BG Biogeosciences BG Biogeosciences 1726-4189 Copernicus Publications Göttingen, Germany 10.5194/bg-4-125-2007 Soils apart from equilibrium – consequences for soil carbon balance modelling Wutzler T. 1 Reichstein M. 1 Max Planck Institute for Biogeochemistry, Jena, Germany 15 02 2007 4 1 125 136 Copyright: © 2007 T. Wutzler 2007 This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic License. To view a copy of this licence, visit https://creativecommons.org/licenses/by-nc-sa/2.5/ This article is available from https://bg.copernicus.org/articles/4/125/2007/bg-4-125-2007.html The full text article is available as a PDF file from https://bg.copernicus.org/articles/4/125/2007/bg-4-125-2007.pdf

Many projections of the soil carbon sink or source are based on kinetically defined carbon pool models. Para\-meters of these models are often determined in a way that the steady state of the model matches observed carbon stocks. The underlying simplifying assumption is that observed carbon stocks are near equilibrium. This assumption is challenged by observations of very old soils that do still accumulate carbon. In this modelling study we explored the consequences of the case where soils are apart from equilibrium. Calculation of equilibrium states of soils that are currently accumulating small amounts of carbon were performed using the Yasso model. It was found that already very small current accumulation rates cause big changes in theoretical equilibrium stocks, which can virtually approach infinity. We conclude that soils that have been disturbed several centuries ago are not in equilibrium but in a transient state because of the slowly ongoing accumulation of the slowest pool. A first consequence is that model calibrations to current carbon stocks that assume equilibrium state, overestimate the decay rate of the slowest pool. A second consequence is that spin-up runs (simulations until equilibrium) overestimate stocks of recently disturbed sites. In order to account for these consequences, we propose a transient correction. This correction prescribes a lower decay rate of the slowest pool and accounts for disturbances in the past by decreasing the spin-up-run predicted stocks to match an independent estimate of current soil carbon stocks. Application of this transient correction at a Central European beech forest site with a typical disturbance history resulted in an additional carbon fixation of 5.7±1.5 tC/ha within 100 years. Carbon storage capacity of disturbed forest soils is potentially much higher than currently assumed. Simulations that do not adequately account for the transient state of soil carbon stocks neglect a considerable amount of current carbon accumulation.

 References Ågren, G. I.: Temperature dependence of old soil organic matter, Ambio, 29, 55–55, 2000. Ågren, G. I., Hyvönen, R., and Nilsson, T.: Are Swedish forest soils sinks or sources for CO2 – model analyses based on forest inventory data, Biogeochemistry, in press (online first), https://doi.org/10.1007/s10533-006-9064-0, 2007. Baritz, R., De Neve, S., Brancikova, G., Gronlund, A., Leifeld, J., Katzensteiner, K., Koch, H. J., Palliere, C., Romanya, J., and Schaminee, J.: Task Group 5 – Land Use Practices and Soil Organic Matter, in: Reports of the Technical Working Groups established under the Thematic Strategy for Soil Protection. Volume 2 Soil Organic Matter Decline, edited by: Van-Camp, L., Bujarrabal, B., Gentile, A. R., Jones, R. J. A., Montanarella, L., Olazabal, C., and Selvaradjou, S.