THE Dutch elm disease (DED) season is once again upon us.
Diseased American elms are starting to show up. There has been a serious increase in the numbers of elms infected with the disease recently. Last year, more than 4,000 elms were removed. According to the City of Winnipeg forester, Martha Barwinsky, much of this increase in Winnipeg is a result of the illegal storage of elm firewood on private properties.
More than 150 firewood notices that were sent out were apparently ignored by property owners.
On streets where many elms have been removed, there are a number of nearby locations where elm firewood has been stored. The city is in a never-ending process of trying to get property owners to comply with the Dutch Elm Disease Act's regulations. There are legal ramifications for not complying with these regulations.
The city usually marks stored elmwood with a special red crayon. If you are not sure that the pieces of cut logs you have are elm, call the city and someone on the DED crew will examine the wood and let you know.
Elmwood, including the branches that are stored as firewood or simply cut logs, attract the native elm bark beetle to bore into the bark and wood. Why is stored wood a problem? The beetles breed in stressed elmwood whether it is on the tree or in a fire wood pile in someone's back yard.
If there is Dutch elm disease fungus in that wood, the female beetle's new brood of young borers can spread the disease to healthy elms when they emerge in the spring to feed. They breed in stressed trees but they feed on healthy trees.
Already there is an alarming increase in DED this year and it appears that the incidence of disease will be worse than last year.
More information about the city's Dutch elm disease control program can be found on the website http://www.winnipeg.ca/publicworks/Forestry/forestry.asp
American elms can be preventively injected with an approved fungicide while they are healthy, which will provide at least two years of protection from the disease. Contact the author for more information if you are interested.
Michael Allen is a consulting urban forester and certified I.S.A. arborist and owner of Viburnum Tree Experts. He makes house and garden visits to assess tree and shrub problems. He can be contacted by calling 831-6503 or by email at viburnumtrees@shaw.ca
