''Ulmus microcarpa'' was named and first described by the Chinese botanist L. K. Fu, who discovered the tree in the Chayu broad-leaved forests of south-eastern Xizang at altitudes of around 2800 m during the 1973 Qinghai - Tibet Expedition.Fu, L. K. (1979). Chinese plant database and catalogue - Ulmus microcarpa. ''Acta Phytotaxonomica Sinica'' 17(1): 48–49, pl. 2, f. 5–8, 48 1979, Beijing, China Unlike the majority of Tibet, the Chayu region has a subtropical highland climate featuring warm, wet, summers and mild, dry, winters (avg. annual rainfall 807 mm). Commonly known as the Tibetan Elm, the tree was introduced to the United States in 2006, and the UK in 2013; it remains one of the rarest species of elm in cultivation.

Description

''U. microcarpa'' can reach a height of 30 m in the wild, the trunk < 80 cm

d.b.h. Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements. Tree trunks are measured at the height of an adult's breast, ...

The large oblong to elliptic leaves are 8.5–17 cm long by 5–8 cm broad with 5 mm petioles, likened by Fu to those of ''U. wallichiana'' and ''U. bergmanniana'' var. ''lasiophylla'', but much smaller on juvenile plants. As its specific epithet implies, the suborbicular, glabrous samarae are small, 7–8 mm long by 7–8 mm wide, the seed at the centre.

Ploidy Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Sets of chromosomes refer to the number of mat ...

: ''2n'' = 28.Fu, L. K., 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, US

/ref> Growth in the UK has been slow, the branches on juvenile trees increasing in length by no more than 10–12 cm per annum on moist, fertile soil. The species is the first to leaf in spring in the UK, and the first to defoliate in autumn, usually by late September.Brookes, A. (2017). ''Great Fontley Elm Trial Report 2017''.

Butterfly Conservation Butterfly Conservation (BC) is a UK-wide nonprofit environmentalist organization and charity dedicated to conserving butterflies, moths, and the environment. The charity uses its research to provide advice on how to conserve and restore butterfly ...

, Lulworth, UK. File: U. microcarpa foliage detail.jpg, Foliage detail, Great Fontley, UK File:Ulmus microcarpa, last and previous year's growth.jpg, Last and previous year's branchlet growth File:Ulmus microcarpa emergent leaves March week 1.jpg, Leaf buds, March week 1

Pests and diseases

No information available; ''U. microcarpa'' was not known in the United States when the majority of Asiatic elms were screened for resistance to Dutch elm disease by the late

George Ware George Ware, Ph.D. (1924–2010) was an American dendrologist and former research director of the Morton Arboretum Illinois who specialized in the evaluation of Asiatic species of elm as urban trees.''Chicago Suburban Daily Herald'', 7 July 2010. ...

at the Morton Arboretum, Illinois, in the early 1990s.Ware, G. (1995). Little known elms from China: landscape tree possibilities. ''Journal of Arboriculture''. 21(6), 284–288. November 1995.

Cultivation

''U. microcarpa'' is very rare in cultivation outside

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, and accessions are (2019) restricted to two arboreta in the United States and four in the UK. The tree was one of 12 Chinese species under evaluation at the Morton Arboretum, Illinois, in 2009 by the late Dr

.Dirr, M. (2009). 'Future Tree Selections'. ''Western'', Spring 2009, p.8. Western Nursery & Landscape Association, St Joseph, Missour

/ref>

Accessions

;North America *

Brenton Arboretum The Brenton Arboretum is a 141-acre arboretum and public garden in Dallas Center, Iowa, United States, established in 1997. The arboretum displays 175 native Iowa trees and shrubs suitable to the site, as well as many other tree species which can ...

, US. Acc. no. 06–035; from the Morton Arboretum (see below). * Morton Arboretum, US. Acc. nos. 362–2006, 588–2006, from seed wild collected in Tibet by the Chinese Academy of Forestry, Research Institute of Forestry Tibet Autonomous Region, China. ;Europe * Grange Farm Arboretum, Lincolnshire, UK. Rooted cuttings from Brenton Arboretum, acquired 2013. Acc. no. 1076. * Royal Botanic Garden Edinburgh, UK. One small rooted cutting acquired 2014. Acc. no. 20141572.Royal Botanic Garden Edinburgh. (2017). ''List of Living Accessions: Ulmus'

/ref> *

Sir Harold Hillier Gardens The Sir Harold Hillier Gardens is an arboretum comprising 72 hectares (180 acres) accommodating over 42,000 trees and shrubs in about 12,000 taxa, notably a collection of oaks, camellia, magnolia and rhododendron. The Gardens are located nor ...

, Ampfield, Hampshire, UK. Rooted cutting in propagation unit (2018), acc. no. 2017.0196 *

Wijdemeren City Council Wijdemeren () is a municipality in the Netherlands, in the province of North Holland, on the western border of the Gooi region. Wijdemeren contains many lakes. In the north(east) ''Spiegelplas'' and ''Ankeveense Plassen'', in the (south)west ''Loo ...

, Netherlands. 2 trees planted 2019 cemetery Hornhof,

Nederhorst den Berg Nederhorst den Berg () is a village in the province of North Holland, Netherlands. It lies about 8 km northwest of Hilversum in the Vechtstreek area, near the Vecht river. Until 1 January 2002, it was a separate municipality; it is now part ...

References

External links

Photographs labelled ''U. microcarpa'' on Plant Photo Bank of China, ppbc.iplantefloras.org: ''U. microcarpa'' description

efloras.org: ''U. microcarpa'' leaves and fruit illustration, figures 4 to 7
{{Taxonbar, from=Q7879512 Elm species and varieties Flora of China Trees of China Flora of Tibet Trees of Asia Ulmus articles with images microcarpa Taxa named by Li Kuo Fu