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121-511: The villages of Hrabačov and Javorek are administrative parts of Jilemnice. The name was derived from the word jilm (' elm ') and from the adjective jilemná , related to some water course (meaning "water flowing between elms"). Jilemnice is located about 12 kilometres (7 mi) east of Semily and 34 km (21 mi) southeast of Liberec . It lies in a hilly landscape of the Giant Mountains Foothills . The highest points are

242-511: A vector for infection, it is much less effective than the large elm bark beetle, S. scolytus . H. rufipes can be a vector for the disease, but is inefficient compared to the other vectors. S. schevyrewi was found in 2003 in Colorado and Utah . Other reported DED vectors include Scolytus sulcifrons , S. pygmaeus , S. laevis , Pteleobius vittatus and Р. kraatzi . Other elm bark beetle species are also likely vectors. 'Field resistance'

363-474: A DED-ridden area. These have been tested and some have a very high level of resistance. At Noordplant Nursery new hybrids have been tested since 2013. Ten resistant American elm cultivars are now in commerce in North America. No cultivar is immune to DED; even highly resistant cultivars can become infected, particularly if already stressed by drought or other environmental conditions where the disease prevalence

484-629: A Renaissance building from the 16th century, built on the site of a former fortress. Between 1714 and 1895, it was gradually rebuilt into its present form. Today it houses the Giant Mountains Museum. The Church of Saint Lawrence is one of the most valuable buildings in Jilemnice. The church was built in the Baroque style in 1729–1735. Jilemnice is twinned with: Elm See Elms are deciduous and semi-deciduous trees comprising

605-639: A distinction in the human mind rather than a measured degree of genetic variation'. Eight species are endemic to North America and three to Europe, but the greatest diversity is in Asia with approximately two dozen species. The oldest fossils of Ulmus are leaves dating Paleocene , found across the Northern Hemisphere. The classification adopted in the List of elm species is largely based on that established by Brummitt. A large number of synonyms have accumulated over

726-524: A few branches, and had largely died out by 1940 owing to its susceptibility to viruses. In around 1967, a new, far more virulent , strain arrived in Britain, apparently via east coast ports on shipments of rock elm U. thomasii logs from Canada destined for the small-boat industry, confirmed in 1973 when another consignment was examined at Southampton Docks. This strain proved both highly contagious and lethal to European elms; more than 25 million trees died in

847-661: A few days. They are planted in sandy potting soil at a depth of 1 cm, and germinate in three weeks. Slow-germinating American elm will remain dormant until the second season. Seeds from autumn-flowering elms ripen in the fall and germinate in the spring. Since elms may hybridize within and between species, seed propagation entails a hybridisation risk. In unfavourable seasons, elm seeds are usually sterile. Elms outside their natural range, such as English elm U. minor 'Atinia' , and elms unable to pollinate because pollen sources are genetically identical, are sterile and are propagated by vegetative reproduction . Vegetative reproduction

968-430: A number of methods to control the epidemic, including sanitation , pruning , injecting trees with fungicide and replanting with DED-resistant American elm cultivars (see Ulmus americana cultivars ). The NPS combated the disease's local insect vector , the smaller European elm bark beetle ( Scolytus multistriatus ), by trapping and by spraying with insecticides . As a result, the population of American elms planted on

1089-552: A prevention program initiated in 1981. Alberta and British Columbia are the only provinces that are currently free of Dutch elm disease, although, in an isolated case, an elm tree in Wainwright, Alberta , was found diseased in June 1998 and was immediately destroyed. The presence of DED was monitored in this area during subsequent years but was not seen again. Today, Alberta has the largest number of elms unaffected by Dutch elm disease in

1210-663: A progressive manner throughout the tree, with further dieback of branches. Eventually, the roots die, starved of nutrients from the leaves. Often, not all the roots die: the roots of some species, especially the English elm (formerly Ulmus procera ), can repeatedly put up suckers, which flourish for approximately 15 years before dying off. 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. Barendina Gerarda Spierenburg compiled records of trees displaying symptoms from 1900 - 1905 onwards in

1331-468: A result, the population of American elms planted on the Mall and its surrounding areas has remained intact for more than 80 years. Elm wood is valued for its interlocking grain, and consequent resistance to splitting, with significant uses in wagon -wheel hubs, chair seats, and coffins . The bodies of Japanese Taiko drums are often cut from the wood of old elm trees, as the wood's resistance to splitting

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1452-537: A shipment of logs from the Netherlands destined for use as veneer in the Ohio furniture industry. Quarantine and sanitation procedures held most cases within 150 mi (240 km) of metropolitan New York City until 1941 when war demands began to curtail them. The disease spread from New England westward and southward, almost completely destroying the famous elms in the "Elm City" of New Haven, Connecticut , reaching

1573-467: A single variety that possessed of any significant resistance. The first, less aggressive strain of the disease fungus, Ophiostoma ulmi , arrived in Europe from Asia in 1910, and was accidentally introduced to North America in 1928. It was steadily weakened by viruses in Europe and had all but disappeared by the 1940s. However, the disease had a much greater and longer-lasting impact in North America, owing to

1694-532: A small number of wych elms U. glabra surviving in areas of high infectivity, prompting the Royal Botanic Garden Edinburgh to begin a programme of selecting trees, with a view to determining innate resistance (2009). The Garden is raising and distributing in Scotland seedlings derived from controlled crosses of rare survivors in these areas (2023). In 2001–2004, English elm U. minor 'Atinia'

1815-687: A source of antifungal genes. Early efforts in the USA involved the hybridization of the Siberian elm U. pumila with American red elm U. rubra to produce resistant trees. Resulting cultivars lacked the traditional shape and landscape value of the American elm; few were planted. In 2005, the National Elm Trial (USA) began a 10-year evaluation of 19 cultivars in plantings across the United States. The trees in

