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To identify an elm tree, the bark will have reddish and cream coloured ridges in the cross section. (Submitted photo/Saskatchewan Ministry of the Environment)
Protecting environment

People asked not to prune elm trees to prevent Dutch elm disease

Apr 1, 2021 | 6:05 PM

Residents across Saskatchewan are asked not to prune their elm trees starting April 1 in an effort to prevent the spread of Dutch elm disease (DED) in the province. They can return to pruning again in September.

Dutch elm disease is a fungal disease that kills elm trees. The Saskatchewan Ministry of the Environment announced the annual ban as this is the time of year the elm bark beetles that spread DED are most active. Any fresh cuts from trimming elm trees can attract these insects, which increases the risk of infecting more elm trees.

“By minimizing the amount of tree wounding during the time when beetles are active you can minimize the risk of Dutch elm disease spreading,” Saskatchewan Ministry of the Environment forest entomologist and pathologist Rory McIntosh said.

The leaves of an elm tree have an oval shape and what are described as toothed edges. (Submitted photo/Saskatchewan Ministry of the Environment)

Anyone noticing an elm tree exhibiting signs of DED – wilting, yellowing leaves on one or a number of branches near the upper portion of the tree, usually starting in late June, must report it to their local municipality.

People can remove a DED-infected elm tree at any time of the year as long as it is disposed of properly at the landfill. In this case, McIntosh said, the whole tree has to be removed and the stump properly ground down.

The province notes it is illegal to use, transport, store or sell elm firewood. Transporting the elm wood can spread DED, along with other insects and diseases.

“One of the problems with the disease spreading so quickly across the country is people throwing loads of firewood on the back of their truck and driving it 500 or 600 kilometres,” McIntosh said. “Then, they will store it at their house or cabin and the beetles will come out and overwinter or feed in those trees. Then, they [these insects] will kill elm trees in and around that new area.”

A photograph of a DED infected tree. (Submitted photo/Saskatchewan Ministry of the Environment)

Looking at the North West Saskatchewan region, McIntosh said he is aware Lloydminster and Battleford both have elm trees in the municipalities. There are also shelter belt elm trees throughout Saskatchewan.

One of the closest areas or the furthest west, where Dutch elm disease has been found at this point in time is just west of Outlook, Sask., which is south-west of Saskatoon.

“It’s spreading fairly quickly across the province, and it’s now well established throughout the eastern half of the province,” McIntosh said. “One of the main issues is illegal transport of elm firewood. So the major threat to the Battlefords and Lloydminster and so forth is people taking firewood out of the infected part of the province.”

McIntosh added the bottom line is that any transportation of elm firewood should not be done regardless of the location, since it increases the risk of the spreading of the disease.

angela.brown@jpbg.ca

On Twitter: @battlefordsNOW

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