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Origins
Scientists believe that the fungus that causes DED originally came from the Himalayas. It travelled to Europe from the Dutch East Indies in the late 1800’s. In the 1930’s, the disease spread to North America on
wooden crates made with infected elm wood.
A second introduction of the disease in North America occurred in 1945 starting in Sorel, Quebec. It destroyed over half the remaining elm trees in eastern Canada and the US. By 1976, only 34 million elm trees
were left.
New strains of the disease appeared in the 1960’s in England. Within 20 years, 17 million of the country’s 23 million elm trees were dead.
Moving West
The disease has now spread to Manitoba and Saskatchewan where there are approximately 500,000 elm trees in the cities. Three to five percent of the elms die each year
Winnipeg is spending C$2.5 million a year on sanitation and pruning. Having lost 40,000 trees in the last 20 years, the city’s elm population is now just 200,000.
More Than Just Beauty
Mature trees add to property values. The estimated value of a mature elm for insurance purposes is C$3,600 (US$2,500) per tree. With roughly 650,000 elms in cities in Canada, the elms are worth C$2.3 billion. The 7 million
urban trees in the US are worth US$17.5 billion.
Source: "The American elm and Dutch elm disease" M. Hubbes, Forestry Chronicle, March/April 1999. Vol. 75, No. 2,
p.265
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