The Ministry of Natural Resources is spraying herbicide over forested areas across the Sudbury region.
In the next few weeks, about 2,200 hectares around Windy Lake, Wanapitei, north of Panache, southeast of Killarney Provincial Park and east of Tyson Lake will be sprayed.
The MNR said it will be spraying a herbicide called glyphosate, which is more commonly referred to as Round-Up.
The purpose is to kill the living plants to promote tree growth.
But Laurentian University biology professor Charles Ramcharan said there are concerns about the herbicide.
"It will kill just about any living plant," he said. "My biggest concern would be for amphibians ... [which] are abundant in these regions ... and they are more sensitive to all herbicides."
Ramcharan said amphibians, like frogs and newts, could end up with reproductive and developmental problems. He said there have been reports of affects on fish too.
There are also ecological effects to consider.
"Animals are dependent on those plants for food and cover," he said of the broad-spectrum herbicide. "[Glyphosate]interferes with the genetic pathway in the plant. It's very effective."
The herbicide is somewhat less effective on conifers as they have a waxy coating on the needles, protecting them from absorbing the chemicals.
Ramcharan said spraying glyphosate is a standard technique for crop forests.
"They can spray a forest and selectively preserve the conifers," he said.
But will the herbicide harm people?
Not at the recommended doses, he said.
"They are pretty safe, for humans, at the recommended doses," Ramcharam noted.
Herbicide is legal to use: MNR
All herbicides in Canada must be approved by the pest management regulatory agency, a provincial vegetation management specialist with the ministry said.
Michael Irvine said the herbicide is used on a small scale in forestry, and added it’s mostly used by farmers as it is sprayed on crops.
"So just before it’s harvested, glyphosate is applied to help dry down the crop or get rid of perennial weeds that are present," he explained.
"So you probably have things in your cupboard that have been sprayed."
Unless the government bans the herbicide, the ministry said it will likely continue to use it, he said.
"Signs will be posted at the time of application," he said.
"There will be people to prevent other people from entering those spray blocks."
The spraying is expected to last until mid-September.