Replanting forests after wildfires comes with complex challenges, but there are opportunities in the ashes

Early last September, firefighters were in the final stages of containing a 33,000-hectare wildfire complex in Alberta's Jasper National Park. Elsewhere, park workers were already replanting the first batch of trees in the recently scorched earth.

The Douglas firs were chosen because they resist fire better than other conifers, according to Marcia DeWandel, vegetation restoration specialist for Parks Canada.

However, replanting so soon after a fire is much more exception than rule. Replanting is typically expensive, time consuming, labour intensive — and doesn't always work.

DeWandel says they were able to move so quickly was because they had already done the necessary studies and surveys for replanting the area and — most importantly — they already had the seedlings, which can sometimes take years to source and grow.

"That wasn't necessarily the plan, because we didn't know the fire was going to happen," says DeWandel. "But we did have these seedlings on hand for other restoration projects, so we did end up putting them in some of the burned areas at that time."

She notes they were already seeing an "amazing" level of greenery re-sprouting after the fire, which showed the soil and root network were "somewhat intact." She says they prioritized replanting recently-burned areas near wetlands, erosion-prone slopes and frequently used trails — though planting has since paused while they monitor drought conditions and destructive cutworms that tend to breed in severely burned areas.

This year is already Canada's second-worst wildfire season on record, with more that 7.3 million hectares — roughly the size of New Brunswick — burned so far. And that's on the heels of the previous two years of devastation, including Canada's worst wildfire season in 2023.

As climate change makes wildfires more intense, experts suggest the forests we rebuild most likely won't resemble what was there before. But given enough time, there is an opportunity to grow back healthier and more resilient.

In most cases, it can take years for replanting to begin after a fire.

Northwestern Ontario's Ogoki Forest was the site of intense fires in 2023, which scarred more than 40,000 hectares of pine- and spruce-covered landscape, much of it vital caribou habitat.

Located about 400 kilometres northeast of Thunder Bay, Ont., replanting efforts in the boreal forest are only just starting to take root — more than 700,000 sets of roots.

"It's actually really important not to speed and just go right after a fire," says Jess Kaknevicius, CEO of Forests Canada, one of the organizations supporting Ogoki's replanting.

After a fire, Kaknevicius says there could be years of surveys and assessments before planting can begin. That includes the initial safety assessments, looking at what is growing back naturally, where replanting will have the greatest effect and what to plant.

There's also the matter of sourcing seeds from the burned areas, which are cultivated into seedlings at nurseries for up to two years before they can be hand-planted.

"If you need 500,000 to 1,000,000 trees, they're not just sitting there waiting for you," says Kaknevicius. "People don't realize that seed is a very, very precious commodity and is one that is being impacted by climate change, too."

After planting, it's a matter of returning to the site at the one-year, two-year, and five-year marks to see how they're growing. "The overall process, if you think of it, from seed to survival, is anywhere between five to eight years," she adds.

In some replanted areas, ensuring survival is easier said than done, especially when dealing with other effects of climate change.

In 2017, the Elephant Hill fire burned more than 192,000 hectares of the B.C. Interior, roughly 100 kilometres west of Kamloops.

Three years later, the Secwepemcúl'ecw Restoration and Stewardship Society — formed from eight First Nations communities affected by the fire — began hand-replanting a mix of cottonwood, aspen and willow along the Bonaparte River.

However, almost none of the initial batch survived the next year — seedlings baked in dry earth as the 2021 heat dome brought temperatures approaching 50 C to the region.

"There was a huge mortality rate within all of the planting within B.C. that year," says Angela Kane, CEO of the society. "So we had to sit down and think about what's next, what's a better way to plan it?"

One solution? Dig with high-power pressure washers.

"It disperses enough of the dirt and just totally saturates that area [with water], so it gives it a really good head start," says Kane. "And it's twofold. The same equipment that you use for the planting, you can then turn around and use for firefighting in your community as well."

Another challenge is the land itself. When a fire burns too hot and deep, it can create a glass-like layer that repels water, which Kane says cannot be replanted even with human help. "It's just a dead moonscape," says Kane.

Not burning deep enough can come with other problems, according to Victor Danneyrolles, a forest ecologist at the University of Quebec at Chicoutimi.

He says the organic top layer of soil contains fewer nutrients and retains less water compared to the mineral soil underneath. If the organic layer isn't burned away, it needs to be cleared with heavy machinery before planting — which, at more than $2,000 per hectare, adds up very quickly when hundreds of thousands of hectares have burned.

To solve that issue, Danneyrolles is helping develop seeds coated in nutrients and water-retaining material, which can be dropped by drone into hard to reach terrain. He says the coating helps seeds take root in organic soil more easily, and skips the step of cultivating them into seedlings first.

While an out-of-control forest fire might not be ideal for the health of an ecosystem, the blackened blank slate that remains does bring opportunities for change.

"Most of our replanted forests are black spruce, which is great for the forest industry. But we have alternatives that can be more resistant and more resilient to fires," says Danneyrolles.

Danneyrolles says that could be a less commercially desirable but faster-growing conifer such as jack pine, or less-flammable deciduous species such as white birch or aspen, which can act as a natural fire break.

But focusing on just one type of greenery risks missing the forest for the trees, says Amy Cardinal Christianson, senior fire advisor with the Indigenous Leadership Initiative.

"I think we need to lose our obsession with trees," says Christianson.

She says promoting a greater range of native species such as berries and medicinal plants, as well as allowing some areas to return to grasslands rather than forest, could go a long way.

"I don't think we'll ever get back to the way it was," says Kane of the efforts at Elephant Hill. "Our goal is to try and create something better than what it was."