Chapter 5 The Imprint of Species Turnover on Old-Growth Forest Carbon Balances – Insights From a Trait-Based Model of Forest Dynamics Christian Wirth and Jeremy W. Lichstein Succession is the process that eventually transforms a young forest into an oldgrowth forest. Describing and analysing plant succession has been at the core of ecology since its early days | Chapter 5 The Imprint of Species Turnover on Old-Growth Forest Carbon Balances - Insights From a Trait-Based Model of Forest Dynamics Christian Wirth and Jeremy W. Lichstein Introduction Succession is the process that eventually transforms a young forest into an old-growth forest. Describing and analysing plant succession has been at the core of ecology since its early days some hundred years ago. With respect to forest succession our understanding has progressed from descriptive classifications . identifying which forest types constitute a successional sequence to general theories of forest succession Watt 1947 Horn 1974 1981 Botkin 1981 West et al. 1981 Shugart 1984 and simulation models of forest dynamics that are capable of predicting successional pathways with remarkable precision Urban et al. 1991 Pacala et al. 1996 Shugart and Smith 1996 Badeck et al. 2001 Bugmann 2001 Hickler et al. 2004 Purves et al. 2008 . Although the importance of different factors in controlling successional changes in species composition is still debated particularly in speciose tropical forests Hubbell 2001 a large body of evidence implicates the tradeoff between shadetolerance and high-light growth rate as a key driver Bazzaz 1979 Pacala et al. 1994 Wright et al. 2003 . In contrast there is no well-accepted mechanism to explain successional changes in forest biomass much less other components of ecosystem carbon. A range of biomass trajectories have been observed . monotonic vs hump-shaped curves and some basic ideas have been proposed to explain these patterns Peet 1981 1992 Shugart 1984 . However we are aware of only one systematic geographically extensive assessment of biomass trajectories see Chap. 14 by Lichstein et al. this volume . In this data vacuum it has been difficult to assess the relative merits of different theories or mechanisms. This is especially true for later stages of forest succession and in particular for old-growth forests. With respect to biomass .