-K., Office for Official Publications of the European Communities, Luxembourg, 2004. Berg, B., De Santo, A. V., Rutigliano, F. A., Fierro, A., and Ekbohm, G.: Limit values for plant litter decomposing in two contrasting soils – influence of litter elemental composition, Acta Oecologica-International J. Ecology, 24, 295–302, 2003. Berg, B., Ekbohm, G., Johansson, M. B., McClaugherty, C., Rutigliano, F., and DeSanto, A. V.: Maximum decomposition limits of forest litter types: A synthesis, Canadian Journal of Botany-Revue Canadienne De Botanique, 74, 659–672, 1996. Berg, B. and McClaugherty, C.: Plant Litter Decomposition, Humus Formation, Carbon Sequestration, Springer, Heidelberg, 2003. Berger, T. W., Neubauer, C., and Glatzel, G.: Factors controlling soil carbon and nitrogen stores in pure stands of Norway spruce (Picea abies) and mixed species stands in Austria, For. Ecol. Manage., 159, 3–14, 2002. Caspersen, J. P., Pacala, S. W., Jenkins, J. C., Hurtt, G. C., Moorcroft, P. R., and Birdsey, R. A.: Contributions of land-use history to carbon accumulation in US forests, Science, 290, 1148–1151, 2000. Chertov, O. G., Komarov, A. S., Nadporozhskaya, M., Bykhovets, S. S., and Zudin, S. L.: ROMUL – a model of forest soil organic matter dynamics as a substantial tool for forest ecosystem modeling, Ecological Modelling, 138, 289–308, 2001. Couteaux, M. M., Berg, B., and Rovira, P.: Near infrared reflectance spectroscopy for determination of organic matter fractions including microbial biomass in coniferous forest soils, Soil Biol. Biochemistry, 35, 1587–1600, 2003. Couteaux, M. M., Bottner, P., and Berg, B.: Litter decomposition, climate and litter quality, Trends in Ecology & Evolution, 10, 63–66, 1995. Davidson, E. A. and Janssens, I. A.: Temperature sensitivity of soil carbon decomposition and feedbacks to climate change, Nature, 440, 165–173, 2006. Dittmar, O., Knapp, E., and Lembcke, G.: DDR Buchenertragstafel 1983, IFE-Berichte aus Forschung und Entwicklung, 4, 1–59, 1986. Drexhage, M. and Gruber, F.: Architecture of the skeletal root system of 40-year-old Picea abies on strongly acidified soils in the Harz Mountains (Germany), Canadian Journal of Forest Research-Revue Canadienne De Recherche Forestiere, 28, 13–22, 1998. Dupouey, J. L., Dambrine, E., Laffite, J. D., and Moares, C.: Irreversible impact of past land use on forest soils and biodiversity, Ecology, 83, 2978–2984, 2002. Falloon, P., Smith, P., Coleman, K., and Marshall, S.: Estimating the size of the inert organic matter pool from total soil organic carbon content for use in the Rothamsted carbon model, Soil Biol. Biochemistry, 30, 1207–1211, 1998. Fontaine, S. and Barot, S.: Size and functional diversity of microbe populations control plant persistence and long-term soil carbon accumulation, Ecology Lett., 8, 1075–1087, 2005. Foster, D., Swanson, F., Aber, J., Burke, I., Brokaw, N., Tilman, D., and Knapp, A.: The importance of land-use legacies to ecology and conservation, Bioscience, 53, 77–88, 2003. Goodale, C. L. and Aber, J. D.: The long-term effects of land-use history on nitrogen cycling in northern hardwood forests, Ecol. Applications, 11, 253–267, 2001. Grandy, A. S. and Robertson, G. P.: Aggregation and organic matter protection following tillage of a previously uncultivated soil, Soil Sci. Soc. Am. J., 70, 1398–1406, 2006. Harmon, M. E., Bible, K., Ryan, M. G., Shaw, D. C., Chen, H., Klopatek, J., and Li, X.: Production, respiration, and overall carbon balance in an old-growth Pseudotsuga-tsuga forest ecosystem, Ecosystems, 7, 498–512, 2004. Hedges, J. I., Keil, R. G., and Benner, R.: What happens to terrestrial organic matter in the ocean?, Organic Geochemistry, 27, 195–212, 1997. Howard, P. J. A. and Howard, D. M.: Microbial decomposition of tree and shrub leaf litter. 1. Weight loss and chemical composition of decomposing litter., Oikos, 25, 311–352, 1974. Janssens, I. A., Lankreijer, H., Matteucci, G., Kowalski, A. S., Buchmann, N., Epron, D., Pilegaard, K., Kutsch, W., Longdoz, B., Grunwald, T., Montagnani, L., Dore, S., Rebmann, C., Moors, E. J., Grelle, A., Rannik, U., Morgenstern, K., Oltchev, S., Clement, R., Gudmundsson, J., Minerbi, S., Berbigier, P., Ibrom, A., Moncrieff, J., Aubinet, M., Bernhofer, C., Jensen, N. O., Vesala, T., Granier, A., Schulze, E.-D., Lindroth, A., Dolman, A. J., Jarvis, P. G., Ceulemans, R., and Valentini, R.: Productivity overshadows temperature in determining soil and ecosystem respiration across European forests, Global Change Biol., 7, 269–278, 2001. Jansson, P.