A walk through Calgary’s young, urban forest

Nora Bryan, For the Calgary Herald 



A walk through the Douglas Fir Trail in Calgary’s Edworthy Park is an otherworldly experience. The dim and cool forest floor is protected from the relentless prairie sun by the towering spruce and Douglas firs that grow there. These trees have an unlikely home east of their usual mountain habitat, fed by natural springs along a favourable north-facing slope. Of moss, moisture and mushrooms, this place is more like British Columbia than the high prairie foothills.

These trees have been here for a very long time. Native groups used to make bows from the strong wood of the Douglas fir; in fact, this is how the Bow River got its name. These stoic trees will remain here as long as the ecology works for trees.

A short walk to the top of the slope returns you to dry prairie grasses, wild roses and wolfwillow. Centuries of soil built under a relentless westerly wind, a baking sun and a stone cold winter make this more naturally the realm of grasses.

What does this mean for our urban trees? It means that Calgary’s urban forest is three things: in a place not meant for trees, mostly planted, and still very young.

Newcomers in a foreign land

That trees can thrive in a world not made for them is impressive. Out east, even where the hardwood forest has been carved out for roads and homes, there are still remnants of a soil that was built by and for trees. This soil contains the fungi and organisms that trees evolved with. Although some fungi rot trees, others are valuable partners. The soils here, even when not trashed and compacted by construction, are a foreign substance to trees. Yet they adapt in spite of the strange place they find themselves.

Gardeners can make a tree’s world more hospitable by applying a surface dressing of compost and a thin layer of wood mulch every year. This will help build the moist, organic-rich soil that trees love best. In time, perhaps the fungus-rich soil so valuable for trees will become established in this vast urban island.

Settling in

Where forests once belonged, trees will try to grow again. Here, if we want trees, we must plant them. Sure, some trees do seed themselves. Ash, Manitoba maple and choke cherries sometimes grow from a seed wedged along a fence line, or a fruit dropped by a passing bird. But mostly, we put them there.

Being stuck in the ground after being hobbled in a small plastic pot is a stressful thing. The best thing you can do for a new tree is to plant it at the right depth. A properly planted tree will reveal a trunk flare at ground level just above the first roots.

This may mean the tree needs to be staked for its first year. Stakes or guy wires should be somewhat loose and removed after the first year or two at the most. Do not let ties bind.

Deep planting is one of the most common causes of tree failure in the first few years. I cannot say this often enough (I may make it my personal motto).

Where to, now?

Finally, I wonder at the youth of our urban forest. The original Memorial Drive poplars have aged and fallen apart. Birches in many older neighbourhoods have died back. These are normal and natural events — well, at least as natural as an urban environment allows.

We are seeing how trees live and die here being played out pretty much for the first time. Perhaps your grandfather was one of the first pioneers to break the ground here on the Canadian western plains. We are still figuring it out. Observe and learn about your trees: you are a pioneer gardener!

