BANFF – Fire plays an important role in many ecosystems.
However, because of fire suppression throughout most of the 20th century, many forests have changed and become more vulnerable to catastrophic wildfires, insects like the mountain pine beetle, and disease.
Parks Canada fire experts say returning fire to the landscape makes for more diverse forests and a greater range of habitat for wildlife like elk, moose, sheep, deer, wolves and bears, and also increases an ecosystem’s resilience to climate change.
Jon Large, a fire and vegetation specialist for Lake Louise, Yoho and Kootenay, said a prescribed fire in the Alexandra River Valley in the northern reaches of Banff National Park last month was the first fire that area had seen in about 275 years.
“Over the five days we got about 1,200 hectares burned, so we’re quite happy with it,” said Large, who was the incident commander on the Aug. 18-23 prescribed fire in the Alexandra Valley.
In the new management plans for Banff, Yoho and Kootenay national parks, Parks Canada has a long-term goal of restoring 50 per cent of the historic fire cycle by 2030 through prescribed fires and managing certain wildfires that are low-risk to communities.
Based on long-term fire cycles, that means at least 1,400 hectares per year in Banff National Park. In Kootenay that means at least 742 hectares per year and in Yoho that equates to approximately 587 hectares a year.
For the Alexandra River Valley, Large said the goal of the prescribed burn was to return the natural fire cycle and create young, fire-regenerated habitat where grizzly bears and whitebark pine can thrive.
“Some studies have shown that some wildlife will avoid these areas of unhealthy, over-mature forest where it’s hard for them to get through,” said Large.
“It will now be much easier for them to walk through, you’ll see a lot more new growth, which is new nutrients and food for the bears.”
The fire also burned in the upper elevations of the valley to help with renewal of whitebark pine, an endangered species.
From bears to birds, many animals rely on the nutritious seeds of endangered whitebark pine trees as a critical food source. The Clark’s nutcracker, in particular, is responsible for most whitebark pine dispersal and regeneration.
“We did a little bit of small-scale burning to create whitebark pine habitat, and that’s going to give us a lot of options, whether it’s natural generation or do we want to augment that with some planting,” said Large.
Jen Beverly, an assistant professor in the department of renewable resources at the University of Alberta, said there are generally lots of benefits to having more fire in parks like Banff, where fire has long been a natural and important agent of ecosystem renewal and also helps to maintain valued habitat.
“Wilderness areas are ideal places to support fire on the land because they typically contain large areas where fires will pose limited threats to public safety, buildings and infrastructure,” said Beverly, who has 12 years of professional research experience in wildland fire science
Beverly said fires create heterogeneity across the landscape, meaning they create patches of land that are dissimilar, and together those patches form a mosaic that provides a diversity of habitat and other ecological benefits.
“We know that when fires ‘reset’ a forest stand by killing the trees, what remains is a fuel-limited patch of land that can have a protective effect,” she said. “By that I mean it can basically serve as a limiting factor for the next fire.”
If there hasn’t been a lot of fire in an area in recent decades, Beverly said it ends up with a lot of continuous, mature forest – so there’s not a patchwork of different land cover types and different forest ages and stages.
“Prescribed fires are a great way to restore that patchwork and effectively ‘cool’ the landscape,” she said.
Before a prescribed fire begins, a plan is drawn up that considers a range of details, including weather and environmental conditions under which the fire will burn and how the smoke will be managed.
In the case of the recent Alexandra burn, there were 28 personnel and four helicopters – three medium helicopters with water buckets to douse fires and one intermediate A-Star helicopter with ignition equipment.
“We had a combination of ignition equipment on this one,” said Large.
The fire crew used a heli-torch, which is a barrel filled with a fuel mixture slung underneath the helicopter. The mixture is ignited on vegetation to quickly burn in the treetops. In this case, the fire team wanted a high-intensity burn for the fireguard ahead of the main prescribed fire.
For the broader area, an aerial ignition device mounted on a helicopter injected small chemical-filled ping-pong-like balls with glycol. Within 30 seconds of dropping from the helicopter, a chemical reaction takes place and the balls burst into flames, igniting the vegetation around them.
“It creates small little spot fires, but we drop thousands of these over the landscape and that’s what starts those small fires that burn together,” said Large.
What was different about this prescribed fire than most of Parks Canada’s prescribed fires was it was done in the hotter, drier summer months compared to the national park’s typical spring or fall burns.
Fire crews took advantage of what they saw as favourable conditions for the 1,571-hectare prescribed fire in the Alexandra Valley, located west of the Icefields Parkway and seven kilometres east of the B.C.-Alberta border and Banff National Park boundary.
The fire rating in Banff National Park was rated as extreme at the time, but fire specialists say the conditions in the Alexandra Valley fell within the criteria listed in the plan – or prescription as it’s called – for the prescribed fire.
An added bonus was forecasted rain about four or five days after the start of the burn.
“The northern part of the field unit of Banff had seen scattered precipitation over the past few weeks, enough to take levels down where it wasn’t as hot and dry as, say, southern Kootenay,” said Large.
Large said the precipitation and temperatures ranges in the area were perfect for the kind of prescribed fire they wanted: to take out 50 to 80 per cent of the canopy in the high elevation, remote area.
“That is what the forest up here would have traditionally gotten and so we needed a hot fire to get those conditions,” he said.
“This was done under the controlled, pre-determined conditions. It just coincided with hot and dry down in the south part of the unit,” he added.
“If we waited until September we wouldn’t get the weather we need… for fires like this we need that high-intensity fire to meet our objectives.”
Large said this area of the park, where there is predominantly lodgepole pine, historically would have seen a fire interval of between 80 and 120 years.
“It just hasn’t burned here for a long, long time,” he said.
Despite some complaints about smoke in the area, Large said there appeared to be overall public support for the Alexandra prescribed fire.
Large said many years ago people were more hesitant when Parks would talk about why they were doing prescribed fires, but he believes the support has grown in recent years.
“If we want to get fire back on the landscape we need to be doing a lot more of these under these kinds of conditions,” he said, in reference to the summer situation.
“There are risks involved and we do our best to minimize the risk.”
On Sept. 3, fire crews started a prescribed fire in the Dormer Valley, a remote backcountry area in Banff National Park approximately 45 kilometres north of the Banff townsite.
The goal of burning this 6,800-ha area is to open up the dense forest and restore grassland meadows to provide critical year-round habitat for wildlife.
In addition, a prescribed fire in a 4,469-hectare area on the benchlands on the north side of the Trans-Canada Highway between Banff and Canmore is on the books this year, too. The burn, however, is dependent on favourable weather conditions.
This area was previously logged and burned in the 2000s.
Fire experts say a re-burn of the site is required to reduce lodgepole pine regrowth, restore montane grasslands and open forests to what was there historically.
Park said these actions will improve habitat for wildlife, such as grizzly bears and create an important fuel break to protect Harvie Heights and the Town of Canmore in the event of a wildfire.
“We’re going to try burning that guard again this fall in preparation for the larger prescribed fire unit next fall,” she said.