Conservationists are raising alarm about an old growth forest northeast of Sudbury that could soon lose its protected status.

The Ontario Ministry of Natural Resources is looking at opening up a section of the Wolf Lake Forest Reserve in the interests of mineral exploration.

Ontario created the Wolf Lake Forest Reserve 12 years ago. The reserve was declared off limits to forestry companies, but mining exploration companies with existing claims in area were allowed to keep them.

The intention was to turn any lapsed mining claims into provincial parkland.

Now, the Ministry of Natural Resources is proposing to open up 340 hectares of the reserve to further mineral exploration. Minister Michael Gravelle says commercial logging would still be prohibited.

"We are very conscious, particularly in northern Ontario of the need to leave the opportunities for economic development and job creation open," Gravelle said. "We are also very very conscious of the need to protect special forests like this. That's what this is all about. It's about trying to find that balance."

Gravelle says 2,000 hectares are being added to the nearby Chiniguchi Waterway Provincial park.

Ontario's Environmental Commissioner Gord Miller says the province is backing down to industry interests.

"They're basically surrendering saying they're going to find some other lands to substitute. Well, these are unique forests, identified by them years ago, so that's just not good enough," he said.

Peter Quinby, an environmental consultant in North Bay who has studied old growth forests, says the Wolf Lake old growth red pine forest is likely the largest in North America.

"My guess is that the people of Sudbury have no idea what an ecological gem they have in their backyard," Quinby said.