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Return of the elm to the tree heritage, source of biodiversity

Posted on: 06/04/2022

The elm, a major component of our landscapes, has been devastated by the graphiosis disease since 1973. 30 years of research and experimentation have led to the selection of resistant varieties, published by SAPHO: Ulmus RESISTA® 'Sapporo Gold', Ulmus minor VADA® 'Wanoux', Ulmus Lutece® 'Nanguen

Thus, whether in historical heritage sites, such as the emblematic Tuileries Garden in Paris, or in natural preservation sites, such as the Marais Poitevin nature park, thanks to these resistant varieties, the elm is regaining its place in the landscape. This also brings new perspectives for the safeguard of a specific butterfly species, the White-letter hairstreak.

The elm, a major component of the landscape, devastated by graphiosis

Wikimedia - Par Rasbak — Travail personnel, CC BY-SA 3.0, 

Until the mid-70's, the elm was a major component of the French and European landscapes: tree in the center of the village, place of justice, tree of alignment, boulevard, mail, park, bocage. Its uses were diverse: ornamental but also, supply of firewood, fodder for cattle, cabinet making and carpentry.

The quality of its wood, water resistant, made it a material very much used for the paddle wheels of the water mills, the pilotis (piles of Venice), the wood of sailor and hubs of carts...

Following the development of the graphiosis disease throughout Europe, (*) the elm in the wild, with very few exceptions (some isolated trees), is permanently reduced to the state of shrub, resulting from the shoots and suckers of dead trees.

Resistant elm varieties after 30 years of research and experimentation

Selections of resistant elm are available to meet all uses thanks to the research work undertaken by INRAE in Nancy (Jean Pinon's work) in collaboration with Alterra -NL (Hans Heybroek) and INRAE in Angers (Alain Cadic) with the support of the City of Paris (monitoring of plantations in the Bois de Vincennes for 30 years) and SAPHO for development.

For hedgerows

Ulmus RESISTA® 'Sapporo Gold'

See the page RESISTA® 'Sapporo Gold'

Excellent trees in row

Ulmus minor VADA® 'Wanoux'

see the page VADA® 'Wanoux'

Mixed use: hedgerows, forests and woods, avenues

Ulmus LUTECE® 'Nanguen'

see the page LUTECE® 'Nanguen'

The selection criteria were: growth, resistance to diseases and adversities, adaptation to the environment, and suitability for cuttings.

Without pretending to replace all the disappeared adult trees, these varieties make it possible to plant new elms which can grow while remaining healthy.

Reconstitution of the tree heritage

To this day, more than 315,000 elms of the VADA® and LUTECE® varieties have been planted in France and abroad (mainly in the Netherlands and Great Britain). We are happy that these varieties participate in the reconstitution of the tree heritage in historical cultural sites as well as in natural heritage. Here are 2 examples.

The great alley of the Tuileries has recovered its border of elms, which had been cut down during the revolution

In early 2021, 92 elm trees - Ulmus minor VADA® 'Wanoux' - were planted on either side of the huge allée" of the Tuileries garden, recreating the layout of the garden as imagined by André Le Nôtre in his original version.

16 million walkers a year will be able to enjoy this new, more wooded atmosphere. This was made possible thanks to the 2020 edition of the "Tous Mécènes" operation.

Read the article in Le Parisien 29/01/2021

Resistant elms to renew the pollarded trees of our countryside

In the Parc naturel of the Marais Poitevin, most ash trees are between one and two centuries old and their renewal deserves to be anticipated. Moreover, a parasitic fungus of ash trees, Chalara fraxinea, causing Chalarosis, the ash wilt disease, is spreading rapidly in France. The owners are therefore called upon to participate in the replanting program launched by the Regional Nature Park.

The LUTECE® 'Nanguen' elm is one of the trees recommended in the guide of the Natural Park of the Marais Poitevin for various contexts: in row, in grove, in hedge or in isolated tree with a conduct: in pollard, in vines, in high jet or in free port.

Download the booklet "Which tree plant..." (french)

Préservation de la biodiversité animale

La Thècle de l’Orme, un papillon en voie d’extinction pourrait retrouver son habitat grâce à l’Umus Lutèce® ’Nanguen'

Avant 1970, la Thècle de l'orme (Satyrium w-album) était un papillon commun et répandu dans le sud de la Grande-Bretagne, mais il a toujours été considéré comme insaisissable, car il passe presque toute sa vie au sommet des ormes. Suite au développement de la graphiose, ce papillon, maintenant sur la liste rouge de l'UICN comme " en danger imminent d'extinction ".

La branche Hampshire & Isle of Wight de Butterfly Conservation (BC) a initié des essais de cultivars et d'espèces d'ormes résistants afin d’évaluer leur potentiel en tant que plantes hôtes.  Ce rapport, initialement publié en 2010, a été considérablement révisé à la lumière du fiasco de 'Princeton'. Princeton, un cultivar d'orme américain, a été largement promu au Royaume-Uni sans avoir été testé pour sa résistance par la méthode européenne d'inoculation. Cette méthode est beaucoup plus invasive, en raison de l'efficacité vectorielle beaucoup plus grande du scolyte de l'orme, Scolytus scolytus, qui n'existe pas aux États-Unis. La perte de nombreux ormes 'Princeton' à cause de la graphiose a obligé à reléguer d'autres cultivars américains jusqu'à ce qu'ils fassent leurs preuves ici.

En 2015, on a découvert que la thècle de l’orme se reproduisait sur les cultivars LUTECE® et 'Sapporo Autumn Gold'. La découverte du papillon sur LUTECE est particulièrement significative car l'arbre a une périodicité très différente de celle de son hôte indigène réputé favori, l'orme de Virginie, ce qui suggère que l'insecte possède une adaptabilité considérable qui pourrait le voir se reproduire sur tous les cultivars à haute résistance présentés dans ce rapport.

NB : La Thècle de l’Orme fait partie des espèces protégées en Ile de France depuis 1993.

Download the report

(*) The eradicating effects of Dutch elm disease

Dutch elm disease is a disease caused by a microscopic fungus that infects the vessels of the tree and causes its death. It is transmitted by a beetle, the Hylurgopinus rufipes. European species of Ulmus are particularly susceptible. Driven by the wood trade, a first wave arrived in Europe in the 1920's, but a second and more virulent strain was devastating from 1973 onwards.

The British have estimated that 25 million adult trees have been lost. Some French departments have lost more than 99% of their elm trees according to the national forest inventory.

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This article was written with information and photos provided by Jean Pinon, Honorary Research Director, INRAE de Nancy-Champenoux 

Posted in: Nachrichten zu Sapho-Sorten

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