The era of megafires

The era of megafires

Wildfire expert says changing forest ecosystems contributing to large wildfires.

Forestry management policies in the western United States have contributed to a new era of mega-wildfires, says an expert who delivered a public presentation alongside local emergency personnel at the College of the Rockies on Monday.

Dr. Paul Hessburg, a research landscape ecologist with the US Forest Service who has spent the last 30 years studying forestry and fire behaviour, focused his presentation on factors that have contributed to the rise of large wildfires over the last 80 years.

It was an apropos conversation given the wildfire situation in the BC Interior, as 218 fires are currently burning across the province covering over 40,000 hectares.

Dr. Hessburg opened the discussion with a personal anecdote of how his home community of Wenatchee, WA, experienced a wildfire threatening the community in 2015.

He reflected back on the incident as he shifted the presentation to the history of the US Forest Service and the dual relationship between the removal of large, fire-resistant trees on open rangeland landscapes and the increasing effectiveness of wildfire suppression.

Denser forest landscapes that were traditionally renewed and regenerated through natural grassland wildfire, combined with a focus on extinguishing wildfires as quickly as possible, has given rise to forest landscapes that can spread quickly and burn hot.

“It’s pretty important to understand that fire has a role in the natural landscape, and it’s a pretty big one,” said Dr. Hessburg. “Everything that lives in the woods and on the range actually depends on building a life history with wildfire. For thousands of years, most of the native plants and animals that we’re aware of, have actually adapted to fire — some even require it in order to survive and complete their life cycle.”

Dr. Hessburg cited Ponderosa Pine, which has a thick bark that is fire resistant and can protect the tree, while burned forest grasslands allow seeds to germinate. Bird species use burned trees to knock out cavities for nests, while ungulates such as deer or elk feed on plant life that thrive after a fire event.

Dr. Hessburg showed photographs of the same landscapes taken in 1930 and in 2010 that showed just how creeping forest growth had replaced what was once an mostly open grassland range.

“These grassy areas were capable, often, of supporting forests that a grass fire cycle kept them in grassland, so you had this very patchy grass with forest,” Dr. Hessburg said. “Elsewhere in the forest, fires were frequently thinning the forest, maintaining open canopy conditions and this actually reinforced the likelihood that the next fire that came along wouldn’t be severe — it’d be a thinning fire.”

Logging also played a part, as large, old trees were removed and replaced by a younger, denser forest that wasn’t fire-resistant and couldn’t sustain that grassland wildfire lifecycle.

“The logging was removing the larger fire-tolerant trees, survivors of centuries of fires,” Dr. Hessburg said. “These are the big ponderosa pine, douglas fir, the western larch, and they were being replaced by thin-bark, fire-sensitive, shade-tolerant Grand fir, White fir, Douglas fir and Lodgepole pine. Decade after decade, fuels after logging were simply accumulating on the forest floor.”

He walked back through history, noting that forest landscapes had been managed by Indigenous Peoples who understood the value of controlled grassland burns before European settlers had come out to the American West in the mid-1850s.

“They were burners, and they were capable fire-managers,” said Dr. Hessburg. “They created forage areas around their encampments for deer and elk and bison that they hunted. They didn’t have to go far. And later when they had large horse herds, they pastured horses in areas that the burned for the graze.

“…One of the most important things they figured out by living on the landscape in a wildfire environment, they figured out that if they burn in the spring and the fall, they can avoid most of the out-of-control summer fires. That’s a big idea and they figured it out a long time ago.”

While settlers adopted the Indigenous practice of controlled burning at first, that fell away after the U.S. government removed Indigenous populations to reservations, Dr. Hessburg said.

Other impacts interrupting the ecological lifecycle include a massive introduction of livestock that decimated grasslands, the traditional conveyer belt for grassland wildfire. Railway construction and new towns springing up on the American frontier also began to criss-cross the landscape, blocking the natural flow of grassland wildfire.

From the 1930s, increased funding to the U.S. Forest Service led to increased success at fire suppression, however, by the 1980s, the focus on putting out wildfires as quickly as possible had led to a huge fuel buildup, which is a catalyst for the huge wildfires that burn thousands of acres.

Moving from forest landscapes and factors for large wildfire events, Dr. Hessburg shifted to the wildland urban interface (WUI) — the zone between human developments and unoccupied forested lands. Costs to fight wildfires in the WUI skyrocket when factoring in personnel and equipment, when prevention can mean only spending a fraction of that incurred cost.

“For us, the time to decide on where to build, what to build with, designing in defensible neighbourhood plans, and separate roads in and out of developments — that’s well before the wildfires,” Dr. Hessburg said. “Once the wildfires are roaring, it’s typically too late.”

He put out a call for action on tackling the threat of large mega-wildfires, noting that it’s up to the public to get educated on the matter and press for changes. Lobbying government to utilize tools such as prescribed burning, selective mechanical thinning or even managed wildfire — controlling and steering a wildfire to burn out appropriate areas — will be key to preventing large wildfires. Especially without prescribed burning, mechanical thinning becomes a huge piece of the solution, he added.

“Until we, the owners of our private lands and also our public forests lands, claim that it’s our high priority and our responsibility, we’re on a path to continued losses to these large and destructive megafires,” said Dr. Hessburg. “As individuals, we have a responsibility to make our homes, our yards, our communities fire-resilient. It’s up to us.”