Editing Dutch elm disease (section)

===Europe===
Dutch elm disease was first noticed in continental Europe in 1910, and spread slowly and eventually extended to all other countries except Greece and Finland.<ref>Clouston, B., Stansfield, K., eds., ''After the Elm'' (London, 1979)</ref> [[Barendina Gerarda Spierenburg]] compiled records of trees displaying symptoms from 1900 - 1905 onwards in the Netherlands and her publication<ref name="Spierenburg1921">{{cite journal |last1=Spierenburg |first1=Barendina |title=Een onbekende ziekte in de iepen (An unknown disease in elms) |journal=European Journal of Plant Pathology |date=1921 |volume=27 |issue=5}}</ref> of this information in 1921 was one part of the start of extensive research and practical measures to try to halt the disease. In addition the fungus that caused the disease was isolated in 1921 in The Netherlands by [[Marie Beatrice Schol-Schwarz|Bea Schwarz]], a pioneering Dutch [[phytopathologist]], and this discovery would lend the disease its name.<ref>{{cite book |first1=Francis W. |last1=Holmes |first2=H.M. |last2=Heybroek |title=Dutch elm disease: the early papers : selected works of seven Dutch women phytopathologists |url=https://books.google.com/books?id=6fcgGd_KjjQC |year=1990 |publisher=APS Press |isbn=978-0-89054-110-4 }}</ref> Following this, in the 1920s and 30s [[Christine Buisman]], working in the Netherlands and USA, identified the sexual stage of the fungal pathogen and also developed methods for experimental infections of elm seedlings that led to selection of resistant trees.<ref name=Heybroek>Heybroek, H. M. and Nijboer, R. (2013). ''Christine Johanna Buisman in Italy''. p. 4–6. Private publication, Netherlands.</ref>

In Britain, the disease was first identified in 1927 by T R Peace on English elm in Hertfordshire.<ref name=Harris>Harris, E. (2017). The European White Elm, Ulmus laevis Pall. ''Quarterly Journal of Forestry'', Vol. 111, No. 4, October 2017. &nbsp;p.263. Royal Forestry Society.</ref> This first strain was a relatively mild one, which killed only a small proportion of elms, more often just killing a few branches, and had largely died out by 1940 owing to its susceptibility to viruses.

[[File:SalisburyCathedral.jpg|left|thumb|''[[Salisbury Cathedral from Lower Marsh Close]]'', 1820, Andrew W. Mellon Collection, National Gallery of Art, Washington, D.C.]]In around 1967, a new, far more [[virulent]], strain arrived in Britain, apparently via east coast ports on shipments of rock elm [[Ulmus thomasii|''U. thomasii'']] logs from Canada destined for the small-boat industry, confirmed in 1973 when another consignment was examined at Southampton Docks.<ref name=Harris/> This strain proved both highly contagious and lethal to European elms; more than 25 million trees died in the United Kingdom alone, while France lost 97% of its elms.<ref>{{cite web|archive-url=https://web.archive.org/web/20061125162935/http://www.international.inra.fr/research/some_examples/lutece_r_a_resistant_variety_brings_elms_back_to_paris|archive-date=25 November 2006|url=http://www.international.inra.fr/research/some_examples/lutece_r_a_resistant_variety_brings_elms_back_to_paris|title=Lutèce®, a resistant variety brings elms back to Paris|date=15 April 2005|work=All The News|location=[[Nantes]], France|publisher=[[Institut national de la recherche agronomique]] (INRA)}}</ref> The disease spread rapidly northwards, reaching Scotland within 10 years.<ref name=Harris/>

