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Sustainable Development

Fungi used to promote tree growth

There could be a day in the distant future when former mine sites are filled with large pine trees blowing in the breeze, instead of barren expanses of rock.CVRD Inco has been planting trees for 40 years as part of its internationally renowned environmental reclamation work.

Environmental engineer Quentin Smith said it would be quite difficult to return mine sites in the Sudbury area to how they were before forestry and mining began in the late 1800s and early 1900s.

However, he can see a day, perhaps 200 years in the future, when there are mature trees on abandoned mine sites.
“We have closure plans for all of our operating sites,” he said.

“That’s something we’re mandated to do by the Ministry of Northern Development and Mines. It basically states we have to return these mine sites to a natural state.”

“I have every confidence that in 200 years, the re-greening work that we’re doing will start to pay dividends. We will definitely see some mature trees. Even if you look around the tailings areas, some trees are now 40 years old. They’re not terribly large, mind you.”

In some areas, trees seem to appear on their own without any seedlings being planted.

Smith removes mine waste material like slag and replaces it with clay and earth. He then seeds the clay, and within a few years, “pioneer” trees like birch and poplar start to grow.

Hardy evergreen trees like red pine and jack pine are planted in some areas by CVRD Inco and community groups. Smith said he can remember planting trees as a child in the 1980s with his Boy Scout troop.

Seedlings

The trees are grown in a greenhouse in Copper Cliff and 4,700 feet underground in Creighton Mine, where the warm conditions incubate tree seeds quickly.

“We have a pretty good success rate with these little seedlings,” he said.

“The two tree species that we pick are red and jack pine. They are very hardy and tolerant of acidic soil conditions. We used to grow white pine and spruce as well, but we stopped because they’re not as hardy. They’re more of an ornamental species.”

Steve Dominy works for the federal government’s Great Lakes Forestry Centre in Sault Ste. Marie.

He has done research on how planting trees on unused lands could help the country reduce greenhouse gas emissions and comply with Kyoto protocol commitments.

Most of his research has focused on abandoned farmland, but he said it applies to former mine sites as well.

Under the Kyoto agreement, industries can receive credits for planting trees to make up for some of the carbon gases they expel into the air.

If this system were more developed, companies might be tempted to plant more trees on their property.

Unfortunately, carbon credit trading is still in its infancy, he said.

Trees reduce greenhouse gas emissions by taking carbon dioxide from the atmosphere. If seedlings are planted close to water, they will eventually provide shade to streams, which cools the water and makes for better fish and wildlife habitat.

“Tree roots also filter water and clean it before it gets into nearby streams and lakes,” Dominy said.

Many companies, including mining companies like CVRD Inco, are already planting trees and other vegetation without a government incentive program.

The forestry centre has also started looking at how planted forests can be harvested in the future to produce bio-energy.

“It’s not using waste from the forest, but actually going onto abandoned or under-utilized lands and planting crops for energy,” he said.

“You can make ethanol from wood, but it isn’t that cost-effective right now. We’re really focusing in on either burning the wood directly or producing a bio-oil directly from it.”

If planting trees on abandoned mine-sites and other unused lands becomes more popular, it would definitely have a positive affect on the environment, said Dominy.

Mikro-Tek

Mark Kean, the owner of Mikro-Tek, a Timmins-based environmental technology company, is also doing his share to ensure all types of plants thrive in industrial areas.

He said it’s possible there will be forests on abandoned mine sites in the future, although many challenges would have to be overcome.

“It would take some work,” said Kean.

“When you start with fresh tailings, there’s absolutely no growth on that.”

His company uses naturally-occurring soil fungi called mycorrhizae which cause trees and other plants to grow better in mine tailings, former mine sites and heavily-used agricultural soils.

The fungi allow most plants to increase moisture and nutrient uptake from the soil. In some cases, it increases plant growth and survival rates by 25 per cent.

In the 1980s, Kean owned a plant nursery in Timmins and was contracted by one of the local mines to re-green a tailings area.

“We found that there was very poor survival of trees. They didn’t grow.”

He ran across research about mycorrhizae and, in 1990, he started Mikro-Tek. Kean has worked with CVRD Inco, Xstrata Nickel, Goldcorp and at the abandoned Kamiskotia mine site near Timmins to re-green tailings.

The beneficial fungi are either coated onto the seeds themselves or introduced through irrigation. Mycorrhizae cannot survive without host plants like trees, so they aren’t normally found outside a forest.

“If you’re putting a conifer species into an area that hasn’t had conifers in the past, those mycorrhizae strains aren’t necessarily there,” said Kean.

“Mine tailings areas are basically crushed rock. There’s no organic material on the site at all. There’s no bacteria or fungi. That’s why you get a big increase in tree survival if you introduce mycorrhizae into a site that has none at all.”

www.mikro-tek.com
www.inco.com

 

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