1936-480: A tree has unusual symbolic value or occupies a particularly important place in the landscape. Research to select resistant cultivars and varieties began in the Netherlands in 1928, followed by the United States in 1937 (see Ulmus americana cultivars ). Initial efforts in the Netherlands involved crossing varieties of U. minor and U. glabra , but later included the Himalayan or Kashmir elm U. wallichiana as

2057-512: A trend aided by fungicides . Lignasan BLP ( carbendazim phosphate ), introduced in the 1970s, was the first fungicide used to control Dutch elm disease. This had to be injected into the base of the tree using specialized equipment, and was never especially effective. It is still sold under the name "Elm Fungicide". Arbotect ( thiabendazole hypophosphite ) became available some years later, and it has been proven effective. Arbotect must be injected every two to three years to provide ongoing control;

2178-475: A wind speed of less than five metres per second. The largest concentration of mature elms in Scotland is in Edinburgh , where over 5,000 remained in 2009 from some 35,000 in 1976. The city council gives the overall number of elms as 15,000 (2016). Edinburgh's Leith Links and Meadows have some of the highest concentrations of mature elms among U.K. parks (2014). A policy of sanitary felling has kept losses in

2299-445: Is hermaphroditic , having apetalous perfect flowers which are wind-pollinated. Elm leaves are alternate, with simple, single- or, most commonly, doubly serrate margins, usually asymmetric at the base and acuminate at the apex . The fruit is a round wind-dispersed samara flushed with chlorophyll , facilitating photosynthesis before the leaves emerge. The samarae are very light, those of British elms numbering around 50,000 to

2420-599: Is a nationwide trial to assess strengths and weaknesses of the 19 leading cultivars raised in the US over a 10-year period; European cultivars have been excluded. Meanwhile, in Europe, American and European cultivars are being assessed in field trials started in 2000 by the UK charity Butterfly Conservation . The oldest American elm trees in New York City's Central Park were planted in the 1860s by Frederick Law Olmsted , making them among

2541-453: Is also resistant to decay when permanently wet, and hollowed trunks were widely used as water pipes during the medieval period in Europe. Elm was also used as piers in the construction of the original London Bridge , but this resistance to decay in water does not extend to ground contact. The Romans, and more recently the Italians, planted elms in vineyards as supports for vines. Lopped at 3 m,

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2662-480: Is also used to produce genetically identical elms (clones). Methods include the winter transplanting of root suckers ; taking hardwood cuttings from vigorous one-year-old shoots in late winter, taking root cuttings in early spring; taking softwood cuttings in early summer; grafting ; ground and air layering ; and micropropagation . A bottom heat of 18 °C and humid conditions are maintained for hard- and softwood cuttings. The transplanting of root suckers remains

2783-483: Is an umbrella term covering the various factors by which some elms avoid infection in the first place, rather than survive it. A clear example would be the European White Elm ( Ulmus laevis ) which, while having little or no genetic resistance to DED, synthesizes a triterpene , Alnulin, rendering the bark distasteful to the vector beetles, obliging them to look further afield for more suitable elms. Another would be

2904-569: Is being paid to trees as sources of energy. In Italy, the Istituto per la Protezione delle Piante is (2012) in the process of releasing to commerce very fast-growing elm cultivars, able to increase in height by more than 2 m (6 ft) per year. Elm bark , cut into strips and boiled, sustained much of the rural population of Norway during the great famine of 1812. The seeds are particularly nutritious, containing 45% crude protein, and less than 7% fibre by dry mass. Elm has been listed as one of

3025-586: Is believed to be in the city of Winnipeg , where close to 200,000 elms remain. The city spends $ 3 million annually to aggressively combat the disease using Dursban Turf and the Dutch Trig vaccine. Dutch elm disease has reached New Zealand . It was found in Napier where it was eradicated and was also found in the Auckland Region in 1989. The Ministry of Agriculture funded a national management programme but it

3146-401: Is caused by phytoplasmas that infect the phloem (inner bark) of the tree. Infection and death of the phloem effectively girdles the tree and stops the flow of water and nutrients. The disease affects both wild-growing and cultivated trees. Occasionally, cutting the infected tree before the disease completely establishes itself and cleanup and prompt disposal of infected matter has resulted in

3267-428: Is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles . Believed to be originally native to Asia , the disease was accidentally introduced into America , Europe , and New Zealand . In these regions it has devastated native populations of elms that did not have resistance to the disease. The name "Dutch elm disease" refers to its identification in 1921 and later in

3388-684: Is high. With the exception of 'Princeton', no trees have yet been grown to maturity; trees cannot be said to be mature until they have reached an age of 60 years. Notable cultivars include: In 2007, the Elm Recovery Project of the University of Guelph Arboretum in Ontario, Canada, reported that cuttings from healthy surviving old elms surveyed across Ontario had been grown to produce a bank of resistant trees, isolated for selective breeding of highly resistant cultivars. The University of Minnesota USA

3509-479: Is highly desired for nailing the skins to them, and a set of three or more is often cut from the same tree. The elm's wood bends well and distorts easily. The often long, straight trunks were favoured as a source of timber for keels in ship construction. Elm is also prized by bowyers ; of the ancient bows found in Europe, a large portion are elm. During the Middle Ages , elm was also used to make longbows if yew

3630-413: Is injected. Alamo is primarily recommended for treatment of oak wilt . Multistriatin is a pheromone produced by female elm bark beetles, which can be produced synthetically. It has potential in being used to trap male beetles, which carry the fungus. Because of the ban on the use of chemicals on street and park trees in the Netherlands, the University of Amsterdam developed a biological vaccine by

