Ulmus davidiana var. japonica 'Thomson'

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Ulmus davidiana var. japonica 'Thomson'
Variety Ulmus davidiana var. japonica
Cultivar 'Thomson'
OriginPFRA Nursery, Saskatchewan, Canada

Ulmus davidianavar.japonica 'Thomson' is a hardy, cold-resistant cultivar of the Japanese Elm assessed by the Prairie Farm Rehabilitation Administration (PFRA) Nursery (now the AAFC-PFRA&E Shelterbelt Centre) at Indian Head, Saskatchewan, in the 1970s as part of its shelterbelt tree research. [1] [2] . [3]

Contents

The tree was one of a number of Japanese Elms planted in an experimental shelterbelt at Indian Head in 1953. These shelterbelt trees were derived from seed taken from two openly pollinated Japanese Elms obtained from Manchuria and planted at Indian Head in 1929. 'Thomson' attained a height of 8 m in 25 years, a rather modest performance compared with Siberian Elm Ulmus pumila and American Elm Ulmus americana grown at the same site. Nevertheless, the tree has proved exceptionally hardy. [1]

Description

'Thomson' is distinguished by a single trunk bearing a vase-shaped crown, the branches forming strong wide-angled crotches; the bark is dark grey and deeply fissured. [4] The twigs have diamond-shaped fissures that become more apparent on second-year wood, and occasionally sport corky wings. The leaves are borne on 1 cm petioles, and average 7.5 cm in length, obovate to elliptic, with the typical acuminate apex and oblique base; dark green and glabrous, they turn bright yellow in autumn. The samarae are obovate and deeply notched at the apex. [1]

The species does not sucker from roots. [5]

Pests and diseases

'Thomson' displayed a resistance to Dutch elm disease when inoculated by Dr E. S. Kondo of the Canadian Forest Service (CFS) in Sault Ste. Marie; the original tree still survives (2008) and has also proven resistant to elm leaf beetle Xanthogaleruca luteola . Moreover, the tree's foliage was adjudged "resistant" to Black Spot by the Plant Diagnostic Clinic of the University of Missouri .

Cultivation

The tree was usually propagated by grafting on Siberian Elm seedlings. Released for sale in Saskatchewan in 1980, [1] 'Thomson' is no longer in commerce owing to restrictions imposed by the Canadian government on the movement of elms across the country, which severely limited its potential market. 'Thomson' was never introduced to Europe or Australasia.

Synonymy

Etymology

The tree was named for Mr W. B. Thomson, appointed director of PFRA in 1973.

Accessions

North America

Related Research Articles

<i>Ulmus davidiana <span style="font-style:normal;">var.</span> japonica</i> Variety of tree

Ulmus davidiana var. japonica, the Japanese elm, is one of the larger and more graceful Asiatic elms, endemic to much of continental northeast Asia and Japan, where it grows in swamp forest on young alluvial soils, although much of this habitat has now been lost to intensive rice cultivation.

<i>Ulmus laciniata</i> Species of tree

Ulmus laciniata(Trautv.) Mayr, known variously as the Manchurian, cut-leaf, or lobed elm, is a deciduous tree native to the humid ravine forests of Japan, Korea, northern China, eastern Siberia and Sakhalin, growing alongside Cercidiphyllum japonicum, Aesculus turbinata, and Pterocarya rhoifolia, at elevations of 700–2200 m, though sometimes lower in more northern latitudes, notably in Hokkaido.

<i>Ulmus macrocarpa</i> Species of tree

Ulmus macrocarpaHance, the large-fruited elm, is a deciduous tree or large shrub endemic to the Far East excluding Japan. It is notable for its tolerance of drought and extreme cold and is the predominant vegetation on the dunes of the Khorchin sandy lands in the Jilin province of north-eastern China, making a small tree at the base of the dunes, and a shrub at the top.

<i>Ulmus davidiana</i> Species of tree

Ulmus davidiana, also known as the David elm, or Father David elm, is a small deciduous tree widely distributed across China, Mongolia, Korea, Siberia, and Japan, where it is found in wetlands along streams at elevations of 2000–2300 m (6,500–7,500 ft). The tree was first described in 1873 from the hills north of Beijing, China.

Ulmus pseudopropinquaWang & Li, occasionally known in the United States as the Harbin spring elm, is a small deciduous tree found only in Heilongjiang, the northeasternmost province in China. The tree has not been studied comprehensively, and it has been speculated it may be a natural hybrid of Ulmus davidiana var. japonica and Ulmus macrocarpa.

<i>Ulmus</i> Urban Elm cultivar

Ulmus 'Urban' is an American hybrid elm cultivar selected from the progeny of a controlled crossing of the Siberian Elm Ulmus pumila with the Dutch clone '148' in 1958 by Toru Arisumi of the USDA at Columbus, Ohio. Clone '148' had been sent to the US from the Netherlands in 1952 by Johanna Went, leader of the elm research team at the Willie Commelin Scholten Phytopathology Laboratory in Baarn.

<i>Ulmus</i> Morton Elm cultivar

Ulmus 'Morton' is an elm cultivar cloned from a putative intraspecific hybrid planted at the Morton Arboretum in 1924, which itself originated as seed collected from a tree at the Arnold Arboretum in Massachusetts. Although this tree was originally identified as Ulmus crassifolia, it is now believed to have been a hybrid of the Japanese elm and Wilson's elm. Accolade has proven to be the most successful cultivar tested in the US National Elm Trial, averaging a survival rate of 92.5% overall.

