Climate change may benefit forestry

Not only do forests have an effect on climate change, but climate change is also likely to have an impact on forests. As to what this impact will be is difficult to assess, since the progress and consequences of climate change are not clearly known.

The International Panel on Climate Change (IPCC) has estimated that the mean temperature in Finland would rise by 1.4–5.8 degrees by the year 2100, the most likely forecast being 4.4 degrees. In southern Finland this would mean the average temperature level which now prevails in Denmark. It has also been estimated that rainfall would increase, at least in winter. The changes would have a considerable impact on forest biodiversity. The range of species and the interaction between species may change; competition, parasites and predators may alter the abundance of species. Forest pests may also spread into Finland when winter frosts no longer decimate them.

The higher temperature and atmospheric carbon dioxide could improve the growth potential of forests. This would increase the binding of carbon in the vegetation, which in its turn would slow down the change. New species of trees would not be likely to arrive in Finland very soon – at least if the principle of not planting them would still be adhered to – since the natural rate of spreading of a tree is only 10–45 kilometres per century. Moreover, the peat-dominated soil of Finland is not suitable for many southern species. The increase in the average temperature would increase the amount of atmospheric heat energy, which might lead to an increase in extreme climatic phenomena, such as storms, severe droughts and rains, severe heat and cold. However, it is difficult to assess the impact of all this on the forests.

Overall, it is likely that Finnish forestry would benefit from climate change, since the growth of trees would accelerate by up to 20–40 percent, using current forestry methods. The present tree species would remain, but southern hardwood species would spread further north, and beech would arrive as a new species. Scots pine would remain the dominant tree of arid and poor soils, but its share would go down to 20 percent. Moist heathland forests and heathland forests with grass-herb vegetation would turn into mixed forests of birch and spruce, and the share of spruce as the dominant species would go up to 60 percent. The remaining 20 percent would be taken over by birch and other deciduous trees.

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