Siberian Elm

''Ulmus pumila'', the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes mistakenly called the "Chinese" elm (''Ulmus parvifolia''). ''U. pumila'' has been widely cultivated throughout Asia, North America, Argentina, and southern Europe, becoming naturalized in many places, notably across much of the United States.

Description

The Siberian elm is usually a small to medium-sized, often bushy, deciduous tree growing to tall, the diameter at breast height to . The bark is dark gray and irregularly longitudinally fissured. The branchlets are yellowish gray, glabrous or pubescent, unwinged, and without a corky layer, with scattered lenticels. The winter buds are dark brown to red-brown, globose to ovoid. The petiole is and pubescent; the leaf blade is elliptic-ovate to elliptic-lanceolate, , the colour changing from dark green to yellow in autumn.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, US

/ref> The perfect flower, perfect, apetalous, wind-pollinated flowers bloom for one week in early spring, before the leaves emerge, in tight fascicles (bundles) on the last year's branchlets. Flowers emerging in early February are often damaged by frost (causing the species to be dropped from the Dutch elm breeding programme).Went, J. (1954). The Dutch Elm Disease – Summary of fifteen years' hybridization and selection work (1937–1952). ''European Journal of Plant Pathology''. 02(1954); 60(2): 109–1276. Each flower is about across and has a green calyx with four or five lobes, four to eight stamens with brownish-red anthers, and a green pistil with a two-lobed style. Unlike most elms, the Siberian elm is able to self-pollinate successfully.

The wind-dispersed samarae are whitish tan, orbicular to rarely broadly obovate or elliptical, , and glabrous except for pubescence on the stigmatic surface; the stalk is , and the perianth is persistent. The seed is at the centre of the samara or occasionally slightly toward the apex, but does not reach the apical notch. Flowering and fruiting occur from March to May. Ploidy: 2''n'' = 28. The tree also suckers readily from its roots.Grbić, M., Skočajić, D., Đukić, M., Đunisijević-Bojović, D., Marković, M. (2015). 'Mass clonal propagation of elm as a way for replacement of endangered autochthonous species'. p.62. ''Proceedings, International Conference Reforestation Challenges, 3–6 June 2015, Belgrade, Serbia.''

The tree is short-lived in temperate climates, rarely reaching more than 60 years of age, but in its native environment, may live between 100 and 150 years. A giant specimen, southeast of Khanbogt in the south Gobi, with a girth of in 2009, may exceed 250 years (based on average annual ring widths of other ''U. pumila'' in the area).

비술나무 줄기.JPG, alt=Bark of mature tree, Korea, Bark (Korea)
U. pumila growth rings 2, Knowsley Park Portsmouth.jpg, Stump showing rapid stem diameter increase (> per annum)
Ulmus pumila leaves.jpg, Summer foliage
비술나무 잎가지.JPG, Typical 'long shoots' of pendulous forms
Ulmus pumila (5107823814).jpg, Axil buds and fawn-coloured twigs
U.pumila cvasti.jpg, Flowers
Elm in beijing.JPG, Immature fruits (and '' Satyrium w-album'' larva)
File:Ulmus-pumila-samaras.jpg, Mature fruits

Taxonomy

The species was described by Peter Simon Pallas in the 18th century from specimens from Transbaikal.

Two varieties were traditionally recognized: ''U. p. ''var.'' pumila'' and ''U. p.'' var. ''arborea'', but the latter is now treated as a cultivar, ''U. pumila'' 'Pinnato-ramosa'.

Distribution and habitat

The tree is native to Central Asia, eastern Siberia, the Russian Far East, Mongolia, Tibet, northern China, India (northern Kashmir), and Korea. It is the last tree species encountered in the semidesert regions of Central Asia.

Ecology

Pests and diseases

The tree has considerable variability in resistance to Dutch elm disease; for example, trees from north-western and north-eastern China exhibit significantly higher tolerance than those from central and southern China. Moreover, it is highly susceptible to damage from many insects and parasites, including the elm leaf beetle ''Xanthogaleruca luteola'', the Asian 'zigzag' sawfly '' Aproceros leucopoda'', Elm Yellows, powdery mildew, cankers, aphids, leaf spot and, in the Netherlands, coral spot fungus '' Nectria cinnabarina''. ''U. pumila'' is the most resistant of all the elms to verticillium wilt.

