Ulmus crassifolia

Ulmus crassifolia
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Rosales
Family:	Ulmaceae
Genus:	Ulmus
Species:	U. crassifolia
Binomial name
Ulmus crassifolia Nutt.
Natural range (Florida population excluded)
Synonyms
Ulmus monterreyensis Mull. Ulmus opaca Nutt.

Ulmus crassifolia Nutt., the Texas cedar elm or simply cedar elm, is a deciduous tree native to south central North America, mainly in southern and eastern Texas, eastern Oklahoma, Arkansas and Louisiana, with small populations in western Mississippi, southwest Tennessee and northwestern Florida;^[1] it also occurs in northeastern Mexico.^[2][3] The tree typically grows well in flat valley bottom areas referred to as 'Cedar Elm Flats'. The common name 'cedar elm' is derived from the trees' association with juniper trees, locally known as cedars.^[4]

Description

The cedar elm is a medium-sized to large deciduous tree growing to 24–27 m tall with a rounded crown. The leaves are small, 2.5–5 cm long by 1.3–2 cm broad, with an oblique base, and distinguish it from Ulmus serotina with which it readily hybridizes in the wild. Leaf fall is late, often in early winter. The wind-pollinated apetalous perfect flowers are produced in the late summer or early fall; they are small and inconspicuous, with a reddish-purple color. The fruit is a small winged samara 8–10 mm long, maturing quickly after the flowering in late fall.^[5][6]

Ulmus crassifolia bark

Pests and diseases

Cedar elm is susceptible to Dutch elm disease (DED), though less so than American elm, and moderately damaged by the elm leaf beetle Xanthogaleruca luteola. The tree also suffers from a vascular wilt, the symptoms often confused with those of DED, whilst in Texas it is damaged by Spanish moss Tillandsia usneoides, which drapes across the branches weakening the tree, occasionally killing it.^[7][8]

Cedar elms are very susceptible to mistletoe. Mistletoe is a parasite that roots itself in to the vascular system of the tree, thus stealing valuable nutrients and water. In some cases, if not removed the parasite can be devastating to large sections of trees and even fatal. They create club like branches that die out at the ends. These "club" branches create openings for future pests like the elm beetles and carpenter ants. There are no known treatments that are safe enough to kill mistletoe without killing the tree. Removing the mistletoe manually is not a guarantee, however it is the best known method for control.

Cultivation

Owing to Dutch elm disease, the cedar elm is now rarely cultivated in North America. It is extremely rare in cultivation in Europe,^[9] and Australasia.^[10]

Notable trees

The USA National Champion, measuring 37 m high in 2001, grows in the Meeman-Shelby Forest State Park Tennessee.^[11]

Cultivars

• Brazos Rim.

Hybrids

• Ulmus × arkansana

Accessions

North America

• Arnold Arboretum. Acc. nos. 511-2002, 758-86, both wild collected.
• Chicago Botanic Garden, Glencoe, Illinois. No details available.
• Bartlett Tree Experts. Acc. no. 90-1243, unrecorded provenance.
• Morton Arboretum. Acc. no. 385-68,^[12] 14-86
• New York Botanical Garden. Acc. no. 79617, unrecorded provenance.
• U S National Arboretum,^[13] Washington, D.C., USA. Acc. no. 37834

Europe

• Grange Farm Arboretum, Sutton St. James, Spalding, Lincolnshire, UK. Acc. no. 509
• Royal Botanic Garden Edinburgh. Acc. no. 20080090, from seed wild collected in USA.
• Sir Harold Hillier Gardens, UK. Acc. no. 1980-0443, (Brentry Field).
• University of Copenhagen Botanic Garden. No details available.

Australasia

• Manukau Cemetery & Crematorium, Auckland, New Zealand. No details available.

Nurseries

North America

Widely available

Europe

• Arboretum Waasland,^[14] Nieuwkerken-Waas, Belgium.

Australasia

None known.

References

1. "Map: Ulmus crassifolia". Efloras.org. Retrieved 2013-09-01.
2. Todzia, C. A. & Panero, J. L. (2006). A new species of Ulmus (Ulmaceae) from southern Mexico and a synopsis of the species in Mexico. Brittonia, Vol 50, (3): 346
3. "A New Species of Ulmus (Ulmaceae) from Southern Mexico and a Synopsis of the Species in Mexico". Jstor.org. Retrieved 2013-11-30.
4. http://npsot.org/wp/story/2011/1687/
5. "Ulmus crassifolia in Flora of North America @". Efloras.org. Retrieved 2013-09-01.
6. "Plants Profile for Ulmus crassifolia (cedar elm)". Plants.usda.gov. Retrieved 2013-09-01.
7. "Ulmus crassifolia Nutt". Na.fs.fed.us. Retrieved 2013-09-01.
8. Archived March 31, 2012, at the Wayback Machine.
9. Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. 1848–1929. Republished 2004 Cambridge University Press, ISBN 9781108069380
10. Auckland Botanical Society (2003). Journal Vol. 58 (1), June 2003. ISSN 0113-4132
11. American Forests. (2012). The 2012 National Register of Big Trees.
12. "''Ulmus crassifolia'' at Morton Arboretum". Cirrusimage.com. 2010-05-06. Retrieved 2013-09-14.
13. Ramon Jordan. "US National Arboretum :". Usna.usda.gov. Retrieved 2013-09-01.
14. "English". Arboretum-waasland.be. Retrieved 2013-09-01.