Ecology

On this Earth Day, it felt right to write about one of the most fundamental natural processes that plays out over the surface of the earth: fire.

Forest fires have been part of the natural history of the Canadian Rockies since the return of plants and forests at the end of the last big glaciation. That’s about 13,000 years of wildfire in the landscape. Despite this, people and fire have an uncomfortable relationship. Fires are as natural as sunrise and sunset, and they create some tremendous patches of habitat, favoured by everything from birds to bears to bison. But they can take a real toll on communities, and they produce a lot of smoke, so the usual response to fires is to fight them and put them out, even in national parks.

One of the best tools for bringing fires back into a landscape is prescribed fire, where people (in this case, the Parks Canada fire team) decide when and where they want to have a fire. They can light fires when the weather window is favourable, and do nature’s bidding with a guiding hand.

In 2023, Yoho National Park is in the fire spotlight. In my over 30 years of living in the Rockies, Yoho is the park that’s experienced the least fire, so it’s time. This year, Parks Canada has announced an ambitious plan to light three large prescribed fires in Yoho. They are in out of the way valleys in the western end of the park, but if the park gets the right conditions, it could make for an interesting spring and fall (the park doesn’t do prescribed burning in the summer).

 

We’re in the midst of another historic wildfire season in Canada’s west. But in all the news about evacuations, towns under threat, and area burned (over 700,000 hectares in B.C. so far), you don’t hear much about what happens after the fires have gone out.

Last month, I was in Waterton Lakes National Park for the third time since the big Kenow Fire of 2017. I’ve written about the aftermath of the fire before, in 2018 and 2020, but with each year there are dramatic changes, so this summer I wanted to focus on berries.

I did three days of hiking with my friends Edwin and Alice, and we passed flourishing patches of Saskatoon berries, thimbleberries and wild blueberries. At one point, I stepped into a patch of thimbleberries that were almost up to my shoulders. In the same spot on September 12, 2017, the day after the fire, there would have been dead trees and blackened soil for as far as the eye could see.

How could these berry bushes come back so quickly? To find out, I looked them up in the US Forest Service’s amazing Fire Effects Information System, and the answers jumped out. The entries for the three plants – all with multiple research citations – were peppered with lines like “top-killed plants sprout from rhizomes,” “thimbleberry reaches or exceeds prefire abundance soon after fire,” and “deeply buried rhizomes enable Saskatoon berry to sprout after even the most intense wildfire.” These bushes have come back from roots, not seeds, and with warm black soil, fertilizer from the fire , and lots of sunshine, they are turbocharged to grow.

The upshot is a bumper crop of berries this year, and that’s good news for many mammal and bird species. During my visit, there were already Cedar Waxwings flying around in search of fruit, and I saw a black bear feasting on berries along the Red Rock Parkway.

I worry deeply about people whose homes and livelihoods are threatened by the fires in BC this summer, but in Waterton, the Phoenix is rising, and it will rise in other areas after the burns of 2021 are done.

In late July, I got to return to my old stomping grounds, Waterton Lakes National Park, for my first summer visit in almost 30 years. I got my start there with Parks Canada as a summer naturalist in 1991. I was keen to explore, and to see what the park looked like after the ferocious Kenow Wildfire of 2017.

Well, I wasn’t disappointed. From the prairies to the high alpine, the wildflowers were off the charts, and as was the case when I visited Waterton in the fall a couple of years ago, I wondered if some of these flowers were fire lovers.

The answer is yes. There were Brown-eyed Susans (Gaillardia aristata) galore, and they thrive after fires, not to mention the aptly-named fireweed, which famously colonized the slopes of Mount St Helens a year after it erupted.

But the best discovery of all was the Mountain Hollyhock (Iliamna rivularis). I went for a hike with my longtime Waterton friends Edwin and Alice, and we waded through thickets of it up above our waists. Edwin said he wasn’t sure he’d ever seen it before.

Once I got home to Lake Louise, I eagerly looked it up on my go-to website for fire ecology, the US Forest Service FEIS site, and sent the link to Edwin. Here we discovered that “Hollyhock seeds remain viable for at least a few hundred years!!!” (the exclamation marks are mine) In a study cited from Idaho, researchers found over 100 hollyhock seeds per square foot in a mature evergreen forest, buried 5 to 10 cm under the soil surface. And the seeds need fire: “Seeds have a smooth, hard coat and require a heat treatment for germination.”

 

It was wondrous to see such a beautiful plant rising out of the ashes, and showed that fires and flowers can be unexpected lovers.

October 7, 2018
WATERTON LAKES NATIONAL PARK, Alberta

Part two of our report on last fall’s big fire.

Nadine and I, along with our old friend Edwin, are walking through charred aspen groves on our way to Lakeview Ridge. All around us is a forest of young aspen shoots as high as our knees, sometimes as high as our waists! It’s an exuberant and joyful explosion of life.

We are in the middle of a forest burned in 2017’s intense Kenow Wildfire. About half of Waterton’s vegetated landscape was scorched in the fire, but in the Canadian Rockies, plants are built tough! Lots of species are adapted to come back from these moments of destruction.

The aspen are joined by buffaloberry bushes, sprouting from their deep rootstock. In a year or two, once the bushes start to yield fruit, they will become a key source of food for black bears and grizzlies.

And there are fields and fields of western showy aster. It’s got a great Latin name, Eurybia conspicua, and boy, is it ever conspicuous! There are millions of plants and their puffy seed heads are sporting billions of seeds.

Among these familiar sights, however, is a plant that none of us have ever seen. It’s everywhere, growing close to the ground, and we three “park experts” are in the dark.

At dinner, we go to work to figure out the story behind the mystery plant. First we use Job Kuijt’s epic plant guide to Waterton to discover that our mystery plant is called Bicknell’s Geranium, AKA crane’s bill.

Then it’s off to the internet, where we learn that the seeds of the geranium physically explode out of those crane’s bill seedpods in autumn. They can then stay dormant in soil for centuries, and will only germinate after a fire.

In one study, from the Boundary Waters area of Minnesota, seeds in a 270 year-old forest sprouted after a fire. In a greenhouse test, almost all of the seeds germinated after 10 minutes exposure to temperatures of 65-100° C (150 to 210° F).

This plant loves fire! So why had none of us seen it before? Well, once the other plants and trees start to recover, the Bicknell’s geranium disappears. In some forests, it can cover 25% of the forest floor the year after the fire, but in three to five years… it’s gone.

But it’s not really gone. It leaves behind seeds, and they wait for the next fire, even if it is hundreds of years away.

The forests of Waterton look ravaged, but life will return…