Canada’s carbon sink has sprung a leak
Until recently, its vast forests vacuumed up carbon dioxide. Now that process has been thrown in reverse.
(Page 2 of 2)
How enormous? Perhaps the most overlooked piece of the puzzle may be that cutting forest canopy could release massive amounts of CO2 contained in yards-thick peat bogs that lie beneath the boreal. That peat layer is not only a “carbon bank,” but potentially a “carbon bomb,” some say.Skip to next paragraph
Subscribe Today to the Monitor
David Schindler, professor of ecology at the University of Alberta, is among a number of scientists worried that cutting the forest faster could vastly accelerate global warming by causing the peat layer to dry out, decay, and release CO2 – or to burn in wildfires.
“A lot of people are fooled because the trees don’t seem very large,” Professor Schindler says. “They don’t realize there’s as much carbon stored in the forest floor as in the Amazon. That ‘carbon bomb,’ as some call it, is a real concern.”
The Canadian forest industry in 2007 responded to increased beetle- and fire-killed timber by increasing harvest rates, the CFS reported last year. Given that much of the boreal may live less than a century, the Ontario Forest Research Institute found “sustainable forest management and use of wood products helps to mitigate climate change.”
“Sustainable” is open to debate.
Some 70 percent of the nation’s managed forest – and much of the boreal – is certified by third parties as “sustainably managed,” the Forest Products Association of Canada reports. All land managed by FPAC members is certified sustainable and the group touts its investments in energy efficiency.
That doesn’t impress Peter Lee of Global Forest Watch Canada.
“It’s clear to me that the managed part of the forest is contributing to the forest turning into a carbon source,” Mr. Lee says. “The more heavily you manage for logging and industrial activity, the more these forests become a source of atmospheric carbon.”
But as long as global demand exists for wood products, “very few sources are as carefully managed as ours,” counters Avrim Lazar, president of FPAC. “The real question is: If you didn’t get [wood] from the [Canadian] boreal, where would it come from?’ ”
One answer: from illegal logging activities in Russia’s hard-pressed boreal forest – which contains half the world’s boreal, he says. FPAC, he points out, supported the Ontario government’s move last year to put 55 million acres, about one-quarter of the provincial forest, off limits to logging.
In the end, what is truly sustainable may hinge on a hotly debated issue: How much carbon is stored – and for how long – in wood products like homes, furniture, and paper? Wood framing for homes can prevent release of carbon into the atmosphere for as long or perhaps longer than forests themselves, the study says.
Product disposal is critical factor
“If the stuff ends up in landfill, then it comes back as methane which destroys us completely on the cycle,” Mr. Lazar says. Airless landfills promote the production of methane as a byproduct of decomposition. As a greenhouse gas, methane is ten times as potent as carbon dioxide.
“Really, the critical factor on whether forestry has a positive or negative impact on greenhouse gases is management of the product at the end of the life cycle.”
But with much of Canada’s logging going to produce paper, the carbon content of which is released back into the air in just a few years, environmentalists say more detailed life cycle analyses of wood-product carbon is required. Researchers are looking into such things as the impact longer logging roads would have on emissions from logging trucks driving further.
Such issues may inevitably become part of the debate at the coming climate summit in Copenhagen this December. But Andrew Park, an assistant professor at the Center for Forest Interdisciplinary Research at the University of Winnipeg, is circumspect about the impact of less or more logging on greenhouse-gas emissions.
“Our vast territory and the variability in disturbance ... means that we will never be able to control whether the boreal forest as a whole acts as a source or a sink,” he writes in an e-mail.
To ensure that the boreal forest continues to act as a globally important carbon sink, he writes, “we need to limit the warming that is underway. Not to do so is to risk losing the billions of tons of carbon stored in peat and permafrost.”