Trees in the Glebe: What do you see? A walk with Owen Clarkin

Humphries, Jennifer Jan 2017 Trees Owen by the tree
Owen Clarkin stands beside a large elm on the avenues in the Glebe.
Photos: John Humphries

by Jennifer Humphries

I had the pleasure of taking a stroll through part of the Glebe on a frosty December morning with Owen Clarkin. Owen is passionate about trees. Though he wouldn’t call himself an expert and is self-educated in this domain, his tree expertise is undeniable. His particular area is nuances for identification of species, the growth and distribution of wild trees, and keeping an eye on what is planted and what is naturalizing or becoming invasive. I first met him when he led a Jane’s Walk (honouring Jane Jacobs’ work to make urban living truly livable) to introduce a group of keen Glebe residents to some of the extraordinary trees we walk by every day and don’t really see.

So what does Owen see?

Our community is home to a variety of tree types, many of them non-native. While some consider such arrivals to be invasive, many are “naturalized” and make valuable additions to the native stock. For example, the Norway maple has a beautiful large leaf and is an excellent shade tree. It is also “urban tolerant.” Still, Owen would like to see a revival of some native maples that are less frequently seen in our neighbourhood and encourages planters to consider the black maple which is less vulnerable to urban challenges such as road salt and is one of Canada’s iconic trees.

It’s an amazing experience to see the trees of our locale through Owen’s eyes. Did you know that we have several black walnuts, not just the occasional “stray” from their typical more southerly range? And that there is a buckthorn on First Avenue?

On our tour we also saw a Bur oak, a swamp white oak, a tamarack and a hackberry. Among non-natives we saw several Nootka cypress (native to British Columbia), Siberian elm and Serbian spruce. There are also many blue spruces, native to the Rocky Mountains in the United States.

Humphries, Jennifer Jan 2017 Trees Tall elm
Elm silhouetted against the sky, a natural work of art

Owen points out the particular look and feel of the bark of various trees. The shagbark hickory really does look shaggy; it’s been described as untidy – but in a nice way! The ironwood, which also bears the charming name “Hop-hornbeam,” has a greyish-brown bark broken into narrow vertical strips.

I’m mourning the loss of a chokecherry in our back yard and mention that the birds enjoyed the fruit. But Owen says that birds feed on more than berries and that almost every tree has edible seeds that provide sustenance to our feathered and furry friends.

I ask Owen what he would like to see planted in the Glebe. He believes we should restore some of the native species that we have neglected over the past decades. We should also aim for greater diversity overall.

We should not restrict our planting choices to exclude trees with known diseases, as is the current approach. Owen encourages tree lovers to consider planting native trees even when they may be susceptible to disease to keep these species population numbers from dwindling away and to give the species a chance at developing resistance and recovering in numbers via offspring. In doing so we are working to preserve our biodiversity legacy. Besides, these rarer trees are often quite lovely.

We can’t fully predict what diseases and environmental factors will affect trees as they grow. We should look at factors such as the soil (the Glebe is primarily alkaline so trees that prefer acidity may not be best), root space and moisture level where we wish to plant. But we should not dismiss a particular tree that we admire on the grounds that a disease may strike in future.

Regarding American (aka white) elms in particular, like Owen, many of us see this tree in its maturity as a kind of natural work of art. There is a stunning American elm on Clemow Avenue, lone survivor of a magnificent elm row. While not suggesting that homeowners take the risk of planting elms near structures where earlier plantings have not survived long, planting them in rural areas for re-naturalization is valuable.

A lot of trees aren’t being planted because it is difficult for local nurseries to obtain the right size for planting. This doesn’t mean that they won’t try to find you what you want. Similarly, the City of Ottawa provides a short list of species that it recommends and will provide to city-owned street frontage, but officials will attempt to provide a different tree type if requested. It just may take longer to get your tree.

Oaks are less commonly planted these days, but they are great strong trees, with a long lifespan and beautiful leaves. Owen points out two young oaks side by side on Clemow, one a red oak that is native to our region and the other a swamp white oak that is more typical along the St. Lawrence.

And what about the Manitoba maple? While it’s not everyone’s favourite, it grows in conditions that other trees can’t tolerate and is a great tree for climbing and hanging up swings.

If you are like me, you grew up thinking that in Eastern Canada there were three types of maple – sugar, red and silver, and that evergreens were either pine or spruce. My knowledge has expanded over the years but my conversation with Owen Clarkin was a revelation.

If you want to learn more about trees in Canada and elsewhere, go to for a list of recommended reading.


Jennifer Humphries is a member of the Glebe Community Association’s Environment Committee, which, in cooperation with Ecology Ottawa, is promoting the planting of 150 or more new trees in the neighbourhood in 2017. Write to Jennifer at

If you want to learn more about Canada’s trees:

The classic Native Trees of Canada by R.C. Hosie, published by Fitzhenry & Whiteside in cooperation with the Canadian Forest Service (now part of Natural Resources Canada), 8th edition, 1979. No longer Canadian-Treein publication but used copies can be sourced online; it’s well worth the search.

En français, Arbres indigènes du Canada. Hosie, R.C. Service canadien des forêts, Éditions Fides, St-Laurent (Québec).

For the Love of Trees: A Guide to the Trees of Ottawa’s Central Experimental Farm Arboretum, from the Friends of the Farm. A tribute to the heritage collection of trees at the Arboretum with 580 colour photographs and 75 drawings of 92 tree species. Published 2007, now in its 3rd printing. To order, click here:

A Natural History of Trees of Eastern and Central North America by Donald Peattie (first published 1948, paperback 1991) is a rich resource of material on native trees. Though US-focused, it covers our region as well and is a fascinating and informative read with references to classical literature.

If you want to learn more about trees everywhere:

The Hidden Life of Trees, by Peter Wohlleben, 2016. German forest ranger-turned-author Peter Wohlleben suggests that trees have social networks, share resources and nurture their young. For an intriguing excerpt, with sumptuous photos:
Click here

Did you know? Canada’s Frédéric Back, National Film Board, won an Oscar for his animation of the allegorical tale by French author Jean Giono: The Man Who Planted Trees, L’homme qui plantait des arbres.
Click here

An essay on the love and loss of a century-old elm,
from The Globe and Mail, Dec. 15:

Goodbye to the giving tree, by Jeffrey Morry
Click here

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