Ulmus 'Christine Buisman'

Ulmus
'Christine Buisman' Amsteldijk, Amsterdam. Photo: Ronnie Nijboer, Bonte Hoek kwekerijen
Details
Cultivar	'Christine Buisman'
Origin	Netherlands

The elm cultivar 'Christine Buisman' was the first release of the Dutch elm breeding programme initiated in response to the less virulent form of Dutch elm disease (DED), Ophiostoma ulmi, which afflicted Europe's elms after the First World War.^[1] 'Christine Buisman' was selected as No. '24' from a lot of >300 seedlings, identified as Ulmus foliacea (syn. U. minor) but later considered to be Ulmus × hollandica by Melville ^[2], obtained from Spain (probably Madrid) in 1929.

To begin with, No. '24' showed no signs of DED after several artificial inoculations, but in later years minor symptoms were detected on both the motherplant and grafted descendants, but these were considered too insignificant to delay its release to commerce as Ulmus 'Christine Buisman' in 1936.

Description

The tree has an upright, oval habit generally considered unattractive owing to its irregular growth pattern.^[3]

Pests and diseases

Moderately resistant to Dutch elm disease (DED), but very prone to cankers caused by Coral Spot fungus Nectria cinnabarina as it lacked resistance mechanisms. It has been suggested that the tree may have a better field (rather than intrinsic) resistance to DED, which would better explain the survival of so many older trees in the Europe and the USA.

Cultivation

The tree had not been thoroughly evaluated in the field before its release. However, such was the clamour for a resistant tree in the The Netherlands, nurseries there raised and released large numbers, selling almost 10,000 per annum by the late 1930s. Once its shortcomings, which included poor resistance to sea winds, became apparent, commercial production soon ceased ^[4], although by this time it had already been exported to Italy and the USA ^[5] where it was planted as a street tree until the late 1950s. The tree can still be found in the Netherlands, notably in The Hague, and Heiloo, and in the UK at Brighton.

Notable trees

A large specimen planted in 1957 by Bernice Cronkhite in memory of Christine Buisman survives (2010) outside the Cronkhite Graduate Center, Harvard University, USA.^[6]. A particularly impressive plantation exists in the USA at Buffalo, along the McKinley Parkway its side streets.

Cultivars

• U. '297'. Dutch self-pollinated tree. Specimen planted at Preston Park, Brighton, in 1964; 19 m high, 43 cm d.b.h. in 2001. Other examples of the same can be found on waste land north of Patcham, Brighton.

Etymology

The tree is named for Christine Buisman, one of the original team of elm researchers at Wageningen which discovered the cause of Dutch elm disease in 1927.

Synonymy

• Ulmus 'Buisman': Plant Buyer's Guide, ed. 6. 285, 1958, without description.
• Ulmus × hollandica 'Christine Buisman': Melville, and various arboreta listings in USA and Europe.
• Ulmus procera 'Christine Buisman': Morton Arboretum Catalogue 2006.

Accessions

North America

• Arnold Arboretum. Acc. nos. 135-54, 273-46
• Bartlett Tree Experts. Acc. no. 1371
• Dawes Arboretum [2], Newark, Ohio. 3 trees, as U. carpinifolia 'Christine Buisman'. No acc. details available.
• Holden Arboretum. Acc. nos. 54-271, 55-446
• Longwood Gardens. Acc. no. 1967-0875
• Morton Arboretum (as Ulmus procera 'Christine Buisman'). Acc. no. 223-49, 30-2007 (graft).
• U S National Arboretum [3], Washington, D.C., USA. Acc. no. 76239.

Europe

• Brighton & Hove City Council, UK, NCCPG Elm Collection [4] (as Ulmus × hollandica 'Christine Buisman'). TROBI Champion: Palmeira Avenue, Hove, 16 m high, 33 cm d.b.h. in 2002 ^[7]. Three mature specimens grow at Carden Park, Hollingbury, Brighton.

References

1. ^ Heybroek, H. M. (1993). The Dutch Elm Breeding Program. In Sticklen & Sherald (Eds.)(1993). Dutch Elm Disease Research, Chapter 3. Springer Verlag, New York, USA
2. ^ Melville, R. (1978). On the discrimination of species in hybrid swarms with special reference to Ulmus and the nomenclature of U. minor (Mill.) and U. carpinifolia (Gled.). Taxon 27: 345-351
3. ^ Photograph of 'Christine Buisman' elm, [1].
4. ^ Heybroek, H. M. (1983). Resistant Elms for Europe. In Burdekin, D. A. (Ed.) Research on Dutch elm disease in Europe. For. Comm. Bull. 60. pp 108 - 113.
5. ^ Heybroek, H. M. (1957). Elm breeding in the Netherlands. Silvae Genetica, Vol. 6, No 3-4, pp 112-117, 1957.
6. ^ Anon. (1958). The Christine Buisman Elm. Radcliffe Quarterly Vol. XLI, February 1958, No. 1. p. 5. Harvard University, USA.
7. ^ Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 9781873580615.