Ulmus davidiana
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 David Elm, Great Fontley, England.
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| Ulmus davidiana Planch. |
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The David Elm, Ulmus davidiana Planch., is a small deciduous tree widely distributed across China, Mongolia, Korea, Siberia and Japan, where it is found on wetlands along streams at elevations of between 2000 m and 2300 m.[1] It grows to a maximum height of 15 m, with a slender trunk of no more than 0.3 m d.b.h. (diameter at breast height); the bark is longitudinally fissured. The leaves are obovate to obovate-elliptic < 10 cm x < 5 cm, with a rough upper surface. The wind-pollinated petal-less flowers are produced on second-year shoots in spring, followed by samarae that are obovate < 19 mm long by < 14 mm wide.
The tree is uncommonly cultivated in the West, being unsuited to all but very sheltered, humid conditions, and is intolerant of ponding. Evaluated with other Chinese elms at the Morton Arboretum, Illinois it was found to have a good resistance to Dutch elm disease, elm leaf beetle, and elm yellows. It was also considered to have a remarkable resemblance to the American Elm U. americana in all but ultimate size.[2]
However, 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 it bending to the ground[3] ("Pruning can help the plant result in a more structurally stable branching pattern" [4]).
There are no known cultivars of this taxon, nor is it known to be available from any nurseries beyond the USA.
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[edit] 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).[4][5] 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 of 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).
[edit] Subspecies & varieties
Two varieties are recognized: var. davidiana L.K.Fu, and var. japonica Rehder, the Japanese Elm.
[edit] Arboreta etc. accessions
- North America
- Arnold Arboretum, acc. nos. 5957 (wild collected), 785-80 (cult. from wild material).
- Brenton Arboretum, Dallas Center, Iowa. No details available.
- Chicago Botanic Garden, Glencoe, Illinois. Five trees, no other details available.
- Dawes Arboretum [4], Newark, Ohio. 2 trees, no acc. details available.
- Denver Botanic Gardens, acc. no. 950870. No details available.
- Holden Arboretum, acc. no. 00-318, 3 specimens wild collected.
- Morton Arboretum, Illinois, acc. no. 427-84
- Europe
- Brighton & Hove City Council, UK, NCCPG elm collection [5]. Stanmer Park, UK champion tree, 7 m high, 40 cm d.b.h. in 2002 [6].
- Grange Farm, Sutton St. James, Spalding, Lincolnshire, UK, acc. no. 510
- Great Fontley Farm, Fareham, UK, Butterfly Conservation Elm Trials plantation, Home Field E6, E8, K9, Platts M10, (planted 2002).
- Hortus Botanicus Nationalis, Salaspils, Latvia acc. no. 18095
- Oxford University Botanic Garden, UK, acc. no. 0004891.
- Royal Botanic Garden Edinburgh, UK, acc. nos. 20021373, 20030905 grown from seed collected Liaoning, China, and wild collected in Korea resp.
- Strona Arboretum [6], University of Life Sciences, Warsaw, Poland.
[edit] Nurseries
- North America
[edit] Seed suppliers
- B and T World Seeds, Paguignan, 34210 Aigues-Vives, France [8]
- Sandeman Seeds, 7 Route de Burosse, 64350 Lalongue, France [9]
[edit] Etymology
The tree is named for Father Armand David, the French missionary and naturalist who introduced the tree to France in the 19th century.
[edit] References
- ^ 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. [1]
- ^ Ware, G. (1995). Little-known elms from China: landscape tree possibilities. Journal of Arboriculture, (Nov. 1995). International Society of Arboriculture, Champaign, Illinois, USA. [2]
- ^ 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, UK.
- ^ a b D'Amato, N. & Sydnor, T. (2005). David Elm use for increasing biodiversity, Columbus, Ohio, USA. [3]
- ^ Struve, D. K. and Rhodus, T. (1990). Turning copper into gold. Amer. Nurseryman, 172: 114-123.
- ^ Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 9781873580615.
