Arboriculture

I haven’t written much about Parc Maisonneuve, the giant park that neighbors the botanical gardens and is a short walk from our apartment.

It’s a funny old place. It’s notable for its vast lawns (sometimes filled with dandelions) and its biking/jogging trails. It’s popular with cyclists, joggers, and picnicking families. It’s mostly flat, with a few small hills and one large depression. It’s got a few small ponds, and lots of clusters of trees. These copses break up the sight-lines, and separate the large space into lots of smaller spaces, although some of them are still quite large. The city has 10k runs along the trails sometimes, and down at one end they set up temporary concert and festival venues.

There is a set of paved multi-use paths, and a separate set of gravel paths. They intersect at occasional points, but also approach one another and then swerve off in others. There are also small unofficial paths through many of the tree clusters, some of which hide the views of the grassy areas and make it feel like you’re entirely off in the woods.

All these features combined result in it being very difficult to maintain a coherent mental map of the place. There are many distinct spots, but there are also places that are sufficiently similar that you might confuse them for one another if you approached from a new direction.

I’ve taken to heading over there in the morning for a pre-work walk. There are limitless ways to loop around, depending on whether I want sun or shade, open areas or forest, to be solitary or see other people.

Today on my walk, I saw a squad of very athletic looking young men and women wearing matching sweatshirts, gloves, and carrying buckets. Their leader wore a high-vis vest and carried a clipboard. Something was up!

One woman was kneeling by a tree a ways up ahead of me, and working her way around the tree. By the time I got to where she was working, she’d run off to another. The tree she’d left, however, had evidence of her work.

Now, near one entrance to the park, there has a sign about actions the city is taking to help control the Emerald ash borer (Agrilus planipennis), an invasive beetle that’s devastating the native ash tree population. Their presence was first confirmed in Canada in 2002, but they have already spread significantly. They will generally kill a tree in two to four years; virtually all ash trees die within ten years of being infested. This sign mentions that the city will be removing damaged trees, and the work would mostly be done between September and March.

What was the deal with this crown of spikes I saw? It’s an inoculation effort! The workers are applying TreeAzin, a pesticide that flows into the sap (I learned the word “translocate” from their FAQ) and prevents infestation of the ash borers. It’s a strategy that works in an urban environment where workers can reasonably access the individual trees (and apparently, the trees are most susceptible to infestation in urban areas).

Some of these ash trees are beautiful, large shade trees, and though there are also other species of trees in the park, it would certainly be poorer without them.

This fascinating site has a map of all the different types of trees in the city. Here’s what it shows for different species of ash in the area of the park (each colored circle represents one tree).

I don’t know if this effort will succeed, but I hope that they are able to save the ash trees.