|U. alata leaves. Photo: R. Nijboer.|
As its common and scientific names imply, Ulmus alata is most easily recognized by the very broad, thin pair of corky wings that form along the branchlets after a couple of years. The tree generally grows to a maximum height and breadth of about 13 × 13 m, although on fertile alluvial soils such as those of the Mississippi River Delta, some specimens have reached treble this height (see 'Notable trees' below). The crown can be either rounded or pyramidal; the branches are pendulous.
The leaves are comparatively small for the genus, < 6.5 cm (2.5 in) long and < 2.0 cm (0.8 in) broad, oblong-lanceolate to narrowly elliptic, thin in texture, and smooth above. The wind-pollinated perfect apetalous flowers are borne on long pedicels in March and April before the leaves appear. The reddish samarae are also relatively small, < 8 mm long, narrowly elliptic with two long incurving stigmas at the tip, and usually disperse before the end of April.
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Ulmus alata is tolerant of a wide range of soils, and of ponding, but is the least shade-tolerant of the North American elms. Its growth rate is often very slow, the trunk increasing in diameter by < 5mm (0.2 in) per annum. The species is occasionally considered a nuisance as it readily invades old fields, forest clearings, and rangelands, proving particularly difficult to eradicate with herbicides.
Pests and diseases
Ulmus alata is rarely cultivated beyond its natural range. It remains in commercial production in the USA, and is occasionally available in Europe; several specimens are also grown in New Zealand.
Ulmus alata is of minimal commercial significance, its hard timber considered no more remarkable than that of other American elms, and of limited use because of the commonly small size of the trees. However, owing to its resistance to splitting, it is used to make high-quality hockey sticks.
On the silty uplands of the Mississippi Delta, Ulmus alata can attain 27 m (89 ft) in height, although the trunk diameter rarely exceeds 60 cm (24 in) d.b.h. In the old growth Fernbank Forest in Atlanta, Georgia, the species attains heights up to 126 feet (38 m). The tallest known extant individual, at 131 feet (40 m),[when?] is in the Congaree National Park in South Carolina.
- North America
- Arnold Arboretum. Acc. no. 404-95, wild collected.
- Bartlett Tree Experts . Acc. no. 1438, unrecorded provenance.
- Brooklyn Botanic Garden , New York. Acc. nos. 730275, X00886
- Bernheim Arboretum and Research Forest , Clermont, Kentucky. No details available.
- Morton Arboretum. Acc. no. 116-96, wild collected Papoose Lake, Illinois.
- Brighton & Hove City Council, UK, NCCPG Elm Collection . One tree at East Brighton Park, UK champion 13 m high, 31 cm d.b.h. in 2001.
- Grange Farm Arboretum, Sutton St James, Spalding, Lincolnshire, UK. Acc. no. 506
- Royal Botanic Garden Edinburgh. Acc. no. 20080092, from seed wild collected in USA.
- Thenford House, Northamptonshire, UK. No details available.
- Manukau Cemetery & Crematorium, Auckland, New Zealand. No details available.
- North America
- Arboretum Waasland, Nieuwkerken-Waas, Belgium.
- Grange Farm Plants, Spalding, Lincolnshire, UK.
- Plantentuin Esveld, Netherlands.
- "Alata" means "winged".
- Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848-1929. Private publication. 
- Schnelle, M. (1999). Field Notes: Ulmus alata. American Nurseryman, page 1998, 1st March, 1999. p. 98. Chicago
- University of Florida, Environmental Horticulture Department (1994). Fact Sheet ST-648. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences.
- "Elm Phloem Necrosis".
- Auckland Botanical Society (2003). Journal Vol. 58 (1), June 2003. ISSN 0113-41332
- Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 978-1-873580-61-5.
- http://www.na.fs.fed.us/spfo/pubs/silvics_manual/Volume_2/ulmus/alata.htm Ulmus alata Michx.