Take a stand for the mighty elm tree

Elm tree leaves

They keep us cool during the summer, give us shelter from frigid winter winds and clean the air we breathe. Trees play an important role in the sustainability of our towns and cities. A healthy urban tree canopy helps regulate temperatures, protects against ground erosion (think floods), and provides shelter for local wildlife.

Maintaining an urban canopy isn’t as simple as planting trees anywhere. Trees are planted based on longevity, drought resistance and the climate zone they flourish in. One example, the American Elm Tree, is not native to Alberta, but has been planted here for over 100 hundred years because it’s drought resistant, grows tall, has long leafy branches and can withstand Alberta’s harsh winters.

How many trees does Fort Sask have?

Three years ago we catalogued 20,000 on our boulevards and in our parks, of those, 6,000 are green ash and 4,500 elm trees, these numbers have increased since then.

Why is it important to diversify our urban canopy?

That’s the present-day reality of our urban forest, our elm trees are under threat from disease carrying pests. Other trees species like linden, silver maple, bur oak are also planted to diversify our urban canopy, this helps to ensure one type of pest invasion doesn’t wipe out all the trees. It also adds visual interest with leaf textures and fall colours. Currently, elm trees are the under the greatest amount of monitoring.

What could kill our elm trees?

It’s hard to believe a 30ft tall tree that can withstand Alberta’s harsh winters is endangered?

Dutch Elm Disease (DED) is caused by the fungus Ophiostoma novo-ulmi and is responsible for the death of millions of elms. The fungus is spread by the Elm Bark Beetle when it stops to feed on healthy elm trees and breeds in dead and dying elms. Once a tree is infected with DED it can die within three weeks, although some infected trees have survived, but not without battle scars.

Where is DED from and how’d it get here?

Its origins can be traced back to Asia where over millions of years the elms there have developed a resistance to the fungus that causes DED. However, the European and American elms have ZERO resistance. Its introduction to North America can be traced back to 1931 when a furniture company in Cleveland, Ohio unknowingly imported infected wood from France. From there it spread northeast across the US and to the great lakes region.

DED was first discovered in Eastern Canada in 1940, then Manitoba in 1975 and Saskatchewan in 1981. As DED moved west, it decimated Elm trees across Canada and the United States. In City’s like Detroit (aka the City of Trees) and Winnipeg grand elm tree lined boulevards turned into a distant memories in a matter of months.

Winnipeg Street before DED    Winnipeg Street after DED
Photos: Mike Allen, former City of Winnipeg forester

Detroit Street before and after DED

Presently, Alberta and British Columbia are home to the last DED free elm stands in the world valued at over $1 billion. Which is why it’s so important everyone does their part to prevent the spread of this deadly fungus. Our trees protect us, now it’s our turn to protect them.

Below is a video about DED, the fashion is a bit outdated, but the information is still relevant. Plus it’s fun trip down memory lane.

DED Taking the Last Stand Part 1 (Video)

Note: since this video aired, Alberta had one reported case of DED in 2020 in Lethbridge, and another case in Wainwright over 20 years ago.

What’s Fort Sask doing to stop the spread?

For the prevention of DED there’s signage and enforcement across Canada to stop the spread. The best mitigation is not moving firewood, especially across provincial borders. Aside from prevention, City arborists use pheromone traps that are sent to a lab in Edmonton for testing

If for any reason an elm needs to be pruned during or after the ban, all our tools are sanitized after every cut, stumps are ground out and buried under at least 10cm of soil and all elm material is chipped so the scent doesn’t attract the elm bark beetle.

As mentioned earlier, we plant different tree species to diversity the City’s urban canopy, so if there’s a case of DED our overall urban canopy is less impacted. 

What can you do to stop DED?

Here’s part two of our documentary. It talks about prevention and control measures being used in Alberta and in Canada. Again, the fashions have changed, but the information is still correct.

DED the Last Stand Part 2 (Video)

Luckily, the City of Fort Saskatchewan has never had a reported case of DED, and it’s everyone’s job to keep it that way. We really are taking the last stand to protect the last DED free elm stand in the world. We urge you to follow pruning bans, fire wood transport bans and learn the symptoms of DED.

  1. Follow the annual pruning ban. NO pruning from April 1 to September 30.
  2. Learn to identify the signs and symptoms of DED:
    • Leaves on some branches suddenly wilt, droop and curl
    • Leaves in places turn yellow, then brown and shrivel, but stay on the tree
    • The bark on infected branches is dark brown or has red streaks
  3. Report all suspect trees immediately to the STOPDED Hotline 1-877-837-ELMS (3567)

Learn more about StopDED and how you can get involved.

Resources

dutchelmdisease.ca

dutchelmdisease.ca/history

dutchelmdisease.ca/about-dutch-elm-disease

alberta.ca/society-to-prevent-dutch-elm-disease.aspx

 

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