3751-495: Is invariably carried by the female parent. Some of these cultivars, notably those with the Siberian elm ( Ulmus pumila ) in their ancestry, lack the forms for which the iconic American elm and English elm were prized. Moreover, several exported to northwestern Europe have proven unsuited to the maritime climate conditions there, notably because of their intolerance of anoxic conditions resulting from ponding on poorly drained soils in winter. Dutch hybridizations invariably included

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3872-491: Is no longer monitored. Sapsucker woodpeckers have a great love of young elm trees. One of the earliest of ornamental elms was the ball-headed graft narvan elm, Ulmus minor 'Umbraculifera' , cultivated from time immemorial in Persia as a shade tree and widely planted in cities through much of south-west and central Asia. From the 18th century to the early 20th century, elms, whether species, hybrids, or cultivars , were among

3993-547: Is not favoured by the vector bark beetles. Thus it becomes colonized and infected only when no other elms are available, a rare situation in western Europe. Research in Spain has suggested that it may be the presence of a triterpene , alnulin , which makes the tree bark unattractive to the beetle species that spread the disease. This possibility, though, has not been conclusively proven. More recently, field elms Ulmus minor highly resistant to DED have been discovered in Spain, and form

4114-582: Is now hoped that the controlled crossing of the best seven of these (genetically and aesthetically) will produce Ulmus minor hybrids with effective 'field resistance' and market appeal. Similar results are beginning to emerge in trials on surviving field elms in Greece. Much of the work in the United Kingdom is by the Forestry Commission's research arm, which has had Dutch elm disease on its agenda since

4235-435: Is standard in both continents, its composition reflects the different Ophiostoma species, subspecies and hybrids endemic to the two continents. In Italy for example, two subspecies, americana and novo-ulmi , are present together with their hybrid, whereas in North America, ssp. novo-ulmi is unknown. The differences in method and inocula possibly explain why the American cultivar 'Princeton' , displaying high resistance in

4356-523: Is testing various elms, including a huge now-patented century-old survivor known as "The St. Croix Elm" , which is located in a Minneapolis-St. Paul, MN suburb (Afton) in the St. Croix River valley—a designated National Scenic Riverway. The slippery or red elm U. rubra is marginally less susceptible to Dutch elm disease than the other American species, but this quality seems to have been largely ignored in American research. No cultivars were ever selected, although

4477-522: 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 m high, are gone. The species still survives in hedgerows , as the roots are not killed and send up root sprouts ( "suckers" ). These suckers rarely reach more than 5 m tall before dying off from a new attack. However, established hedges kept low by clipping have remained apparently healthy throughout

4598-457: Is the unique example of the European white elm U. laevis , which has little innate resistance to DED, but is eschewed by the vector bark beetles and only rarely becomes infected. Recent research has indicated it is the presence of certain organic compounds, such as triterpenes and sterols , which serves to make the tree bark unattractive to the beetle species that spread the disease. In Europe

4719-458: Is thought to have originated in Asia. The two subspecies have now hybridized in Europe where their ranges have overlapped. The hypothesis that O. novo-ulmi arose from a hybrid of the original O. ulmi and another strain endemic to the Himalayas , Ophiostoma himal-ulmi , is now discredited. No sign indicates the current pandemic is waning, and no evidence has been found of a susceptibility of

4840-622: The Detroit area in 1950, the Chicago area by 1960, and Minneapolis by 1970. Of the estimated 77 million elms in North America in 1930, over 75% had been lost by 1989. The disease first appeared on the planted rows of American elm trees ( Ulmus americana ) on the National Mall in Washington, D.C. , during the 1950s and reached a peak in the 1970s. The United States National Park Service (NPS) used

4961-580: The Iliad , when the River Scamander , indignant at the sight of so many corpses in his water, overflows and threatens to drown Achilles, the latter grasps a branch of a great elm in an attempt to save himself ("ὁ δὲ πτελέην ἕλε χερσὶν εὐφυέα μεγάλην". The nymphs also planted elms on the tomb in the Thracian Chersonese of "great-hearted Protesilaus " ("μεγάθυμου Πρωτεσιλάου"), the first Greek to fall in

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5082-635: The Netherlands by Dutch phytopathologists Bea Schwarz and Christine Buisman , who both worked with professor Johanna Westerdijk . The disease affects species in the genera Ulmus and Zelkova , therefore it is not specific to the Dutch elm hybrid . Dutch elm disease (DED) is caused by ascomycete microfungi . Three species are now recognized: DED is spread in North America by three species of bark beetles (Family: Curculionidae , Subfamily: Scolytinae): In Europe, while S. multistriatus still acts as

5203-592: The Siberian elm is drought tolerant, in dry countries, new varieties of elm are often root-grafted onto this species. Dutch elm disease (DED) devastated elms throughout Europe and much of North America in the second half of the 20th century. It derives its name "Dutch" from the first description of the disease and its cause in the 1920s by Dutch botanists Bea Schwarz and Christina Johanna Buisman . Owing to its geographical isolation and effective quarantine enforcement, Australia has so far remained unaffected by DED, as have

5324-466: The Southern Hemisphere , notably Australasia . Some individual elms reached great size and age. However, in recent decades, most mature elms of European or North American origin have died from Dutch elm disease , caused by a microfungus dispersed by bark beetles . In response, disease-resistant cultivars have been developed, capable of restoring the elm to forestry and landscaping . The genus

5445-521: The Waldstein family . The regular ground plan of the historic centre indicates that the town was probably founded on a green field. Because of its secluded location, the town developed in a slower pace than other towns in fertile inland. However, Jilemnice's isolation protected the town against serious war damage for years. The town development was even more restricted from 1492, when the Waldstein family divided

