Chapter 7 - The climate mitigation potential of managed versus unmanaged spruce and beech forests in Central Europe

Abstract

The European Union (EU) has promised to cut its energy consumption by 20% by 2020. As a result, the use of petroleum products has continually decreased, and the use of renewable energy sources has increased. For the EU as a whole, however, the use of wood for energy has been fairly constant, even if its use has increased in several countries, for example, in the Nordic countries, the United Kingdom (UK), and Germany. As the consumption grows, the demands are increasingly met by imports of wood pellets, especially in countries with small forest areas such as Denmark and the UK, but also in Germany. Even if the forest area is increasing in many European countries, the land use change for urban development and nature conservation efforts have furthermore reduced the contribution of the forest sector in some countries. Given this situation, this chapter analyzed how managed and unmanaged temperate forests of the deciduous broad-leaved European beech (Fagus sylvatica) and the evergreen coniferous Norway spruce (Picea abies) species, to see how these forests can best help to mitigate climate change by storage of carbon in the forest and substitution of fossil intensive materials. The assessment was based on yield tables, wood assortment tables, deadwood and product-decay functions, and on the measured growth data from managed and unmanaged forests. All results are expressed as wood volume (m3/ha) that either store carbon or is made available for substitution through harvesting. The time frame is based on a suggested natural life cycle of unmanaged forest which is 230 years for beech and 350 years for spruce. In such time frames, the mitigation effect by storage is approximately zero for unmanaged forests, as the produced biomass is subject to natural mortality and input to deadwood pools that decompose and return the CO2 to the atmosphere.