The Hague
Out of a total population of elms approximately 16,000 trees are located along streets and canals and thousands more elms are found in parks and private property.
Close to the coast, the elm is one of the few trees capable of withstanding the salty see winds and still grow well in the harsh conditions of a city. On top of that, the elm has been a part of the city’s history for centuries and a distinctive tree in the city’s landscape.
Dutch elm disease in The Hague
The city started searching for a solution to Dutch Elm Disease in the 70’s. At that time the city was losing thousands of elms in their streets yearly, approximately 7% each year. This not only led to losses of old and valuable city elms, but also involved high costs for removal and replacement.
The DutchTrig® injection and sanitation program
From 1995 to 1997 the preventative DutchTrig® treatment was introduced and assessed to determine the effectiveness. The results of the treatments were very encouraging, showing a big decrease in Dutch Elm Disease prevalence in vaccinated trees. These positive results led to the development of a large scale injection scheme in 1998 by the City’s Park Service, selecting some 9,000 out of 30,000 trees to be injected each year.
Together with the injection scheme, the sanitation programme was reinforced. Elms in the city were checked for Dutch Elm Disease several times during the growing season, infected elms removed and lost elms replaced with more resistant elm clones.
Treatment results
As a result disease incidence in The Hague declined considerably, from the moment the large-scale DutchTrig® injection scheme was implemented.
Conclusion: a green and characteristic The Hague
The Hague aimed to reduce the loss of valuable city elms, through the sanitation and injection programme, and generating public interest for city trees. Because of its success the city continues the programme supported by arborists, the public and politicians, all enjoying a ‘green’ city and the conservation of the natural heritage of The Hague.
