Blog Posts Lauri Sikanen Climate, Forestry

Some while ago, opinions in social media were divided between whether Canadian forests are carbon sinks or carbon sources. A surprisingly large number of active Twitter users did not accept the news published widely in Canadian media services that Canada’s forests are regarded as sources of carbon dioxide.  To get to the bottom of this, we need a more thorough background study than just a few Tweets.

The largest problems in Canada’s massive forest regions are extensive forest fires, the number of which shows great variation from one year to the next. Insects also cause extensive damages, which are easier to forecast. A tree attacked by insects dies standing up, and its ability to sequester carbon stops.  When decaying, the tree releases carbon dioxide into the atmosphere. Large areas with dead trees also increase the forest fire risk.

Werner Kurz, PhD and senior research scientist at the Canadian Forest Service, focusing on forest carbon monitoring, accounting and reporting, is the leading expert in the carbon dynamics of Canada’s forests. Recently, he also gave a lecture on the subject in Finland. In his lecture, he described the development of carbon sequestration in managed forests in Canada from the 1990s to the present. The situation is clear: Canada’s managed forests have primarily been a source of carbon dioxide for the last 30 years. Emission volumes have roughly equalled the volume of carbon sequestered in Finland’s forests.

If the impact of harvesting and natural damage is excluded from the calculations, Canada’s forests would be carbon sinks. However, it is interesting to examine the size of carbon sinks relative to the size of the country.

Finland’s forests sequester carbon in reality – Canada’s forests only in theory

The theoretical carbon sequestration capacity of Canada’s managed forests is estimated to be roughly 300 million metric tons of carbon dioxide equivalent (CO2e) per year. The area of managed forests is approximately 347,000,000 hectares*. This means that, theoretically, Canada’s maximum carbon sequestration capacity would be slightly less than one tonne per hectare (0.86).

In Finland, forest carbon sequestration has been 17 million metric tons of CO2e per year at its lowest during the 2000s (in 2018). Finland’s forest area (20,300,000 hectares) is roughly six per cent of Canada’s forest area. In 2018, the corresponding actual carbon sequestration capacity per hectare in Finland, after harvesting and natural damage, was roughly equal to Canada’s maximum theoretical carbon sequestration capacity (0.83).

In the National Inventory Report (NIR), Canada’s forests are reported to sequester approximately 30 metric tons of CO2e of carbon per year (LULUCF and NIR do not require natural damage to be calculated in full). This would be 0.09 metric tons of CO2e per hectare per year, comprising roughly one tenth of Finland’s corresponding figure. In reality, however, Canada’s forests release more carbon dioxide than they bind, when forest damage is taken into account.

Canada’s unmanaged forests and forests in their natural state difficult to compare with Finland’s forests

Is the situation with Canada’s forests bad? Rather, the situation is quite normal regarding boreal forests that are largely unmanaged and in their natural state. Thinning is not usually carried out in Canada, apart from Quebec and the Maritimes region, where thinning volumes are also small. If any seedling stands are planted, they are not tended. The volume of dead trees in forests is sky-high. Decaying trees increase not only biodiversity, but also the risk of forest fires.

Forestry activities in Canada and Finland are so different that any comparison between the two is difficult, but also enlightening. Canada’s managed forests cover 65 per cent of the total forest land. These forests are inventoried and tended for the needs of forestry, while they also include large peatlands, national parks, forests intended for recreational use and protected forests in urban areas.

Due to long distances and the lack of a proper road network, large parts of Canada’s forests are fully in their natural state.  These areas are too distant from everywhere, and they cannot be used for similar forestry activities as in Finland. Furthermore, putting out forest fires is extremely difficult and expensive.

One possibility is to shift to the Finnish model of forest management in certain easily accessible regions in Canada, with thinning, for example, being one possible measure. Thinning and a good road network would provide forest industries with wood from new regions and reduce the risk of insect damage. At the same time, they would reduce fire loads in forests and make it easier to control forest fires. For towns and cities surrounded by forests and struggling with major fires, this would be a highly welcome situation.

Canada’s forests still have large volumes of carbon in storage

More carbon is sequestered in forests in many parts of Canada than in Finland, as Canada’s forests are not thinned and not all distant forests are harvested. This comparison leans towards Canada, also in terms of the average volume per hectare. According to the official State of Canada’s Forests report, Canada has roughly 135 cubic metres of trees per hectare, while the corresponding figure is 123 in Finland. There are so many uncertainties in estimating the volume of soil carbon sequestration that the wisest course of action is to leave it for future consideration. For the climate, it is unfortunate that Canada’s forests release more carbon dioxide into the atmosphere than what they bind. In Finland, the situation is just the opposite.

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