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Storing carbon in forests may be harmful |
The carbon store in forests can be increased by increasing the forest area. However, in Finland this is largely impossible because the share of the forest area of total land area already is so high. The decrease of forest area in Finland is largely due to construction, while the increase is due to the transformation of agricultural land to forest. All in all, it is estimated that the forest area of Finland will decrease by 36,000 hectares in 2008–12. This represents 0.15 per cent of the total forest area of Finland.
Another way to increase the carbon store in forests is to allow the forests to develop towards a more natural state either by leaving them totally without silviculture or by increasing the rotation period of forestry.
However, this tool would work only provisionally since the carbon stores in the forest cannot grow indefinitely. As the forest reaches a natural state, the release of carbon through respiration, burning and decay will increase.
According to the researchers this option would not promote sustainable development, because it can be used only once in any given forest area. Moreover, if it is used once, it prevents the next generations from using the trees for any other purpose, because all use would lead to emissions of the carbon store. So, one would lose the option to use the forests in preventing the climate change in a sustainable and stable way – for example, in bioenergy production or increasing the carbon store in forest products.
In Finland, peatland contains even more carbon than the forests. For this reason, drainage carried out as a forestry measure also has an impact on climate change. However, first-time drainage has been abandoned in Finland with the introduction of forest certification.
The greenhouse emissions did in general increase immediately after drainage, but after a while they have decreased significantly. In addition to this, the vegetation of drained mires has increased, which has sequestered some of the released carbon. For instance, the tree stock of drained mires has doubled from the start of the drainage.
Overall, many drainage areas are returning back towards natural condition which results in more and more carbon being sequestered into the mires. Currently the carbon sink formed by drained mires sequesters some 1.9–4.5 million tons of carbon every year.
 Graphs related to forest resources
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