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Springer Old Growth Forests - Chapter 11

Chapter 11 Soil Carbon Accumulation in Old-Growth Forests An area of 4.1 billion ha land is covered with boreal, temperate and tropical forest, together comprising up to 80% of the terrestrial aboveground carbon and 40% of total soil carbon | Chapter 11 Soil Carbon Accumulation in Old-Growth Forests Gerd Gleixner Cindy Tefs Albrecht Jordan Matthias Hammer Christian Wirth Angela Nueske Alexander Telz Uwe E. Schmidt and Stephan Glatzel 11.1 Introduction An area of 4.1 billion ha land is covered with boreal temperate and tropical forest together comprising up to 80 of the terrestrial aboveground carbon and 40 of total soil carbon Dixon et al. 1994 Pregitzer and Euskirchen 2004 . Forest ecosystems are well studied mainly because of their importance for timber production during the early economic development of many countries. In the context of global change however other ecosystem services like provision of drinking water or carbon sequestration have gained importance. Less is known about these. For ecosystem carbon uptake it is assumed that biomass production is highest in younger and middle-aged stands but declines with forest age Pregitzer and Euskirchen 2004 and that long-term soil carbon sequestration is very low Schlesinger 1990 . Both factors suggest that old-growth forests are close to being carbon neutral i.e. neither storing nor losing carbon. However these assumptions neglect the fact that root and leaf litter production and the accumulation of coarse woody debris might be highest in old-growth forests and that soil carbon storage might occur in deeper soil layers rather than in the more often investigated top soils. This chapter will summarise current knowledge regarding soil carbon storage identifying factors that might affect soil carbon storage in old-growth forests. Finally the first results relating to soil carbon storage from a case study in a 250-year-old beech forest will be presented. 11.2 Development of Soil Carbon Stocks in Ecosystems In the long term accumulation of soil carbon during ecosystem development is driven by the input decomposition and output of plant-derived carbon. The initial step for most carbon found in soil is autotrophic reduction of oxidised carbon from the .