Ulmus davidiana

Ulmus davidiana
David Elm, Great Fontley, England.
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Rosales
Family: Ulmaceae
Genus: Ulmus
Species: U. davidiana
Binomial name
Ulmus davidiana
Planch.
Synonyms
  • Ulmus davidiana var. mandshurica Skvortsov
  • Ulmus davidiana var. pubescens Skvortsov

Ulmus davidiana Planch., the David elm, is a small deciduous tree widely distributed across China, Mongolia, Korea, Siberia, and Japan, where it is found in wetlands along streams at elevations of 2000 m to 2300 m (6,500 to 7,500 ft).[1] The tree was first described in 1873 from the hills north of Beijing, China.[2]

Classification

Two varieties of Ulmus davidiana are recognized: var. davidiana L.K.Fu, occurring only in China, and var. japonica Rehder, the more widely ranging Japanese Elm.

Description

Ulmus davidiana is considered to have a remarkable resemblance to the American elm (U. americana) in all but ultimate size.[3] The tree grows to a maximum height of 15 m (50 ft), with a relatively slender trunk < 0.3 m (1 ft) d.b.h. supporting a dense canopy casting a heavy shade. Its bark is longitudinally fissured. The leaves are obovate to obovate-elliptic < 10 cm (4 in) × < 5 cm (2 in), with a rough upper surface, often dark red on emergence. The perfect, wind-pollinated apetalous flowers are produced on second-year shoots in March, followed by obovate samaras < 19 mm (3/4 in) long × < 14 mm (1/2 in) wide.

Pests and diseases

Evaluated with other Chinese elms at the Morton Arboretum in Illinois, the tree was found to have a good resistance to Dutch elm disease (DED) [4] . In the Butterfly Conservation trials in the UK, trees grown from seed obtained in Liaoning, China, by the Morton Arboretum were damaged by DED when only 6 years old and < 4 m (31 ft) high, but survived.[5] The species is reputed to have a good resistance to Elm Leaf Beetle Xanthogaleruca luteola, Elm Yellows (elm phloem necrosis) and leafminers in the USA.[4]

Cultivation

Ulmus davidiana is only rarely cultivated in the West, being unsuited to all but very sheltered, humid conditions, and is intolerant of ponding. In trials conducted by Butterfly Conservation at Great Fontley Farm, Fareham, England, specimens often grew too rapidly in the comparatively benign conditions, the narrow stem unable to bear the weight of the burgeoning crown, leaving the tree arching to the ground [5] ("Pruning can help the plant result in a more structurally stable branching pattern" [6]). The same trees commenced flowering when aged nine years, in mid-March.

There are no known cultivars of this taxon, nor is it known to be in commerce beyond the USA.

Recent testing at The Ohio State University

The David Elm has shown some promise as a result of recent testing at the Ohio State University (OSU) in Ohio.[6][7] At OSU, the plants were cultivated in copper-lined pots and planted in a wide lawn under a powerline and in small home lawns. The tree's performance has been mixed, but shows potential. Some specimens did extremely well, while others struggled. The tree seems to perform well on disturbed sites, in calcifereous (alkaline) soils, and also seems to have a better tolerance for wet soil than the literature has indicated. A number of strong saplings were cultivated that show promise. Some saplings underwent judicious pruning early on to maximize structural stability of the plant, and blue-colored tree shelters were used on some plants until the stem reached a diameter of between 25 mm to 37 mm.

Additional observation shows that at least 50% of emerging leaves on the trees survived a hard freeze that lasted 5 days during April 2007. Leaves were approximately 70% emerged when temperatures fell to −6°C (21°F). Temperatures fell below freezing for 5 days (April 4–8, 2007).

Notable trees

The UK TROBI Champion is a relatively young tree at White House Farm, Ivy Hatch, Kent, measuring 5 m high by 17 cm d.b.h. in 2009. [8]

Etymology

The tree is named for Father Armand David, the French missionary and naturalist who introduced the tree to France in the 19th century.

Accessions

North America
Europe

Nurseries

North America

Seed suppliers

References

  1. ↑ 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. ↑ 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
  3. ↑ Ware, G. (1995). Little-known elms from China: landscape tree possibilities. Journal of Arboriculture, (Nov. 1995). International Society of Arboriculture, Champaign, Illinois, USA.
  4. ↑ 4.0 4.1 Morton Arboretum Quarterly 31: 1-9, 1995
  5. ↑ 5.0 5.1 Brookes, A. H. (2012). Disease-resistant elm cultivars, Butterfly Conservation trials report, 2nd revision, 2012. Butterfly Conservation, Hants & IoW Branch, England.
  6. ↑ 6.0 6.1 D'Amato, N. & Sydnor, T. (2005). David Elm use for increasing biodiversity, Columbus, Ohio, USA.
  7. ↑ Struve, D. K. and Rhodus, T. (1990). Turning copper into gold. Amer. Nurseryman, 172: 114-123.
  8. ↑ Johnson, O. (2011). Champion Trees of Britain & Ireland, p. 168. Kew Publishing, Kew, London. ISBN 9781842464526.

Further reading