Santini, A. (2004). The History of Elm Breeding. Invest. Agrar.: Sist Recur For. 2004 13 (1), 161-177.
  7. ^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain. 7th edition. Murray, London.
  8. ^ Japanese elm in 'Coronation Walk' in The Meadows, Edinburgh [3] [4]
  9. ^ 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 9709050112819. Photograph of Japanese elm in Holland [5]
  10. ^ Brookes, A. H. (2006). An evaluation of disease-resistant hybrid and exotic elms as larval host plants for the White-letter Hairstreak butterfly, Satyrium w-album. Part 1. Butterfly Conservation, Lulworth, England.
  11. ^ Kim, M., & Lee, S. (1989). Korean J. Pl. Taxon. 19(1) (1989)
  12. ^ 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.
  13. ^ 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
  14. ^ 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

External links