4.3.3. Climate change

Forests bind a considerable amount of carbon, which, as the forests are destroyed, is released to the atmosphere, worsening the greenhouse effect. The destruction and structural change of the tropical rainforests has been estimated to account for around 20-25 % of the global increase of the greenhouse effect. Most of this is due to the carbon dioxide which is released, but nitrous oxide (N2O, a greenhouse gas) is also released through the large-scale addition of artificial fertilisers to the plantations (Houghton, 1995).

UPM-Kymmene has advertised the plantations as being carbon sinks, which, during their growing phase, store carbon dioxide that would otherwise be contributing to the greenhouse effect. This carbon, however, is re-released at the latest when the paper it has been turned into decomposes. Due to the short life span of the paper product, the bound carbon is soon re-released. What is of more importance is the amount of carbon that is permanently bound in the forest. In theory, planted forests can bind as much carbon as natural forests, but in practice the continuous logging and planting of seedlings keep the average bound carbon of a plantation at a much lower level than that of a natural forest (i.e. about 1/3 - 1/2 of that of a natural forest). It has to be kept in mind, though, that many of the forests converted by APRIL had previously been logged selectively. Regardless of this, their carbon-binding capacity is higher than that of the plantations. According to one estimate, the amount of biomass in treated forests is about 60 % of that found in natural, untouched forests (Flint et al., 1994).