Invasiveness and spontaneous hybridization

In North America, ''U. pumila'' has become an invasive species in much of the region from central Mexico northward across the eastern and central United States to Ontario, Canada.McIlvain, E. H. & Armstrong, C. G. (1965). Siberian Elm: A Tough New Invader of Grasslands. ''Weeds'', Vol. 13, No. 3 (July 1965), pp 278 – 279. Weed Science Society of America & Allen Press. It also hybridizes in the wild with the native '' U. rubra'' (slippery elm) in the central United States, prompting conservation concerns for the latter species.Elowsky, C. G., Jordon-Thaden, I. E., & Kaul, R. B. (2013). A morphological analysis of a hybrid swarm of native ''Ulmus rubra'' and introduced ''U. pumila'' (Ulmaceae) in southern Nebraska. ''Phytoneuron'' 2013-44: 1–23. . In South America, the tree has spread across much of the Argentine pampas.Villamil, C. B., Zalba, S. M. ''Red de información sobre especies exóticas invasoras – I3N-Argentina'' Universidad Nacional del Sur Bahía Blanca, Argentina.Hiersch, H., Hensen, I., Zalapa, J. Guries, R. & Brunet, J. (2013). Is hybridization a necessary condition for the evolution of invasiveness in non-native Siberian elm? ''Abstracts. Third International Elm Conference 2013. The elm after 100 years of Dutch elm disease''. Florence, p45.

In Europe, it has spread widely in Spain, and hybridizes extensively there with the native field elm (''U. minor''), contributing to conservation concerns for the latter species. Research is ongoing into the extent of hybridisation with ''U. minor'' in Italy. In the Netherlands, 1700 Siberian elms planted in error for field elm in 2016 in the Zalkerbos near Kampen, Overijssel, were grubbed up because of invasiveness concerns and replaced in 2023 with native species.

''U. pumila'' is often found in abundance along railroads and in abandoned lots and on disturbed ground. The gravel along railroad beds provides ideal conditions for its growth - well-drained, nutrient-poor soil, and high light conditions; these beds provide corridors that facilitate its spread. It is found as high as 8000 feet in the Sandia Mountains in New Mexico and is invading coniferous forest there. New Mexico may be a center of genetic diversity in North America. Owing to its high sunlight requirements, it seldom invades mature forests, and is primarily a problem in cities and open areas,National Audubon Society (2002). ''Field Guide to North American Trees'', Western Region, p. 419-420 as well as along transportation corridors.

The species is now listed in Japan as an alien species recognized as established in Japan or found in the Japanese wild.

Cultivation

''U. pumila'' was introduced into Spain as an ornamental, probably during the reign of Philip II (1556–98), and from the 1930s into Italy. In these countries, it has naturally hybridized with the field elm (''U. minor''). In Italy, it was widely used in viniculture, notably in the Po River Valley, to support the grape vines until the 1950s, when the demands of mechanization made it unsuitable.

Three specimens were supplied by the Späth nursery of Berlin to the Royal Botanic Garden Edinburgh (RBGE) in 1902 as ''U. pumila'', in addition to specimens of the narrow-leaved ''U. pumila'' cultivar 'Pinnato-ramosa'. One was planted in RBGE; the two not planted in the Garden may survive in Edinburgh, as it was the practice of the Garden to distribute trees about the city. Kew Gardens obtained specimens of ''U. pumila'' from the Arnold Arboretum in 1908 and, as ''U. pekinensis'', via the Veitch Nurseries in 1910 from William Purdom in northern China. A specimen obtained from Späth and planted in 1914 stood in the Ryston Hall arboretum, Norfolk, in the early 20th century. The tree was propagated and marketed by the Hillier & Sons nursery, Winchester, Hampshire, from 1962 to 1977, during which time over 500 were sold.Hillier & Sons (1977). ''Catalogue of Trees & Shrubs''. Hillier, Ampfield, UK.Hillier & Sons ''Sales inventory 1962 to 1977'' (unpublished). More recently, the popularity of ''U. pumila'' in the Great Britain has been almost exclusively as a bonsai subject, and mature trees are largely restricted to arboreta. In the UK the TROBI Champions grow at Thorp Perrow Arboretum, Yorkshire, × in 2004, and at St Ann's Well Gardens, Hove, Sussex × in 2009.Johnson, O. (ed.). (2011). ''Champion Trees of Britain & Ireland''. Royal Botanic Gardens, Kew, London.