-E. and Karlberg, L.: Coupled heat and mass transfer model for soil-plant-atmosphere systems, Royal Institute of Technolgy, Dept of Civl and Environmental Engineering, Stockholm, 2004. Jenkinson, D. S.: The Turnover of Organic-Carbon and Nitrogen in Soil, Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 329, 361–368, 1990. Kaipainen, T., Liski, J., Pussinen, A., and Karjalainen, T.: Managing carbon sinks by changing rotation length in European forests, Environ. Sci. Policy, 7, 205–219, 2004. Koerner, W., Dambrine, E., Dupouey, J. L., and Benoit, M.: delta N-15 of forest soil and understorey vegetation reflect the former agricultural land use, Oecologia, 121, 421–425, 1999. Koerner, W., Dupouey, J. L., Dambrine, E., and Benoit, M.: Influence of past land use on the vegetation and soils of present day forest in the Vosges mountains, France, J. Ecology, 85, 351–358, 1997. Kummetz, E.: Die Wurzelentwicklung der Fichte (\textitPicea abies [L.] Karst.). Universität Bayreuth, Bayreuth, 1996. Le Goff, N. and Ottorini, J. M.: Root biomass and biomass increment in a beech (Fagus sylvatica L.) stand in North-East France, Ann. For. Sci., 58, 1–13, 2001. Lindner, M., Lucht, W., Bouriaud, O., Green, T., and Janssens, I. A.: Specific Study on Forest Greenhouse Gas Budget, Concerted Action CarboEurope-GHG, 2004. Liski, J., Lehtonen, A., Palosuo, T., Peltoniemi, M., Eggers, T., Muukkonen, P., and Makipaa, R.: Carbon accumulation in Finland's forests 1922–2004 – an estimate obtained by combination of forest inventory data with modelling of biomass, litter and soil, Ann. For. Sci., 63, 687–697, 2006. Liski, J., Palosuo, T., Peltoniemi, M., and Sievanen, R.: Carbon and decomposition model Yasso for forest soils, Ecological Modelling, 189, 168–182, 2005. Liski, J., Perruchoud, D., and Karjalainen, T.: Increasing carbon stocks in the forest soils of western Europe, Forest Ecology and Management, 169, 159–175, 2002. Liski, J. and Westman, C. J.: Carbon storage in forest soil of Finland .2. Size and regional patterns, Biogeochemistry, 36, 261–274, 1997. Martel, Y. A. and Paul, E. A.: Use of Radiocarbon Dating of Organic-Matter in Study of Soil Genesis, Soil Sci. Soc. Am. J., 38, 501–506, 1974. Mikutta, R., Kleber, M., Torn, M. S., and Jahn, R.: Stabilization of soil organic matter: Association with minerals or chemical recalcitrance?, Biogeochemistry, 77, 25–56, 2006. Mund, M.: Carbon pools European beech forests (\textitFagus sylvatica) under different silvicultural management, University Göttingen, Göttingen, 2004. Mund, M. and Schulze, E.-D.: Silviculture and its interactions with biodiversity and the carbon balance of forest soils, in: Forest diversity and function: temperate and boreal Systems, edited by: Scherer-Lorenzen, M., Körner, C., and Schulze, E.-D., Springer, Berlin Heildelberg New York, 2005. Nabuurs, G. J. and Schelhaas, M. J.: Carbon profiles of forests across Europe, an application of co2fix., Ecological Indicators, 1, 213–223, 2002. Palosuo, T., Liski, J., Trofymow, J. A., and Titus, B. D.: Litter decomposition affected by climate and litter quality – Testing the Yasso model with litterbag data from the Canadian intersite decomposition experiment, Ecological Modelling, 189, 183–198, 2005. Parker, J. L., Fernandez, I. J., Rustad, L. E., and Norton, S. A.: Effects of nitrogen enrichment, wildfire, and harvesting on forest-soil carbon and nitrogen, Soil Sci. Soc. Am. J., 65, 1248–1255, 2001. Parton, W. J., Stewart, J. W. B., and Cole, C. V.: Dynamics of C, N, P and S in Grassland Soils – a Model, Biogeochemistry, 5, 109–131, 1988. Peltoniemi, M., Makipaa, R., Liski, J., and Tamminen, P.: Changes in soil carbon with stand age – an evaluation of a modelling method with empirical data, Global Change Biology, 10, 2078–2091, 2004. Perruchoud, D., Walthert, L., Zimmermann, S., and Luscher, P.: Contemporary carbon stocks of mineral forest soils in the Swiss Alps, Biogeochemistry, 50, 111–136, 2000. Polyakov, V. and Lal, R.: Modeling soil organic matter dynamics as affected by soil water erosion, Environ. Int., 30, 547–556, 2004. Rothe, A., Kreutzer, K., and Kuchenhoff, H.: Influence of tree species composition on soil and soil solution properties in two mixed spruce-beech stands with contrasting history in Southern