Plumbing the depths of Canada’s peatlands – one of the world’s largest carbon sinks

Discussion about climate change often centres on carbon dioxide being released into the atmosphere. We hear less about carbon sinks – things that store more carbon than they release.

The Amazon rainforest and ocean plankton are important carbon sinks.  But there is a lesser-known, and increasingly important sink that is capturing the attention of scientists. It is the wetlands of Canada’s boreal forest.

Scientists are conducting research to quantify the carbon-storing potential of peatlands. These are types of wetland systems made up of bogs and fens. The Geological Survey of Canada says peat in Canada’s wetlands stores almost 60 percent of all carbon stored in soils across the country.

“With peatlands, we can be talking about several millennia of accumulated organic material that maintains a very slow rate of decomposition,” says Alain Richard, Head of Boreal Conservation Partnerships and Services for DUC. “Because of that, it is accumulating more carbon than decomposing, resulting in these wetland types functioning as a net carbon sink.”

Peatlands can be 40 centimetres to several metres deep. They are in a variety of places, including areas with permafrost which remain frozen all year.

“When peatland systems remain wet, cool or frozen, it really reduces the rate of organic decomposition, resulting in a net annual accumulation of carbon being stored and thereby functioning as carbon sinks,” says Richard. “But if peatlands start to dry up or permafrost starts to melt, these systems are vulnerable to becoming a source of carbon where these and other greenhouse gases are emitted to the atmosphere.”

Forest managers taking holistic approach

It’s crucial that land managers understand how much carbon is stored both in trees and soil. “Today, methods and tools for carbon measurement are well established for upland forests. These types of dry forests have been studied for decades,” says Mark Johnston, a senior research scientist at the Saskatchewan Research Council. “By comparison, we know much less about carbon measurement in wetlands, where trees are smaller and areas are water saturated and difficult to operate in.”

Developing practical methods for quantifying carbon storage in upland boreal forests and wetlands is the goal of a three-year initiative led by the Saskatchewan Research Council in collaboration with DUC’s Boreal Program, the Sustainable Forestry Initiative, Louisiana-Pacific Canada Ltd. and Spruce Products Ltd.

Forest managers are now taking a more holistic, ecosystem-based, view of their landscapes. They need to know how wetlands and uplands are related, and how forestry activities can affect wetland values and functions such as carbon storage, says Johnston.

The goal of the project is to develop a rapid protocol that forestry professionals can use to get credible estimates of carbon storage in wetlands. Included in the work are field tests with Louisiana-Pacific Canada Ltd. and Spruce Products Ltd. near Swan River, Manitoba. Field work began last summer with workers taking measurements of peat depth.

The Sustainable Forestry Initiative is supporting the project through its Conservation Grants Program. Louisiana-Pacific and Spruce Products have provided access and resources on the forest areas they manage. Ducks Unlimited Canada has mapped the wetlands in the area under study and has used this information to select the wetland sample sites for the study. This wetland mapping captures the type and density of vegetation, and identifies different types of wetlands, including those with deep peat deposits. This will allow for more accurate estimation and mapping of boreal wetland carbon stores.