5566-455: The pound (454 g ). (Very rarely anomalous samarae occur with more than two wings. ) All species are tolerant of a wide range of soils and pH levels but, with few exceptions, demand good drainage. The elm tree can grow to great height, the American elm in excess of 30 m (100 ft), often with a forked trunk creating a vase profile. There are about 30 to 40 species of Ulmus (elm);

5687-446: The vascular cambium , the other being the phloem ) delivers water and nutrients to the rest of the plant, these plugs prevent them from travelling up the trunk of the tree , starving the tree of water and nutrients, which eventually kills it. The first symptom of infection is usually an upper branch of the tree with leaves starting to wither and yellow in summer, months before the normal autumnal leaf shedding. This morbidity spreads in

5808-399: The 1920s. In 1994 a Research Information Note (no 252) was published, written by John Gibbs, Clive Brasier and Joan Webber, and in 2010 a Pathology Advisory Note, as well as throughout the period a stream of more academic papers: notable results have been the observation that the progress of the disease through Scotland has been quite slow, and that genetic engineering has been tried to improve

5929-467: The 1940s and 50s; the species last featured in hybridization as the female parent of 'Repura' and 'Revera' , both patented in 1993, although neither has yet appeared in commerce. In Italy , research was initiated at the Istituto per la Protezione delle Piante, Florence, to produce a range of disease-resistant trees adapted to the warmer Mediterranean climate, using a variety of Asiatic species crossed with

6050-557: 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 ). The losses are made up by the planting of disease-resistant cultivars . The largest concentration of mature elm trees remaining in England is in Brighton and Hove , East Sussex , where of

6171-467: The 19th century, while in northern Japan Japanese elm ( U. davidiana var. japonica ) was widely planted as a street tree. From about 1850 to 1920, the most prized small ornamental elm in parks and gardens was the 'Camperdown' elm ( U. glabra 'Camperdownii') , a contorted, weeping cultivar of the wych elm grafted on to a nonweeping elm trunk to give a wide, spreading, and weeping fountain shape in large garden spaces. In northern Europe, elms were among

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6292-651: The 30,000 elms in 1983 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. Empowered by the Dutch Elm Disease (Local Authorities) (Amendment) Order 1988, local authorities may order

6413-654: The 38 substances that are used to prepare Bach flower remedies , a kind of alternative medicine . Chinese elm ( Ulmus parvifolia ) is a popular choice for bonsai owing to its tolerance of severe pruning. In 1997, a European Union elm project was initiated, its aim to coordinate the conservation of all the elm genetic resources of the member states and, among other things, to assess their resistance to Dutch elm disease. Accordingly, over 300 clones were selected and propagated for testing. Many elm trees of various kinds have attained great size or otherwise become particularly noteworthy. Many artists have admired elms for

6534-622: The American elm ( U. americana ), resulting in the release of DED-resistant clones, notably the cultivars 'Valley Forge' and 'Jefferson' . Much work has also been done into the selection of disease-resistant Asiatic species and cultivars. In 1993, Mariam B. Sticklen and James L. Sherald reported the results of experiments funded by the US National Park Service and conducted at Michigan State University in East Lansing that were designed to apply genetic engineering techniques to

6655-454: The American elm have been successful; in a six-year experiment with the American elm in Denver, CO, annual Dutch elm disease losses declined significantly after the first year from 7 percent to between 0.4 and 0.6 percent; a greater and more rapid reduction in disease incidence than the accompanying tree sanitation and plant health care programs. Preventive treatment is usually justified only when

6776-634: The British countryside: parent trees are monitored for disease, while saplings were offered free to schools and community groups, who are asked to monitor their trees' progress on the Foundation's online elm map; in London, places with 'elm' in their name were offered a sapling – in an attempt to find out why some elms have survived while others succumbed to Dutch elm disease. Both these projects have been discontinued. The spread of DED to Scotland has focussed attention on

6897-715: The French Institut National de la Recherche Agronomique (INRA), which subjected the trees to 20 years of field trials in the Bois de Vincennes , Paris , before releasing them to commerce—-in 2002 and 2006, respectively. Asian species featured in the American DED research programs were the Siberian elm U. pumila , Japanese elm U. davidiana var. japonica , and the Chinese elm U. parvifolia , which gave rise to several dozen hybrid cultivars resistant not just to DED, but also to

7018-517: The Himalayan elm ( Ulmus wallichiana ) as a source of antifungal genes and have proven more tolerant of wet ground; they should also ultimately reach a greater size. However, the susceptibility of the cultivar 'Lobel', used as a control in Italian trials, to elm yellows has now (2014) raised a question mark over all the Dutch clones. Several highly resistant Ulmus cultivars have been released since 2000 by

7139-645: The Institute of Plant Protection in Florence, most commonly featuring crosses of the Dutch cultivar 'Plantijn' with the Siberian elm to produce resistant trees better adapted to the Mediterranean climate. Elms take many decades to grow to maturity, and as the introduction of these disease-resistant cultivars is relatively recent, their long-term performance and ultimate size and form cannot be predicted with certainty. The National Elm Trial in North America, begun in 2005,

7260-473: The Mall and its surrounding areas has remained intact for more than 80 years. DED reached eastern Canada during World War II, and spread to Ontario in 1967, Manitoba in 1975 and Saskatchewan in 1981. In Toronto , 80% of the elm trees have been lost to Dutch elm disease; many more fell victim in Ottawa , Montreal and other cities during the 1970s and 1980s. Quebec City still has about 21,000 elms, thanks to

7381-463: 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. In Britain, the disease was first identified in 1927 by T R Peace on English elm in Hertfordshire. This first strain was a relatively mild one, which killed only a small proportion of elms, more often just killing