Germany, Plant and Soil, 240, 47–56, 2002. Rumpel, C., Kogel-Knabner, I., and Bruhn, F.: Vertical distribution, age, and chemical composition of organic, carbon in two forest soils of different pedogenesis, Organic Geochemistry, 33, 1131–1142, 2002. Schröter, D., Acosta-Michlik, L., Arnell, A. W., Ara\'ujo, M. B., Badeck, F., Bakker, M., Bondeau, A., Bugmann, H., Carter, T., de la Vega-Leinert, A. C., Erhard, M., Espiñeira, G. Z., Ewert, F., Fritsch, U., Friedlingstein, P., Glendining, M., Gracia, C. A., Hickler, T., House, J., Hulme, M., Kankaanpää, S., Klein, R. J. T., Krukenberg, B., Lavorel, S., Leemans, R., Lindner, M., Liski, J., Metzger, M. J., Meyer, J., Mitchell, T., Mohren, F., Morales, P., Moreno, J. M., Reginster, I., Reidsma, P., Rounsevell, M., Pla, E., Pluimers, J., Prentice, I. C., Pussinen, A., Sánchez, A., Sabaté, S., Sitch, S., Smith, B., Smith, J., Smith, P., Sykes, M. T., Thonicke, K., Thuiller, W., Tuck, G., van der Werf, G., Vayreda, J., Wattenbach, M., Wilson, D. W., Woodward, F. I., Zaehle, S., Zierl, B., Zudin, S., and Cramer, W.: ATEAM Final report 2004, Potsdam Institute for Climate Impact Research, Potsdam, Germany, 2004. Smith, J., Smith, P., Wattenbach, M., Zaehle, S., Hiederer, R., Jones, R. J. A., Montanarella, L., Rounsevell, M. D. A., Reginster, I., and Ewert, F.: Projected changes in mineral soil carbon of European croplands and grasslands, 1990–2080, Global Change Biology, 11, 2141–2152, 2005. Smith, P., Smith, J. U., Powlson, D. S., McGill, W. B., Arah, J. R. M., Chertov, O. G., Coleman, K., Franko, U., Frolking, S., Jenkinson, D. S., Jensen, L. S., Kelly, R. H., Klein-Gunnewiek, H., Komarov, A. S., Li, C., Molina, J. A. E., Mueller, T., Parton, W. J., Thornley, J. H. M., and Whitmore, A. P.: A comparison of the performance of nine soil organic matter models using datasets from seven long-term experiments, Geoderma, 81, 153–225, 1997. Thornton, P.: Description of a numerical simulation model for predicting the dynamics of energy, water, carbon, and nitrogen in a terrestrial ecosystem, 1998. Thornton, P. E., Law, B. E., Gholz, H. L., Clark, K. L., Falge, E., Ellsworth, D. S., Golstein, A. H., Monson, R. K., Hollinger, D., Falk, M., Chen, J., and Sparks, J. P.: Modeling and measuring the effects of disturbance history and climate on carbon and water budgets in evergreen needleleaf forests, Agricul. For. Meteorol., 113, 185–222, 2002. von Lützow, M., Kogel-Knabner, I., Ekschmitt, K., Matzner, E., Guggenberger, G., Marschner, B., and Flessa, H.: Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions – a review, European J. Soil Sci., 57, 426–445, 2006. Wall, A. and Hytonen, J.: Soil fertility of afforested arable land compared to continuously forested sites, Plant and Soil, 275, 247–260, 2005. Wardle, D. A., Hornberg, G., Zackrisson, O., Kalela-Brundin, M., and Coomes, D. A.: Long-term effects of wildfire on ecosystem properties across an island area gradient, Science, 300, 972–975, 2003. Wardle, D. A., Zackrisson, O., Hornberg, G., and Gallet, C.: The influence of island area on ecosystem properties, Science, 277, 1296–1299, 1997. Weiss, P., Schieler, K., Schadauer, K., Radunsky, K., and Englisch, M.: Die Kohlenstoffbilanz des österreichischen Waldes und Betrachtungen zum Kyoto-Protokoll (The carbon balance of the Austrian forest and considerations in view of the Kyoto-protocol), Umweltbundesamt, Vienna, Austria, 2000. Wirth, C., Schulze, E.-D., Schwalbe, G., Tomczyk, S., Weber, G., and Weller, E.: Dynamik der Kohlenstoffvorräte in den Wäldern Thüringens- Abschlussbericht zur 1, Phase des BMBF-Projektes "Modelluntersuchung zu Umsetzung des Kyoto-Protokolls", Thüringer Landesanstalt für Jagd, Wald und Fischerei, Jena Gotha, 2004. Wutzler, T., Köstner, B., and Bernhofer, C.: Spatially Explicit Assessment of Carbon Stocks of a Managed Forest Area in Eastern Germany, J. European For. Res., online first, https://doi.org/10.1007/s10342-006-0155-1, 2006. Zimmermann, M., Leifeld, J., and Fuhrer, J.: Quantifying soil organic carbon fractions by infrared-spectroscopy, Soil Biology and Biochemistry, 39, 224–231, 2007.