Canada's boreal forest is a ticking "carbon bomb" and its continued logging could trigger a massive release of greenhouse gases, says a new report.
A Greenpeace study says cutting down trees in the boreal forest is exacerbating climate change by releasing stores of greenhouse gases (GHGs) trapped in soil and vegetation.
It also found that logging makes the forest more susceptible to insect outbreaks and wildfires which, if widespread, could cause a spike in GHG emissions - the so-called "carbon bomb."
And the report says a warmer climate melts permafrost, releasing methane, a GHG 21 times more potent than carbon dioxide.
"The idea is that if the current trends continue ... what could happen is a sudden and massive release of greenhouse gases from the forest caused by a rapid outbreak of forest or peat fires," said Greenpeace's Christy Ferguson.
Greenpeace isn't suggesting Canada halt all logging of the boreal forest, she said. The group wants the untouched parts of the forest kept that way.
The head of the Forest Products Association of Canada agrees. Avrim Lazar says the association, which represents wood, pulp and paper producers, has agreed there should be no logging in the untouched parts of the forest without adequate planning.
But he says stopping all logging is unrealistic.
"Shutting down logging of the boreal will create a huge market opportunity for the deforesters and the illegal loggers, and will have the perverse impact of trashing the boreal to increase climate change," Lazar said. "But if people aren't buying it from Canadian places, they're just going to buy it from somewhere else. If you stop harvesting from the boreal, are people going to stop using paper or wood? There's no evidence of that."
Canada's boreal forest stores 186 billion tonnes of carbon dioxide, the report says - about 27 times the world's yearly fossil-fuel emissions.
About 80 per cent of the carbon is stored in the soil as dead organic matter. The rest is stored in the forest's evergreen trees, moss and peat.
Older, untouched parts of the forest tend to store about three times more carbon than younger trees planted to replace logged ones, Ferguson said.
The boreal forest cuts a swath from Canada's Far North down to British Columbia and all the way across to the East Coast.
Most of the untouched parts of the boreal forest are located in the northern parts of Saskatchewan, Manitoba, Ontario and Quebec.
The federal government's national forestry database shows about 900,000 hectares boreal forest are logged each year.
There's some debate, however, about how much carbon is actually released through logging.
A spokeswoman for Natural Resources Minister Gary Lunn did not respond to requests for comment.