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7502-487: The Netherlands and her publication 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 Bea Schwarz , a pioneering Dutch phytopathologist , and this discovery would lend the disease its name. Following this, in the 1920s and 30s Christine Buisman , working in

7623-422: The Netherlands in 1928 and continued, uninterrupted by World War II, until 1992. Similar programmes were initiated in North America (1937), Italy (1978) and Spain (1986). Research has followed two paths: In North America, careful selection has produced a number of trees resistant not only to DED, but also to the droughts and cold winters that occur on the continent. Research in the United States has concentrated on

7744-564: The Trojan War. These elms grew to be the tallest in the known world, but when their topmost branches saw far off the ruins of Troy, they immediately withered, so great still was the bitterness of the hero buried below, who had been loved by Laodamia and slain by Hector . The story is the subject of a poem by Antiphilus of Byzantium (first century AD) in the Palatine Anthology : Dutch elm disease Dutch elm disease ( DED )

7865-536: The US, has often succumbed to Dutch elm disease in Europe. Many attempts to breed disease-resistant cultivar hybrids have involved a genetic contribution from Asian elm species that are demonstrably resistant to this fungal disease. Much of the early work was undertaken in the Netherlands. The Dutch research programme began in 1928, and ended in 1992. During those 64 years, well over 1000 cultivars were raised and evaluated. Still in use are cultivars such as 'Groeneveld', 'Lobel', 'Dodoens', 'Clusius' and 'Plantijn', although

7986-459: The US, when Dutch elm disease spread away from the Atlantic coast, control focused on controlling the bark beetle by using insecticides such as DDT and dieldrin , which were sprayed heavily across all parts of elm trees, usually twice a year in the spring and again at a lower concentration in the summer. In its early years, it was generally thought by observers that pesticides did slow the spread of

8107-529: The United Kingdom alone, while France lost 97% of its elms. The disease spread rapidly northwards, reaching Scotland within 10 years. By 1990, very few mature elms were left in Britain or much of continental Europe. One of the most distinctive English countryside trees (See John Constable 's painting Salisbury Cathedral from the South-West ), the English elm U. minor 'Atinia' , is particularly susceptible as it

8228-458: The absence of the predators in their native lands. In Australia, introduced elm trees are sometimes used as food plants by the larvae of hepialid moths of the genus Aenetus . These burrow horizontally into the trunk then vertically down. Circa 2000, the Asian Zig-zag sawfly Aproceros leucopoda appeared in Europe and North America, although in England, its impact has been minimal and it

8349-664: The age of three, the infant goddess Artemis practised her newly acquired silver bow and arrows, made for her by Hephaestus and the Cyclopes , by shooting first at an elm, then at an oak, before turning her aim on a wild animal: The first reference in literature to elms occurs in the Iliad . When Eetion , father of Andromache , is killed by Achilles during the Trojan War , the mountain nymphs plant elms on his tomb ("περί δὲ πτελέας ἐφύτευσαν νύμφαι ὀρεστιάδες, κoῦραι Διὸς αἰγιόχoιo"). Also in

8470-451: The ambiguity in number results from difficulty in delineating species, owing to the ease of hybridization between them and the development of local seed-sterile vegetatively propagated microspecies in some areas, mainly in the Ulmus field elm ( Ulmus minor ) group. Oliver Rackham describes Ulmus as the most critical genus in the entire British flora, adding that 'species and varieties are

8591-451: The basis of a major breeding programme. Owing to their innate resistance to DED, Asiatic species have been crossed with European species, or with other Asiatic elms, to produce trees that are both highly resistant to disease and tolerant of native climates. After a number of false dawns in the 1970s, this approach has produced a range of reliable hybrid cultivars now commercially available in North America and Europe. Disease resistance

8712-428: The beetles, invade the xylem or vascular system. The tree responds by producing tyloses , effectively blocking the flow from roots to leaves. Woodland trees in North America are not quite as susceptible to the disease because they usually lack the root grafting of the urban elms and are somewhat more isolated from each other. In France, inoculation with the fungus of over 300 clones of the European species failed to find

8833-496: The city to an average of 1,000 a year (2009). Between 2013 and 2020 losses were below 1,000 a year. 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

8954-593: The countryside, the former in northern areas including Scandinavia and northern Britain , the latter further south. The hybrid between these two, Dutch elm ( U. × hollandica ) , occurs naturally and was also commonly planted. In much of England, the English elm later came to dominate the horticultural landscape. Most commonly planted in hedgerows, it sometimes occurred in densities over 1000/km . In south-eastern Australia and New Zealand, large numbers of English and Dutch elms, as well as other species and cultivars, were planted as ornamentals following their introduction in

9075-447: 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. Sanitary felling has also, to date, preserved most of the 250,000 elms on the Isle of Man , where average temperature and wind speed inhibit the activity of the beetles, which need a temperature of at least 20 degrees to fly and

9196-566: The development of DED-resistant strains of American elm trees. In 2007, A. E. Newhouse and F. Schrodt of the State University of New York College of Environmental Science and Forestry in Syracuse reported that young transgenic American elm trees had shown reduced DED symptoms and normal mycorrhizal colonization. In Europe, the European white elm ( U. laevis ) has received much attention. While this elm has little innate resistance to DED, it

9317-650: The disease across the United States but as early as 1947, concern was raised that many bird species were killed in large numbers by ingesting poisoned invertebrates. In areas sprayed during the 1950s, local people observed birds such as the American woodcock , American robin , white-breasted nuthatch , brown creeper and various Poecile species dying. Biologist Rachel Carson consequently argued for improved sanitation and against spraying elms, which she saw as having been more effective in areas with earlier and greater experience countering Dutch elm disease. Spraying against elm bark beetles declined very rapidly after 1962,

