Growing forests (i.e. forests where trees are replaced at a rate greater than their harvest) are good to help mitigating climate change. A recent study has shown that the need for ever-growing areas of European forests to be conserved for bio-diversity reasons, together with the demand for end-timber products, has led to such effective forest management that today's European forests are actually increasing in value for their potential to capture carbon.
These forests produce a greater yield of wood per hectare and thus increasingly absorb more CO2 from the atmosphere per hectare. This carbon is then retained within the tree and its future wood pulp products, such as the beverage carton, for the whole life of the product. If the fibres are later recycled into new products, the carbon is locked in for even longer.
Responsible forest management practices (e.g. soil preparation, selecting the right regeneration method, cleaning of the young stands, timely thinning) mean that the yield per hectare is greater in a managed than an unmanaged forest, thus augmenting the carbon sink capacity.
Disturbances (for example fire or insects) can have impact on the forest's carbon balance, which can cause the CO2 to be released from the tree. Managed protection against wild fires and insect infestation can help keep the CO2 locked within the tree as it is able to grow older.
Trees absorb CO2 in order to grow through a process called photosynthesis. This is where the trees combine CO2, water and light to make fibre and fruits and build stores of energy. It is during this process that they release oxygen and this is the reason why forests are called the 'lungs of the earth'. The more trees grow, the more CO2 is absorbed. Young forests, in particular, need a lot of carbon as they grow.
Remarkably, while the overall area of forest in Finland has remained largely unchanged between 1912 and 2005, the forests have increased in value in the fight against climate change due to increases in the average tree size and stocking density. This co-benefit of managed forestry, motivated by the commercial need to increase timber yields, has led to an increased biomass stock in Finnish forests sequestering 18 tons of CO2 annually per km², versus CO2 emissions in the same region of 12 tons per km².
On a European scale, it is estimated that from 1990 to 2005 expanding forest biomass in the EU27 sequestered 360–495 million tonnes of CO2 from the atmosphere each year – corresponding to 8-10 per cent of the EU's fossil fuel carbon dioxide emissions.