Vik Pahwa's picture
Posted by Vik Pahwa /
Fire in High Park; Prescribed burn of Black Oak Savannah
Last Wednesday High Park was set on fire - intentionally. There was excitement in the air - the tension of an imminent forest fire and police officers standing by mixed with curious onlookers and reporters waiting with anticipation. I was about to witness a prescribed burn.



Similar to how a doctor may give a prescription for medication when sick, this prescription for parts of High Park called for a grassland fire to invigorate growth. The areas to be burned are a rare plant community called black oak savannah, characterized by “widely spaced black oaks, scattered low shrubs and a rich variety of prairie grasses and wildflowers.”


It may seem odd that fire is necessary for ecosystem management, but this type of plant community requires fire that encourages dormant seedlings to grow. When the heat increases to the necessary temperature, the buds increase activity and a growth spurt results. The mature trees are not affected by the fire as they are protected by thick and tough bark. Any young trees are protected by metal stove pipes placed around the base of the trunk.


Fred Bruin, of Lands and Forests Consulting, the lead forester and fire boss for the prescribed burn team, mentioned that Toronto was fortunate to have High Park cared for so well that prescribed burns are permitted in an urban environment. We are indeed fortunate as less than 1% of the original area of this kind of habitat remains in Ontario.


Fred Bruin


Bruin could not have been happier with the weather conditions – the temperature, relative humidity and wind speed were all within the “window of opportunity.” Many details go into a prescribed burn. He also talked about fire prediction terms such as fine fuel moisture code, initial spread index and fire weather index, all technical terms that he explained meant the time was ideal to burn. Interestingly enough wind direction is not considered as important. Spring is a good time for such ecosystem management; with little green grass, the amount of smoke generated is kept low.


The areas to be burned were 1.5 hectares and 1.9 hectares in size. The first area was within 125 metres south of Bloor Street and police were ready to stop traffic if necessary. This area was burned before traffic became heavy. The second area was farther into the park and traffic would not be affected, but it offered another challenge – a slope. According to the prescribed burn team, fire travels at least nine times faster uphill than downhill.


In each case, the edges of the savannah blocks were burned first to minimize the risk of fire spreading out of control. With hills being so much more challenging a larger edge was burned around the boundary. Fires would be started with torches attached to all-terrain vehicles and hand-held torches. Although the fuel used was a mix of diesel and gasoline, we were assured that very little fuel would be needed.


High park prescribed burn


Every member of the prescribed burn team was a professional firefighter, some designated Ministry of Natural Resource firefighters, and had been involved in the planning process since September of last year. The team of six have a combined 140 years of firefighting experience in municipal and wildland fires.


During the briefing safety was emphasized several times. Toronto Fire was alerted to not respond to calls that High Park was on fire but were ready to respond in case. Each team member was trained in first aid and carried walkie-talkies and cellphones to keep in touch with the rest of the crew. Finally, the second fire would not be started until the first one was complete.


After the media scrum was over, it was time for ignition! And Bruin said that “it was gonna be easy.”


It was exhilarating. Onlookers watched the fire creep across the ground, listened to the crackling of burning grass and watched a wall of smoke rise into the sky shrouding the trees, impervious to flames, with an apocalyptic air reminiscent of a forest torn apart by war.


It did not take long. The first block was done in 25 minutes and the second in 35. All had gone according to plan. Two team members wandered the burn site immediately after the fire to put out stubbornly burning logs and or dead snags. The stark contrast between burned and unburned areas of High Park was remarkable.


High Park prescribed burn


In the end, onlookers left smelling like campfire knowing that this controlled blaze, unlike the arsonist’s destruction of the beloved Jamie Bell playground only days earlier, has made a difference to the endangered black oak savannah that is so characteristic of High Park. We may not see the results of this prescribed burn in our lifetimes but our children and grandchildren will.


Vik is a Toronto-based urban explorer, aspiring photographer and armchair arborist. He is also a long-standing LEAF volunteer. 


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