9438-421: The disease generally cannot be eradicated once a tree is infected. Arbotect is not effective on root graft infections from adjacent elm trees. It is more than 99.5% effective for three years from beetle infections, which is the primary mode of tree infection. Alamo ( propiconazole ) has become available more recently, though several university studies show it to be effective only for the current season in which it

9559-402: The early Dutch hybrid 'Plantyn' as a safeguard against any future mutation of the disease. Two trees with very high levels of resistance, 'San Zanobi' and 'Plinio' , were released in 2003. 'Arno' and 'Fiorente' were patented in 2006 and entered commerce in 2012. All four have the Siberian elm U. pumila as a parent, the source of disease-resistance and drought-tolerance genes. 'Morfeo'

9680-511: The ease and grace of their branching and foliage, and have painted them with sensitivity. Elms are a recurring element in the landscapes and studies of, for example, John Constable , Ferdinand Georg Waldmüller , Frederick Childe Hassam , Karel Klinkenberg , and George Inness . In Greek mythology, the nymph Ptelea (Πτελέα, Elm) was one of the eight hamadryads , nymphs of the forest and daughters of Oxylos and Hamadryas. In his Hymn to Artemis , poet Callimachus (third century BC) tells how, at

9801-422: The easiest most and common propagation method for European field elm and its hybrids. For specimen urban elms, grafting to wych-elm rootstock may be used to eliminate suckering or to ensure stronger root growth. The mutant-elm cultivars are usually grafted, the "weeping" elms 'Camperdown' and 'Horizontalis' at 2–3 m (7–10 ft), the dwarf cultivars 'Nana' and 'Jacqueline Hillier' at ground level. Since

9922-451: The elms' quick growth, twiggy lateral branches, light shade, and root suckering made them ideal trees for this purpose. The lopped branches were used for fodder and firewood. Ovid in his Amores characterizes the elm as "loving the vine": ulmus amat vitem, vitis non deserit ulmum (the elm loves the vine, the vine does not desert the elm), and the ancients spoke of the "marriage" between elm and vine . The mucilaginous inner bark of

10043-665: The estate into two parts. In the 15th and 16th centuries, the main economic activities were ore mining and linen production. During the Thirty Years' War , the town was burned down by the Swedish army and after the war, the town failed to follow up on the previous sources of livelihood. In 1701, both parts of the estate were acquired and merged by the Harrach noble family. Since then, Jilemnice began to prosper again. Harrachs' progressive economic policy led to raising of local linen industry to

10164-415: The extreme cold of Asian winters. Among the most widely planted of these, both in North America and in Europe, are 'Sapporo Autumn Gold' , 'New Horizon' and 'Rebona' . Some hybrid cultivars, such as 'Regal' and 'Pioneer' are the product of both Dutch and American research. Hybridization experiments using the slippery (or red) elm U. rubra resulted in the release of 'Coolshade' and 'Rosehill' in

10285-566: The few trees tolerant of saline deposits from sea spray, which can cause "salt-burning" and die-back. This tolerance made elms reliable both as shelterbelt trees exposed to sea wind, in particular along the coastlines of southern and western Britain and in the Low Countries, and as trees for coastal towns and cities. This belle époque lasted until the First World War , when the elm began its slide into horticultural decline. The impact of

10406-469: The fungal pathogen in late May when the tree's growth is at its annual peak. Clones raised for testing are grown to an age of 3 or 4 years. In Europe, the inoculum is introduced into the cambium by a knife wound. However this method, developed in the Netherlands, was considered too severe in America, where the principal disease vector is the bark beetle Scolytus multistriatus , a far less effective vector than

10527-538: The fungus to a disease of its own caused by d-factors : naturally occurring virus-like agents that severely debilitated the original O. ulmi and reduced its sporulation. Elm phloem necrosis (elm yellows) is a disease of elm trees that is spread by leafhoppers or by root grafts. This very aggressive disease, with no known cure, occurs in the Eastern United States , southern Ontario in Canada, and Europe. It

10648-651: The garden of the Tuileries in front of the l'Orangerie and another in the Place Saint-Gervais in front of l'hôtel de ville de Paris . Losses are now being made up with disease-resistant cultivars, especially the Dutch-French research elm 'Nanguen' ( Lutèce ) , named for the ancient Roman name for the city: Lutetia. DED was first reported in the United States in 1928, with the beetles believed to have arrived in

10769-767: The genus Ulmus in the family Ulmaceae . They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical - montane regions of North America and Eurasia, presently ranging southward in the Middle East to Lebanon and Israel, and across the Equator in the Far East into Indonesia. Elms are components of many kinds of natural forests . Moreover, during the 19th and early 20th centuries, many species and cultivars were also planted as ornamental street, garden, and park trees in Europe , North America, and parts of

10890-510: The greater susceptibility of the American elm, Ulmus americana , which masked the emergence of the second, far more virulent strain of the disease Ophiostoma novo-ulmi . It appeared in the United States sometime in the 1940s, and was originally believed to be a mutation of O. ulmi . Limited gene flow from O. ulmi to O. novo-ulmi was probably responsible for the creation of the North American subspecies O. novo-ulmi subsp. americana . It

11011-510: The hostilities on Germany , the origin of at least 40 cultivars, coincided with an outbreak of the early strain of DED, Ophiostoma ulmi . The devastation caused by the Second World War , and the demise in 1944 of the huge Späth nursery in Berlin , only accelerated the process. The outbreak of the new, three times more virulent, strain of DED Ophiostoma novo-ulmi in the late 1960s, brought