''U. pumila'' is said to have been introduced to the US in 1905 by Prof. John George Jack, and later by Frank Nicholas Meyer, though 'Siberian elm' appears in some 19th-century US nursery catalogues. The tree was cultivated at the United States Department of Agriculture (USDA) Experimental Station at Mandan, North Dakota, where it flourished.Klingaman, G. (1999). Plant of the Week: Siberian Elm. ''Extension News'', University of Arkansas, Division of Agriculture. It was consequently selected by the USDA for planting in shelter belts across the prairies in the aftermath of the Dustbowl disasters, where its rapid growth and tolerance for drought and cold initially made it a great success. However, the species later proved susceptible to numerous maladies. Attempts to find a more suitable cultivar were initiated in 1997 by the Plant Materials Center of the USDA, which established experimental plantations at Akron, Colorado, and Sidney, Nebraska. The study, no. 201041K, was to conclude in 2020. The US National Champion, measuring high in 2011, grows in Berrien County, Michigan.American Forests. (2012). The 2012 National Register of Big Trees.

The seeds lose their viability rapidly after maturity unless placed on suitable germination conditions or dried and placed at low temperatures.Hirsch, H., Wypior, C., Wehrden, H., Wesche, K., Renison, D, and Hensen, I. (2012). Germination performance of native and non-native ''Ulmus pumila'' populations. ''Neobiota 15'', 53–68. 14 Dec. 2012. The species has a high sunlight requirement and is not shade-tolerant; with adequate light, it exhibits rapid growth. The tree is also fairly intolerant of wet ground conditions, growing better on well-drained soils. While it is very resistant to drought and severe cold, and able to grow on poor soils, its short period of dormancy, flowering early in spring followed by continuous growth until the first frosts of autumn, renders it vulnerable to frost damage.

As an ornamental, ''U. pumila'' is a very poor tree, tending to be short-lived, with brittle wood and poor crown shape, but it has nevertheless enjoyed some popularity owing to its rapid growth and provision of shade. The Siberian elm has been described as "one of the world's worst... ornamental trees that does not deserve to be planted anywhere". Yet in the US during the 1950s, the tree was also widely promoted as a fast-growing hedging substitute for privet, and as a consequence is now commonly found in nearly all states.

File:Marche Pesaro Olmo siberiano 08L76402G479PU11.jpg, Siberian elm, Pesaro, Italy (2019)
File:Sibirski brest pionirski park.JPG, Cultivated form, Pioneers Park, Belgrade
File:Ulmus pumila.jpg, Typical cultivated specimen, Morton Arboretum
File:RN Ulmus pumila.JPG, Compact form, Groningen
File:U. pumila Knowsley Park Portsmouth.jpg, Felled by Force 8 gale, Portsmouth, UK

Cultivars

Valued for the high resistance of some clones to Dutch elm disease, over a dozen selections have been made to produce hardy ornamental cultivars, although several may no longer be in cultivation:

A variegated weeping elm, with cream, dark green, and light green variegation, is cultivated in China as ''Ulmus pumila'' 'Variegata'.

Some authorities consider the cultivar ' Berardii' a form of ''U. pumila''.Krüssmann, Gerd, ''Manual of Cultivated Broad-Leaved Trees & Shrubs'' (1984 vol. 3) Nottingham elm, considered an '' Ulmus × hollandica'' by Richens, was marketed from the 19th century as 'Siberian elm'.

Hybrid cultivars

* Androssowii, ''U.'' × ''arbuscula'', Fuente Umbria, Karagatch, Toledo

The species has been widely hybridized in the United States and Italy to create robust trees of more native appearance with high levels of resistance to Dutch elm disease:
* Arno, Cathedral, Coolshade, Fiorente, Homestead, Lincoln, Morton Plainsman = , Morton Stalwart = , New Horizon, Plinio, Rebona, Regal, Recerta, Rosehill, San Zanobi, Urban, Willis, Dutch clone '260' (not released to commerce).

Other hybrid cultivars involving crossings with ''U. pumila'':
* Den Haag, Sapporo Autumn Gold

Uses

The unripe seeds have long been eaten by the peoples of Manchuria, and during the Great Chinese Famine, they also became one of the most important foodstuffs in the Harbin region. The leaves were also gathered, to the detriment of the trees, prompting a prohibition order by the authorities, which was largely ignored. The leaves eaten raw are not very palatable, but stewed and prepared with kaoliang or foxtail millet make a better-tasting and more filling meal.Baranov, A. L. (1962). On the economic use of wild plants in N. E. China. ''Quarterly Journal of the Taiwan Museum'', 15 (122), 1962, 107–115.

