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Canadian Urbanism Uncovered

Tree Tuesday: A mature elm is hard to find

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Every Tuesday, Todd Irvine of Local Enhancement and Appreciation of Forests (LEAF) will post a stop from the Toronto Tree Tours, a collaborative project of LEAF and the Toronto Public Space Committee. The Toronto Tree Tours offers walking tours in neighbourhoods across the city as well as virtual tours on its web site. The aim is to introduce Torontonians to the individual trees in their neighbourhood while telling stories of our city’s ecological and cultural history.

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Dovercourt Park and Neighbourhood: Stop 6

This large American elm (Ulmus Americana) is believed to be at least 80 years old and was likely planted in this yard after the house was built in the early 1900s. Its age is noteworthy, as it means that it is a survivor of the outbreak of Dutch elm disease that swept through the city in the early 1960s, killing over 80 percent of Toronto’s 35,000 elms. Many of the elms lost were mature trees planted at the turn of the 19th century. They often lined both sides of city streets, their arching branches meeting in the middle to create a cathedral-like canopy more than 50 feet above the road below.

The disease was accidentally imported from Europe on trade ships and is inadvertently spread from tree to tree by the elm bark beetle. Once deposited under the elm’s bark by the burrowing beetle, the disease begins to spread. The tree reacts to the presence of the fungus by plugging its own phloem and xylem tubes that transport nutrients and water up and down the tree just under the bark, often starving a tree to death within a year.

Unfortunately, despite its resistance to Dutch elm disease, this tree died in the spring, likely due to the homeowner installing a new walkway and a raised stone wall around its base last summer. At the time, large roots of the tree were cut to make room for the wall. Many people don’t realize that the majority of a tree’s roots are in the top 2 feet of soil and are vital to the tree’s survival. If its roots are cut, a tree cannot absorb water from the ground and will often die as a result.

Upcoming tours: Green Roofs and Trees Tour
When: Saturday, August 4, 2007 @ 1:00 pm
Where: 401 Richmond Building

Check out the profile of LEAF in today’s Toronto Star.

Photo by Dougal Bichan



  1. I hate these old trees. They’re always shading my house, and dropping crap on my cars. In the fall, it takes me hours (on several occasions) to blow the leaves onto the street with my 2-stroke leaf blower.

    But seriously, are those smaller trees planted too close to the street?

  2. Despite having inhaled too much CO, David is right – elms are a real nuisance, despite being majestic looking trees. I grew up in the Greenwood-Danforth area and we had some huge old elms in the backyards between us and the street behind, most of them are still there, bigger than ever… except in the spring they drop those damn disc-like seeds (they come down like snow), in the summer it’s dry leaves and branches, and in the fall, the endless falling leaves form a carpet in the yard and take several rounds of raking (my Dad and I never resorted to noisy polluting leaf blowers) to clean up the leaves. It seemed as if there was alwys something falling from those trees. The ones in the east end managed to survive the Dutch elm disease, and I think they really add a lot to the character of my old neighbourhood. They make good trees for ravines and places that don’t need to be kept clean, but I wouldn’t plant them as street trees because of the mess they make. If the City planted seedlings from the disease-resistant specimens, they would really help create a good shade canopy in a lot of tree-barren places.

  3. Many trees are messy. Elms blanket the ground with their detritus. Mulberries leave a slick of juice in early summer. Crab apples drop their fruit for months. Maples pour down leaves like a deluge. Even cedars and pines dump deep carpets of needles and fronds.

    But what’s the big deal with raking? Or, better yet, leaving some of this material to enter the ground as compost? Isn’t that part of its purpose? If the quantity seems large, put the excess out for collection, but it’s very easy to compost leaves in bags over the winter (chopping them up makes them rot more quickly), adding them to your composter in the spring and using the result as mulch throughout the summer.

  4. Robert > I have to agree with Amy, all trees are to some extent “messy.” We need to acknowledge that nature is random and does not necessarily adhere to our rigid notions of order. A city devoid of seeds and leaves, while reducing raking time, is a sterile place to live. If we wish to capitalize on the many benefits that trees provide we need to be at peace with a bit of mess.

  5. Funny, I never considered the stuff that drops from trees as messy (except for bird droppings). People think I am nuts when I tell them I want to have a big sugar maple in my backyard, but nature is supposed to be messy, we are the ones that should adapt to its mess, not the other way around. I appreciate the manicured gardens as legitimate art forms, but I prefer a garden with trees, flowers and plants that aren’t planted in a too orderly fashion. One more thing, people who use leaf blowers deserve their clogged arteries due to a lack of exercise.

  6. Messy trees are not a problem if people do the things that you suggest. However, many homeowners can’t be bothered. We cleaned up the stuff from the elms because there was just way too much of it. I like natural gardens, but when you have elm detritus everywhere, it does stifle other plants, and those things start sprouting everywhere like weeds. My Dad also grew a great vegetable garden every year, so we did a lot of gardening. The volume of falling “stuff” was overwhelming, especially with a half dozen VERY large (four storey tall) elms around. Believe me, if we didn’t have to rake, we wouldn’t have. The problem with having elms as street trees is that the detritus accumulates on the storm drains and in between houses, and sadly many homeowners can’t be bothered to keep these areas clear. We had a neighbour that never cleaned up beside their house, just kept piling dead leaves and garden stuff up. Eventually the Fire Dept. actually got them to clean it up as all the dry stuff next to the house was more of a fire hazard than anything else. The ideas posted by the various posters are great, but it takes committed and caring people to keep them up. We’re in the middle of a very dry summer, and how many can’t even be bothered to water their trees, especially the smaller ones? If those trees don’t survive, then the city’s famous tree canopy will be history, and I will be very sad to see that happen. Encourage your neighbours to keep their trees well watered, even if they don’t water their lawns! We need our trees!!!

  7. People who brick over the roots of their trees drive me nuts – the tree will die and fall on their house and then they will ask why the city didn’t cut it down!

  8. Mature elms are getting perhaps endangered with hot smoggy drought-ish summers – at least I’ve noted a wide range of good big elms failing to survive though they deserved special treatment/care. Maybe we need a tree advocate eh?
    And trees being messy? – what about humans?!! – speaking for mesself that is…

  9. Trees are not the organism that has to go…