By 1990, very few mature elms were left in Britain or much of continental Europe. One of the most distinctive [[England|English]] countryside trees (See [[John Constable]]'s painting ''[[Salisbury Cathedral from Lower Marsh Close]]''), the English elm [[Ulmus minor 'Atinia'|''U. minor'' 'Atinia']], is particularly susceptible as it is the elm most favoured by the Scolytus beetles. Thirty years after the outbreak of the [[epidemic]], nearly all these trees, which often grew to more than 45&nbsp;m high, are gone. The species still survives in [[hedgerow]]s, as the roots are not killed and send up root sprouts ([[Basal shoot|"suckers"]]). These suckers rarely reach more than 5&nbsp;m tall before dying off from a new attack. However, established hedges kept low by clipping have remained apparently healthy throughout the nearly 40 years since the onset of the disease in the United Kingdom.
[[File:DED control notice.jpg|left|150px|thumb|Sign on A27, Brighton]]
The largest concentrations of mature elms in Europe are now in [[Amsterdam]] and [[The Hague]]. In 2005, Amsterdam was declared the "Elm City of Europe": the city's streets and canals are lined with at least 75,000 elms, including several generations of research-elms (see below: [[#Resistant trees|Resistant trees]]).<ref>{{cite web |title=Amsterdam, City of Trees |date=18 May 2011 |publisher=DutchAmsterdam |url=http://dutchamsterdam.nl/127-amsterdam-trees}}</ref><ref>[http://www.amsterdamsebomen.nl/index.php?option=com_content&task=view&id=83 Amsterdamse Bomem] {{webarchive|url=https://web.archive.org/web/20110724143734/http://www.amsterdamsebomen.nl/index.php?option=com_content&task=view&id=83 |date=2011-07-24 }}</ref> Some 30,000 of the 100,000 mature trees in [[The Hague]] are elms, planted because of their tolerance of salty sea-winds. Since the 1990s, a programme of antifungal injections of the most prominent 10,000 elms, and of sanitation felling, has reduced annual elm losses in The Hague from 7% to less than 1% (see below: [[#Preventive treatment|Preventive treatment]]). The losses are made up by the planting of disease-resistant [[cultivars]].<ref>{{cite web|title=The City and its elm population |work=The Hague in the Netherlands |publisher=DutchTrig® |url=http://dutchtrig.com/the_netherlands/the_hague.html |url-status=dead |archive-url=https://web.archive.org/web/20131029185155/http://dutchtrig.com/the_netherlands/the_hague.html |archive-date=2013-10-29 }}</ref> The largest concentration of mature elm trees remaining in England is in [[Brighton and Hove]], [[East Sussex]], where of the 30,000 elms in 1983<ref>''Research on Dutch Elm Disease in Europe'', ed. D. A. Burdekin (London, 1983)</ref> 15,000 still stand (2005 figures), several of which are estimated to be over 400 years old. Their survival is owing to the isolation of the area, between the [[English Channel]] and the [[South Downs]], and the assiduous efforts of local authorities to identify and remove infected sections of trees immediately when they show symptoms of the disease.<ref>[http://www.brighton-hove.gov.uk/index.cfm?request=c1000983 Brighton and Hove Council page on the city's elm collection] {{webarchive|url=https://web.archive.org/web/20110614054732/http://www.brighton-hove.gov.uk/index.cfm?request=c1000983 |date=2011-06-14 }} (viewed 2 June 2010)</ref> Empowered by the Dutch Elm Disease (Local Authorities) (Amendment) Order 1988,<ref>{{cite web|title=Dutch Elm Disease (DED) |year=2009 |work=Environment and Planning: Land and premises: Conservation: Trees & landscapes |publisher=Lewes District Council |url=http://www.lewes.gov.uk/environment/5954.asp |url-status=dead |archive-url=https://web.archive.org/web/20090705235243/http://www.lewes.gov.uk/environment/5954.asp |archive-date=5 July 2009 }}</ref> local authorities may order the destruction of any infected trees or timber, although in practice they usually do it themselves, successfully reducing the numbers of elm bark beetle ''Scolytus'' spp.<ref>{{cite web |author=Gupta, Tanya |title=How Brighton beat Dutch Elm menace  |date=11 November 2005 |work=BBC News, South East |url=http://news.bbc.co.uk/1/hi/england/4403620.stm}}</ref> Sanitary felling has also, to date, preserved most of the 250,000 elms on the [[Isle of Man]],<ref>[http://www.geocomputation.org/2009/PDF/Mitchell_et_al.pdf Isle of Man elms, geocomputation.org]</ref> where average temperature and wind speed inhibit the activity of the beetles, which need a temperature of at least 20 degrees to fly and a wind speed of less than five metres per second.<ref name=coleman2016>{{cite journal|first1=M.|last1=Coleman|first2=S.W.|last2=A'Hara|first3=P.R.|last3=Tomlinson|first4=P.J.|last4=Davey|date=2016|journal=New Journal of Botany|title=Elm clone identification and the conundrum of the slow spread of Dutch Elm Disease on the Isle of Man|volume=6|issue=2–3|pages=79–89|doi=10.1080/20423489.2016.1271612|bibcode=2016NJBot...6...79C |s2cid=90001207}}</ref><ref>[http://prolandscapermagazine.com/climate-pins-down-dreaded-tree-disease/ prolandscapermagazine.com 24 February 2017]</ref> [[File:Diseased elm, Bruntsfield Links, Edinburgh.jpg|thumb|Felling a diseased elm, Edinburgh, November 2011]] The largest concentration of mature elms in Scotland is in [[Edinburgh]], where over 5,000 remained in 2009 from some 35,000 in 1976.<ref>Coleman, Max, ed., ''Wych Elm'' (Edinburgh 2009)</ref> The city council gives the overall number of elms as 15,000 (2016).<ref>edinburgh.gov.uk/info/20064/parks_and_green_spaces/256/trees_and_woodlands</ref> Edinburgh's [[Leith Links]] and [[The Meadows (park)|Meadows]] have some of the highest concentrations of mature elms among U.K. parks (2014). A policy of sanitary felling has kept losses in the city to an average of 1,000 a year (2009).<ref>{{cite book |first=Max |last=Coleman |title=Wych Elm |year=2009 |publisher=Royal Botanic Gardens Edinburgh |isbn=978-1-906129-21-7 |page=47 }}</ref> Between 2013 and 2020 losses were below 1,000 a year.<ref name = "EdinDED">[https://treecare.org.uk/2101/dutch-elm-disease-management-in-edinburgh/ 'Dutch elm disease management in Edinburgh' (2021); treecare.org.uk]</ref> Elm was the most common tree in Paris from the 17th century; before the 1970s there were some 30,000 ''ormes parisiens''. Today, only 1,000 mature elms survive in the city, including examples in the large avenues (Avenue d'Italie, Avenue de Choisy, Boulevard Lefebvre, Boulevard de Grenelle, Boulevard Garibaldi) and two very old specimens, one in the garden of the [[Tuileries]] in front of the [[Orangery|l'Orangerie]] and another in the [[Place Saint-Gervais]] in front of [[Hôtel de Ville, Paris|l'hôtel de ville de Paris]]. Losses are now being made up with disease-resistant cultivars, especially the Dutch-French research elm [[Ulmus 'Nanguen'|'Nanguen' ({{tdes|Lutèce|caps}})]], named for the ancient Roman name for the city: Lutetia.<ref>[http://www.international.inra.fr/research/some_examples/lutece_r_a_resistant_variety_brings_elms_back_to_paris Ulmus 'Nanguen' www.foretpriveefrancaise.com]</ref><ref>[http://www.foretpriveefrancaise.com/data/info/127219-P.pdf PDF] {{Webarchive|url=https://web.archive.org/web/20150924014610/http://www.foretpriveefrancaise.com/data/info/127219-P.pdf |date=24 September 2015 }}</ref>