The Japanese Elm cultivar Ulmus davidianavar.japonica'Discovery' is a cold-resistant selection from Canada, raised along with 'Freedom' in the 1980s by Dr Wilbert Ronald, of Jeffries Nurseries Ltd. and Rick Durrand of Shade Consulting Services, Portage la Prairie, Manitoba.

The Japanese Elm cultivar Ulmus davidianavar.japonica 'Freedom' is another cold-resistant selection from Canada, raised along with 'Discovery' in the 1980s by Dr Wilbert Ronald, of Jeffries Nurseries Ltd., and Rick Durrand of Shade Consulting Services, Portage la Prairie, Manitoba.

<i>Ulmus davidiana</i> var. <i>japonica</i> Jacan Elm cultivar

The Japanese Elm cultivar Ulmus davidianavar.japonica 'Jacan' is a cold-resistant selection from Canada. The tree was one of a group of second-generation japonica seedlings raised in the 1970s, originally for use in the prairie regions, by the Morden Research Station, Morden, Manitoba. It was first distributed in 1977, and was later among the Asiatic elms, some sourced from Canada, donated to the UK in 1980 by the London branch of Mitsui & Co.

The Japanese Elm cultivar Ulmus davidianavar.japonica 'Mitsui Centennial' is a cold-resistant selection raised at the Morden Experimental Station, Manitoba, Canada, in the 1970s, originally for use in the prairie regions. It was named to mark the centenary in 1980 of the London branch of Mitsui & Co., being one of a batch of Asiatic elms, some sourced from Canada, donated to the UK in that year by the company.

Ulmus davidianavar.japonica 'JFS-Bieberich' is a Japanese Elm cultivar that was raised by the Sunshine Nursery, Oklahoma, from seed collected in China by proprietor Steve Bieberich. Emerald Sunshine proved only moderately successful in the US National Elm Trial, averaging a survival rate of 70% overall.

<i>Ulmus davidiana</i> var. <i>japonica</i> Prospector Elm cultivar

The Japanese elm cultivar Ulmus davidianavar.japonica 'Prospector' was originally treated as a cultivar of Wilson's elm U. wilsonianaSchneid., a species sunk as Ulmus davidiana var. japonica by Fu. A U.S. National Arboretum introduction, it was selected in 1975 from a batch of 1965 seedlings in Delaware, Ohio, and released without patent restrictions in 1990. 'Prospector' proved moderately successful in the US National Elm Trial, averaging a survival rate of 76% overall.

<i>Ulmus</i> Patriot Elm cultivar

Ulmus 'Patriot' is a hybrid cultivar raised by the United States National Arboretum in 1980. Derived from a crossing of the American hybrid 'Urban' with the Wilson's Elm cultivar 'Prospector', 'Patriot' was released to commerce, free of patent restrictions, in 1993. Tested in the US National Elm Trial coordinated by Colorado State University, 'Patriot' averaged a survival rate of 85% after 10 years.

<i>Ulmus laciniata <span style="font-style:normal;">var.</span> nikkoensis</i> Variety of tree

Ulmus laciniata var. nikkoensisRehder, the Nikko elm, was discovered as a seedling near Lake Chūzenji, near Nikkō, Japan, and obtained by the Arnold Arboretum in 1905. The taxonomy of the tree remains a matter of contention, and has been considered possibly a hybrid of U. laciniata and U. davidiana var. japonica. However, in crossability experiments at the Arnold Arboretum in the 1970s, U. laciniata, a protogynous species, was found to be incompatible with U. davidiana var. japonica, which is protandrous.

The National Elm Trial was an American volunteer effort to evaluate a range of newly developed elm cultivars as replacements for elms destroyed by Dutch elm disease. The Colorado State University College of Agricultural Sciences coordinated the trial.

The Japanese Elm cultivar Ulmus davidianavar.japonica 'Reseda' is an American cultivar raised by the Wisconsin Alumni Research Foundation (WARF) as clone no. 43–8. 'Reseda' was grown from seed sent from Hokkaido, Japan, in the late 1950s. Although not released in its own right, it was destined to become the female parent of the highly successful hybrid cultivars 'New Horizon' and 'Rebona'.

Ulmus×mesocarpaM. Kim & S. Lee is a natural hybrid elm which is a cross of Ulmus macrocarpa with Japanese elm Ulmus davidiana var. japonica discovered on Seoraksan near the city of Sokcho on the eastern coast of South Korea. The tree is endemic to the provinces of Gangwon-do, Injegun, Bukmyeon, Yongdaeri, and Baekdamsa.

References

  1. 1 2 3 4 Lindquist, C. H. & Howe, J. A. G. (1979). Thomson Elm. Canadian Journal of Plant Science 59:1159
  2. Schroeder, W. (1994). Genetic improvement for prairie tree plantings. Journal of Arboriculture. 20(1), Jan. 1994.
  3. Burdekin, D.A.; Rushforth, K.D. (November 1996). "Elms resistant to Dutch elm disease" (PDF). Arboriculture Research Note. 2/96. Revised by J.F. Webber. Alice Holt Lodge, Farnham: Arboricultural Advisory & Information Service: 1–9. ISSN   1362-5128 . Retrieved 26 October 2017.
  4. Tree, bark, buds and leaves photographs of 'Thomson', worldplants.ca
  5. Heybroek, Hans M. (1981). "The Japanese elm species and their value for the Dutch elm breeding program" (PDF). Proceedings of the Dutch Elm Disease symposium and workshop, October 5–9, Winnipeg, Manitoba: 78–90.
  6. Photographs of 'Thomson' at Royal Botanical Gardens, Burlington, Ontario; U. davidiana var. japonica; worldplants.ca