11132-440: The inability of the beetles to see elms which did not break the silhouette. 'Weeping' elms are often spared infection owing to the beetles' aversion to hanging upside-down while feeding. In an attempt to block the fungus from spreading farther, the tree reacts by plugging its own xylem tissue with gum and tyloses , bladder-like extensions of the xylem cell wall . As the xylem (one of the two types of vascular tissue produced by

11253-470: The larger beetle endemic to Europe, Scolytus scolytus , which is unknown in America. In the method devised by the USDA , the inoculum is introduced to the cambium via a 2 mm-diameter hole drilled through the bark in the lower third of the tree. This method was further refined by the University of Wisconsin team, which drilled holes in the branches to simulate natural infection by the bark beetles feeding in

11374-510: The last three centuries; their currently accepted names can be found in the list of Elm synonyms and accepted names . Botanists who study elms and argue over elm identification and classification are called "pteleologists", from the Greek πτελέα (elm). As part of the suborder urticalean rosids , they are distantly related to cannabis , mulberries , figs , hops , and nettles . Elm propagation methods vary according to elm type and location, and

11495-432: The late 1980s. Dutch Trig is nontoxic, consisting of a suspension in distilled water of spores of a strain of the fungus Verticillium albo-atrum that has lost much of its pathogenic capabilities, injected in the elm in spring. The strain is believed to have enough pathogenicity left to induce an immune response in the elm, protecting it against DED during one growing season. This is called induced resistance . Trials with

11616-660: The majority of the trees, although several are still lost each year. Younger American elms that have been planted in Central Park since the outbreak are of the DED-resistant 'Princeton' and 'Valley Forge' cultivars. Several rows of American elm trees that the National Park Service (NPS) first planted during the 1930s line much of the 1.9-mile-length (3 km) of the National Mall in Washington, DC. DED first appeared on

11737-408: The most widely planted ornamental trees in both Europe and North America. They were particularly popular as a street tree in avenue plantings in towns and cities, creating high-tunnelled effects. Their quick growth and variety of foliage and forms, their tolerance of air-pollution, and the comparatively rapid decomposition of their leaf litter in the fall were further advantages. In North America,

11858-602: The nearly 40 years since the onset of the disease in the United Kingdom. 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 ). Some 30,000 of the 100,000 mature trees in The Hague are elms, planted because of their tolerance of salty sea-winds. Since

11979-641: The oldest stands of American elms in the world. Along the Mall and Literary Walk four lines of American elms stretch over the walkway forming a cathedral-like covering. A part of New York City's urban ecology , the elms improve air and water quality, reduce erosion and flooding, and decrease air temperatures during warm days. While the stand is still vulnerable to DED, in the 1980s the Central Park Conservancy undertook aggressive countermeasures such as heavy pruning and removal of extensively diseased trees. These efforts have largely been successful in saving

12100-547: The pandemic, and a number may survive, or have regenerated, unrecognised. Enthusiasm for the newer clones often remains low owing to the poor performance of earlier, supposedly disease-resistant Dutch trees released in the 1960s and 1970s. In the Netherlands, sales of elm cultivars slumped from over 56,000 in 1989 to just 6,800 in 2004, whilst in the UK , only four of the new American and European releases were commercially available in 2008. Efforts to develop DED-resistant cultivars began in

12221-475: The plant's survival via stump sprouts. Most serious of the elm pests is the elm leaf beetle Xanthogaleruca luteola , which can decimate foliage, although rarely with fatal results. The beetle was accidentally introduced to North America from Europe. Another unwelcome immigrant to North America is the Japanese beetle Popillia japonica . In both instances, the beetles cause far more damage in North America owing to

12342-434: The plantsman's needs. Native species may be propagated by seed. In their natural setting, native species, such as wych elm and European white elm in central and northern Europe and field elm in southern Europe, set viable seed in "favourable" seasons. Optimal conditions occur after a late warm spring. After pollination, seeds of spring-flowering elms ripen and fall at the start of summer (June); they remain viable for only

12463-402: The provinces of Alberta and British Columbia in western Canada . DED is caused by a micro fungus transmitted by two species of Scolytus elm-bark beetles , which act as vectors . The disease affects all species of elms native to North America and Europe, but many Asiatic species have evolved antifungal genes and are resistant. Fungal spores, introduced into wounds in the tree caused by

12584-493: The resistance levels in these trees aren't high enough to confer good protection. The programme had three major successes: 'Columella' , 'Nanguen' Lutèce , and 'Wanoux' Vada , all found to have an extremely high resistance to the disease when inoculated with unnaturally large doses of the fungus. Only 'Columella' was released during the Dutch programme's lifetime—-in 1987. Patents for the Lutèce and Vada clones were purchased by

12705-593: The resistance of the English elm . In England the Conservation Foundation had been propagating, distributing and planting clones of surviving indigenous elms, including field elms (but not the highly susceptible English elm ), as part of a scheme to return elms to city and countryside. The Foundation was running two elm programmes: the 'Great British Elm Experiment' and 'Ulmus londinium', an elm programme for London – these use saplings cultivated through micropropagation from mature parent elms found growing in

12826-587: The slippery elm ( Ulmus rubra ) has long been used as a demulcent , and is still produced commercially for this purpose in the US with approval for sale as a nutritional supplement by the Food and Drug Administration . Elms also have a long history of cultivation for fodder , with the leafy branches cut to feed livestock . The practice continues today in the Himalaya, where it contributes to serious deforestation. As fossil fuel resources diminish, increasing attention

12947-548: The slopes of the Chmelnice hill at 592 m (1,942 ft) above sea level, and the peak of Bubeníkovy vrchy at 588 m (1,929 ft). The Jizerka River flows through the northern part of the municipal territory. The Jilemka Stream flows through the town into the Jizerka. The first written mention of Jilemnice is from 1350. Jilemnice was founded probably in the 1320s as an economic centre of an extensive Štěpanice estate owned by

