Productivity and carbon dynamics in managed Central European forests depending on site conditions and thinning regimes

The responsibilities of modern forest practice and science in Central Europe have changed strongly within the last decades. The awareness of anthropogenic causes for the forest decline in the 1980s and for the rapid climate change has led to a new definition of sustainability in forestry which goes far beyond the traditional focus on wood volume that guided forestry in Central Europe so far (MCPFE, 1993; MCPFE, 2003a, 2003b; Hasenauer, 2004; Baumgarten and von Teuffel, 2005). One of the ‘hot’ topics of the sustainability criteria is the forest carbon budget. On global scale, the forest carbon mitigation potential is estimated to reach 0.35–1.15 Gt C year‐1 in 2030 (IPCC, 2007), which can contribute to buffer the still increasing anthropogenic CO2 emission (9.5–13.5 Gt C year‐1 in 2030; IPCC, 2007). For Germany, the second national forest inventory in 2003 (BMVEL, 2005) revealed an average volume density of 320 m3 ha‐1 (~120 t C/ha; calculation according to Baritz and Strich, 2000), and an increase in standing volume of ~20 per cent compared with the first national inventory in 1990 (only comparing values of former West Germany). Of course, the potential carbon density is limited and will certainly alter under changing climate conditions. Until the end of the 21st century, mean annual temperature in Germany will rise by 1.4–2.1°C combined with changes in precipitation of −10 to +10 per cent (SRES B1 according to Spekat et al., 2007). Along with the climate, other environmental conditions such as soil properties or immission concentrations will also change. The influence of these single and combined effects, as well as feedback reactions on the growth of trees and forest stands is not yet understood in detail, although there are a lot of studies dealing with these topics (e.g. Pretzsch and Dursky, 2002; Bergh et al., 2003; Rötzer et al., 2005; Garcia-Gonzalo et al., 2007). Forest growth models integrate a wide range of system knowledge and can calculate scenarios under different management regimes (Pretzsch et al., 2008). Reviews of these models, their use and possible fields of application can be found in Battaglia and Sands (1998), Bugmann (2001), Le Roux et al. (2001), Porte and Bartelink (2002), Monserud (2003) or Pretzsch et al. (2008). Most directly, however, the carbon sequestration potential of forests is dependent on forest management in terms of species choice and stand density regulation as well as on disturbances. As such factors cannot be tested in realtime scenarios, forest growth models are needed that predict stand development and differentiation in dependence Productivity and carbon dynamics in managed Central European forests depending on site conditions and thinning regimes