Invasive species in the line of fire

[attach]5654[/attach]High Park went up in smoke on the afternoon of Mar. 21.

Fire swept across the forest floor during two controlled burns designed to help promote the growth of rare plant species native to the area.

“High Park is one of the most unique ecosystems because of its location within a large urban area,” said burn boss Fred Bruin as smoke billowed all around and a fire raged behind him. “It’s an endangered ecosystem and the only way the ecosystem can regenerate itself is through fire.”

A crew of 12 from Lands and Forest Consulting began by spraying a mix of diesel fuel and gasoline on the ground to act as an ignition source for the blaze to come. Bruin said the nine litres of fuel sprayed on the ground wouldn’t contaminate the delicate ecosystem.

As fire officials set and monitored the burn police and volunteers helped to control the crowd who showed up to watch the spectacle.

However, the smoke itself was more effective at getting the crowd to move than were the humans.

Signs scattered around the park and near Bloor Street West informed passers-by that the fire was done purposefully and not to report it. Although many members of the crowd came within a couple of metres of the flames officials said the fire posed little threat and closing the park for the day was not necessary.

[attach]5655[/attach]“It’s so much fun to watch, why would you want to close it down?” said Beth McEwan, urban forestry coordinator with the city. “We want to educate people about the process so we don’t want to close the park. We want them to be part of it if they want to.”

This was the ninth controlled burn in High Park since 2000. McEwan said in the past the burns have been effective in deterring the growth of invasive turf grass in the park and encouraging native species to grow in its place.

“We saw a great benefit last year,” McEwan said. “The volunteers had done a lot of planting in two large patches.

“Doing a second burn will further expand those plants and invigorate them and help them to take over the site.”

Bruin explained how the process works.

“Once the area’s turned black, when the sunlight’s coming in on it, it raises the temperature by 0.2 degrees Celsius, which stimulates the native plants and sets back the cold weather plants,” he said.

Little notice is given before the burns take place as the timing of the event depends on weather conditions. This year the public was given 24 hours notice.

Although past burns in High Park have usually been performed in April, the unusually warm weather gave the city an opportunity to get started early.

“We’ve got beautiful clear skies, we’ve got the right relative humidity, the right temperature, and the right wind and the right direction,” Bruin said.

[attach]5656[/attach]The native oak trees in the area also serve as a home for animal and insect species. While McEwan admitted the burn might result in the death of some insects, she said precautions are taken to ensure minimal damage is done to their populations.

“That’s why we only burn in sections,” she said. “You have to do the burn to benefit the environment that they need to survive in the long term but you don’t do everything at once because you have to make sure they survive in other areas of the park.

“We do work with entomologists in helping to make those decisions about where to burn and he’s asked at times that we consider not burning areas because he’s seen butterflies that are rare and he doesn’t want them to be destroyed.”

While she said the city is not concerned with invasive insects damaging the oaks there are some fungi in the states that officials are keeping track of.

While found in other pockets of the city and southern Ontario, High Park has the largest oak savannah ecosystem in the city, according to Bruin.

“It’s just a marvellous thing that the City of Toronto is doing to help this ecosystem, an endangered ecosystem,” he said. “Oak savannah is the most endangered ecosystem in the entire world.”

Share on Facebook

Tweet

Save