In literature and travel writing

The "dwarf-" or "shrub-elms" of the North Caucasus, along with other local flora, appear in the opening description of Tolstoy's story "The Raid" (1853).

Nicholas Roerich describes a specimen discovered on his travels through Mongolia:

We are in the deserts of Mongolia. It was hot and dusty yesterday. From far away, thunder was approaching. Some of our friends became tired from climbing the stony holy hills of Shiret Obo. While already returning to the camp, we noticed in the distance a huge elm tree – ''karagatch'', - lonely, towering amidst the surrounding endless desert. The size of the tree, its somewhat familiar outlines attracted us into its shadow. Botanical considerations led us to believe that in the wide shade of the giant there might be some interesting herbs. Soon, all the co-workers gathered around the two mighty stems of the ''karagatch''. The deep, deep shadow of the tree covered about 50 feet across. The powerful tree-stems were covered with fantastic burr growths. In the rich foliage, birds were singing and the beautiful branches were stretched out in all directions, as if wishing to give shelter to all pilgrims.

Accessions

North America

* Arnold Arboretum, US. Acc. nos. 17923, 638-79, 673-87.
* Denver Botanic Gardens, US. Acc. no. 900534.
* Dominium Arboretum, Ottawa, Ontario, Canada. No acc. details available.
* Holden Arboretum, US. Acc. nos. 99-868, 72-218
* Longwood Gardens, US. Acc. no. 1962-0512.
* Morton Arboretum, US. Acc. nos. 542-49
325-70
53-74, 172-U.
* UBC Botanical Garden and Centre for Plant Research, US. Acc. no. 027560-0284-1989.

Europe

* Arboretum of Warsaw University of Life Sciencesbr>
University of Life Sciences, Warsaw, Poland. 2 trees, no accession details available.
* Brighton & Hove City Council, UK. NCCPG Elm Collection.
* Dubrava Arboretum, Lithuania. No details available.
* Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 521.
* Hergest Croft Gardens, Herefordshire, UK. One tree, no accession details available.
* Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18162,3,4.
* Royal Botanic Gardens, Wakehurst Place, UK. Acc. no. 2000-4449.
* Sir Harold Hillier Gardens. Acc. no. 2016.0386, grown from seed of tree in Utah, US.
* Tallinn Botanic Garden, Estonia

No accession details available.
* Thorp Perrow Arboretum, Yorkshire, UK. British Champion tree, 19 m high, 70 cm d.b.h. in 2004.
* Westonbirt Arboretumbr>
Tetbury, Glos., UK. Two trees planted 1981, no acc.details.
* Wijdemeren City Council, Netherlands. Elm Arboretum. ''U. pumila'' 'Puszta' planted Smeerdijkgaarde, Kortenhoef 2013; Dammerweg, Nederhorst den Berg 2015. 5 'Aurescens' planted 2015 Overmeerseweg, 'Pinnato-ramosa' planted 2015 Dammerweg, 'Mierenbos' and 'Poort Bulten' planted Brilhoek and cemetery Hornhof, Nederhorst den Berg in 2019

Australasia

* Alma Park, St Kilda, Victoria, Australia. One specimen, listed on the National Trust of Victoria's Significant Tree Register.
* Eastwoodhill Arboretumbr>
Gisborne, New Zealand, Gisborne, New Zealand. 2 trees, details not known.

Africa

* Arboretum of Haramaya University, Haramaya, Ethiopia Hedberg, I., Friis, I. & Persson, E. (2009). Flora of Ethiopia and Eritrea 1: 1-305; powo.science.kew.org
/ref>

Nurseries

Europe

*Van Den Berk (UK) Ltd.

London, UK

References

External links

* North Dakota State University: trees handbook
''Siberian elm'' pages

* Evaluation of the Siberian Elm (''Ulmus pumila''), USDA
pages 42, 43



Diagnostic photographs; specimen at Morton Arboretum
*


Northeast China.

''Ulmus pumila''
- information, genetic conservation units and related resources. European Forest Genetic Resources Programme (EUFORGEN)
''U. pumila'', Flora of China, www.efloras.org''U. pumila'', Flora of North America, www.efloras.org

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pumila
Garden plants of Asia
Ornamental trees
Plants described in 1753
Taxa named by Carl Linnaeus
Ulmus articles with images
Elm species and varieties
Flora of the Russian Far East
Trees of China
Trees of Korea
Trees of Mongolia
Trees of Siberia