On old peatlands, the peat decomposes slowly and continually releases carbon dioxide into the atmosphere. According to Natural Resources Institute Finland (LUKE), wetlands that have been retired from peat production may annually cause as much as 2,000-3,000kg of carbon dioxide emissions per hectare.
Selecting wetlands for afforestation is of paramount importance because it not only releases carbon dioxide (CO2) but also prevents the release of methane and possibly nitrous oxide. Methane (CH4) is more ephemeral than carbon dioxide, but its greenhouse effect is multifold. Nitrous oxide (N2O) has an even greater effect than methane. The soil continues to release gases until vegetation has entirely taken over the ground. If the peat layer on top of the mineral soil is thick, the ground vegetation has little chance of survival.
Without taking measures, the grassification or afforestation of peatland is heavily partial, if not non-existent. The primary goal of a carbon sink is to grow a stand of trees that absorbs carbon and therefore offsets the carbon dioxide emissions of the residual peat. Afforestation, when successful, absorbs carbon enough to offset carbon elsewhere.
We are involved in the project “Old fields and peatlands to carbon sinks”, a LUKE 2020 initiative, that focuses on this particular problem. According to LUKE the afforestation of wetlands can significantly reduce greenhouse gas emissions. In Finland, there are approximately 200,000 hectares of peatland and unused fields, which instead of storing carbon, release large quantities of carbon dioxide. It is estimated that these greenhouse gas emissions make up almost 13% of the total nationwide emissions.
Benefits of the afforestation of peatlands that are retired from peat production
The reduction of emissions to water bodies and the atmosphere from peatlands
Increase in absorbing of carbon dioxide to the biomass of trees
As a result of afforestation projects, the land area available for forestry increases and is not, for example, used for cultivation.
Natural Resources Institute Finland (LUKE) has a report on how the afforestation of wetlands affects nature and absorbs carbon dioxide.