13068-402: The species most commonly planted was the American elm ( U. americana ), which had unique properties that made it ideal for such use - rapid growth, adaptation to a broad range of climates and soils, strong wood, resistance to wind damage, and vase-like growth habit requiring minimal pruning . In Europe, the wych elm ( U. glabra ) and the field elm ( U. minor ) were the most widely planted in

13189-508: The testing of clones of surviving field elms for innate resistance has been carried out since the 1990s by national research institutes, with findings centrally assessed and published. The first results of this ongoing project suggest that in some countries a very small number of native field elm genotypes have comparatively high levels of tolerance to DED. In Spain, for example, of around 5,000 native elms evaluated to 2013, some 25 genotypes (0.5% of those tested) fall into this category; and it

13310-494: The town is the Czech branch of the Devro company, a manufacturer of plastic casings for food products. From the service sector, the most important employer is the local hospital. The I/14 road from Liberec to Trutnov passes through the town. Jilemnice is located on the railway line Jablonec nad Jizerou – Martinice v Krkonoších . The main landmark of the town is Jilemnice Castle. It is

13431-452: The tree to its nadir. Since around 1990, the elm has enjoyed a renaissance through the successful development in North America and Europe of cultivars highly resistant to DED. Consequently, the total number of named cultivars, ancient and modern, now exceeds 300, although many of the older clones, possibly over 120, have been lost to cultivation. Some of the latter, however, were by today's standards inadequately described or illustrated before

13552-786: The tree was used in hybridization experiments (see above). In 1993, Mariam B. Sticklen and James L. Sherald reported the results of NPS-funded experiments conducted at Michigan State University in East Lansing that were designed to apply genetic engineering techniques to the development of DED-resistant strains of American elm trees. In 2007, AE Newhouse and F Schrodt of the State University of New York College of Environmental Science and Forestry in Syracuse reported that young transgenic American elm trees had shown reduced DED symptoms and normal mycorrhizal colonization. By 2013, researchers in both New York State and North Carolina were conducting field trials of genetically engineered DED-resistant American elms. Among European species, there

13673-406: The trees during the 1950s and reached a peak in the 1970s. The NPS used a number of methods to control the epidemic , including sanitation , pruning , injecting trees with fungicide , and replanting with DED-resistant cultivars. The NPS combated the disease's local insect vector , the smaller European elm bark beetle ( Scolytus multistriatus ), by trapping and by spraying with insecticides . As

13794-646: The trial were exclusively American developments; no European cultivars were included. Based on the trial's final ratings, the preferred cultivars of the American elm ( Ulmus americana ) are ‘New Harmony’ and ‘Princeton’. The preferred cultivars of Asian elms are the Morton Arboretum introductions and ‘New Horizon’. Recent research in Sweden has established that early-flushing clones are less susceptible to DED owing to an asynchrony between DED susceptibility and infection. Elms are tested for resistance by inoculation with

13915-433: The twig crotches, but results from this method were found to exaggerate the genetic resistance of the host. Consequently, tests were conducted on specimens in a controlled environment, either in greenhouses or customized plant chambers, facilitating more accurate evaluation of both internal and external symptoms of disease. Another variable is the composition of the inoculum; while an inoculum strength of 10 spores /  ml

14036-490: The world level. During the first half of the 19th century, the linen industry gradually declined. In 1873, the Textile Industrial School was founded. Jilemnice continued to develop in the interwar period and became a tourist resort, but the war had a negative impact on the economy and tourism. After the war, the town's economy shifted to the engineering and food industries. The largest industrial employer based in

14157-492: The world. The provinces of Alberta, Manitoba, and Saskatchewan all prohibit the pruning of elm trees during the middle of the year (taking effect in April, and lasting through the end of September, July, and August respectively), which they deem to be the most active time of year for bark beetles. It is also illegal to use, store, sell, or transport elm firewood. The largest surviving urban forest of elm trees in North America

14278-686: Was cancelled to allow more funds to be available for pests of a higher priority. A major outbreak occurred in New Zealand in July 2013, particularly at the site of Kingseat Hospital , south of Auckland . Auckland has 20,000 elms. The first attempts to control Dutch elm disease consisted of pruning trees to remove and burn diseased timber . While this method was effective in New York State and adjacent areas, its cost made it uneconomical except in large cities where elms were considered valuable attractions. In

14399-471: Was first recognized in Britain in the early 1970s, believed to have been introduced via a cargo of Canadian rock elm destined for the boatbuilding industry, and rapidly eradicated most of the mature elms from western Europe. A second subspecies, O. novo-ulmi subsp. novo-ulmi , caused similar devastation in Eastern Europe and Central This subspecies, which was introduced to North America, and like O. ulmi ,

14520-583: Was released in 2011; it arose from a crossing of the Dutch hybrid clone '405' (female parent) and the Chenmou Elm , the latter a small tree from the provinces of Anhui and Jiangsu in eastern China, The '405' clone is a crossing of an English U. × hollandica and a French U. minor . In the Netherlands a new program has been initiated. From the old proving grounds of the Dorschkamp Research Institute, 10 fourth-generation hybrids survive in

14641-589: Was unavailable. The first written references to elm occur in the Linear B lists of military equipment at Knossos in the Mycenaean period . Several of the chariots are of elm (" πτε-ρε-ϝα ", pte-re-wa ), and the lists twice mention wheels of elmwood. Hesiod says that ploughs in Ancient Greece were also made partly of elm. The density of elm wood varies between species, but averages around 560 kg/m . Elm wood

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