The capacity of Finland's forests to absorb carbon dioxide from the atmosphere has doubled in the past 20 years, Finnish media reported Wednesday.

According to Finnish Forest Research Institute, Finland's forests absorb 42 million tonnes of carbon dioxide a year, which is well over half of Finnish carbon dioxide emissions, which were 70 million tonnes in 2008.

Finnish forests contain about 2.2 billion cubic meters of wood, and about 100 million a year is added through natural growth.

The growth rate means that 70 million cubic meters of wood could be felled each year without leading to a net loss. When new growth constantly exceeds what is extracted, forests turn into a carbon sink.

Growth of trees has increased the ability of Finland's forests to absorb carbon, even though construction of buildings and transport infrastructure has slightly encroached on forests.

The institute calculates that the harvesting of energy wood would not have any significant impact on sustainable felling of wood for raw materials. Energy wood mainly involves branches, treetops, stumps, and parts of the trunk that are not suitable for cooking into pulp.

In years such as 2009, when wood extraction from forests is low, energy wood would be available from the thinning of young forests. Thinning young forests could bring in up to 10 million cubic meters of energy wood.