On Wednesday afternoon, plumes of grey smoke billowed into the air above High Park and wafted across the city. But this was no ordinary brush fire. It was a controlled burn, initiated by the City as part of the High Park oak savannah and restoration program, which has been in place since 2000. Two plots of land in the park were burned in methodical fashion, drawing in spectators from all around.
Burning off ground leaf litter helps control invasive species and restores the black oak savannah, an endangered ecosystem that has also been designated as an “area of natural and scientific interest” by the Ontario Ministry of Natural Resources. About a third of High Park is black oak savannah, and less than one per cent of Canada’s original black oak savannah remains today. Agriculture, invasive species, and urban development have all contributed to its decline.
While a grass fire may seem destructive, it’s part of the natural order of things. In the wilderness, a grass fire can reduce a large swath of forest to cinders, but it always gives way to new growth. Causing our own fires is a necessary measure to restore this fading ecosystem and protect it from the invasive species that are keeping new black oak trees from replacing the old ones.
Jason Sickel, of Lands and Forest Consultants, was the burn boss for this year’s fire. He explained the science behind the prescribed burn, and what his crew’s approach would be.
“Oak savannahs are heavily reliant on fire to keep invasive species at bay,” he said. “The oak has evolved to incorporate fire into its success, down to its leaf structure where it doesn’t decompose as fast. It holds over to the spring. It curls in the heat. The bark is a lot hardier than a lot of other hardwoods. It has that superior taproot so that when fire does progress over a site and top-kills the shoots…all that energy gets compartmentalized in that taproot and it shoots up a new sprout that will far exceed what would have been there previously. You’ll have three to five feet of growth on top of what would have been there. No other hardwood species, or invasive species, can do the same, which is why fire is such an important process of maintaining and developing oak savannah.”
Before starting any fires, Sickel and his team took a number of things into consideration, including temperature, humidity, moisture in the ground cover, and wind speed. The burn team used those factors to calculate the fire’s rate of spread, and what type of fire they expected to see. Sickel was anticipating an R1 or R2 fire, meaning the flames would be from 30 centimetres to 1.5 metres tall, and maybe up to two metres in the areas with the thickest leaf litter. Conditions on the sunny Wednesday afternoon were perfect. “It’s a great day for a burn,” Sickel said.
Fred Bruin—who, like Sickel, works for Lands and Forest Consulting—was the ignition boss for this year’s burn. He drove an ATV with a flaming nozzle mounted on the back. As he slowly roved around the edge of the burn areas, it sputtered a mixture of diesel and gasoline that instantly set the ground aflame. After sweeping the perimeter, he covered the interior of the plot. The smoke was thick and the campfire smell was heavy in the air. “Did anyone bring marshmallows?” someone joked.
A suppression crew patrolled the area with water tanks on their backs and spray guns in their hands, ready to quench any stray fires. There were none, and the burn went off without a hitch.
Councillor Sarah Doucette (Ward 13 Parkdale-High Park) was in the park during the burn. She seemed pleased with the success of the restoration program. “Come back here in two weeks time and you’ll already see things growing,” she said—the field before her smouldered, covered with black and grey ashes
“It does enhance them and they do grow quite quickly,” she added. “It really does help us keep our black oak savannah, which is important for High Park. If this is what we have to do, then—oh heck, it’s a beautiful day out,” Doucette laughed. “A little bit smoky, but a beautiful day out!”