1. Pulse-labelling trees to study carbon allocation dynamics: a review of methods, current knowledge and future prospects
- Author
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Dominique Gérant, Pascale Maillard, Peter Högberg, Jukka Pumpanen, Daniel Epron, Arthur Gessler, Delphine Derrien, Michael Bahn, Masako Dannoura, Fernando A. Lattanzi, Nina Buchmann, Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Inst Ecol, University of Innsbruck, Unité de recherche Biogéochimie des Ecosystèmes Forestiers (BEF), Institut National de la Recherche Agronomique (INRA), Lehrstuhl Grunlandlehre, Alte Akad, Technical University of Munich (TUM), Forest Ecology and Management [Helsinki], Department of Forest Sciences [Helsinki], Faculty of Agriculture and Forestry [Helsinki], University of Helsinki-University of Helsinki-Faculty of Agriculture and Forestry [Helsinki], University of Helsinki-University of Helsinki, Inst Landscape Biogeochem, Leibniz-Zentrum für Agrarlandschaftsforschung = Leibniz Centre for Agricultural Landscape Research (ZALF), Fac Agr & Hort, Humboldt Universität zu Berlin, Dept Forest Ecol & Management, Swedish University of Agricultural Sciences (SLU), Grad Sch Agr, Dept Forest & Biomat Sci, Lab Forest Utilizat, Kyoto University, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), COST Action [ES0806], DFG [LA: 2390/1-1], Academy of Finland [218094], European Commission [FP7-ENV-2008-1-226701], Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Humboldt-Universität zu Berlin, Department of Forest Ecology and Management, and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)
- Subjects
0106 biological sciences ,carbon isotope ,Environmental change ,Physiology ,transfer time ,[SDV]Life Sciences [q-bio] ,Biome ,Plant Science ,Biology ,MATURE DECIDUOUS FOREST ,01 natural sciences ,HIGH TEMPORAL RESOLUTION ,Trees ,BELOW-GROUND CARBON ,forest ,03 medical and health sciences ,partitioning ,SCOTS-PINE ,Resource Acquisition Is Initialization ,Temperate climate ,medicine ,BOREAL PINE FOREST ,Photosynthesis ,Radioactive Tracers ,residence time ,RECENTLY ASSIMILATED CARBON ,030304 developmental biology ,Carbon Isotopes ,0303 health sciences ,Ecology ,Phenology ,Scots pine ,DIOXIDE ENRICHMENT FACE ,Carbon Dioxide ,15. Life on land ,Seasonality ,biology.organism_classification ,medicine.disease ,Carbon ,13. Climate action ,FAGUS-SYLVATICA L ,Soil water ,SYLVESTRIS L TREES ,SOIL CO2 EFFLUX ,010606 plant biology & botany - Abstract
Pulse-labelling of trees with stable or radioactive carbon (C) isotopes offers the unique opportunity to trace the fate of labelled CO(2) into the tree and its release to the soil and the atmosphere. Thus, pulse-labelling enables the quantification of C partitioning in forests and the assessment of the role of partitioning in tree growth, resource acquisition and C sequestration. However, this is associated with challenges as regards the choice of a tracer, the methods of tracing labelled C in tree and soil compartments and the quantitative analysis of C dynamics. Based on data from 47 studies, the rate of transfer differs between broadleaved and coniferous species and decreases as temperature and soil water content decrease. Labelled C is rapidly transferred belowground-within a few days or less-and this transfer is slowed down by drought. Half-lives of labelled C in phloem sap (transfer pool) and in mature leaves (source organs) are short, while those of sink organs (growing tissues, seasonal storage) are longer. (13)C measurements in respiratory efflux at high temporal resolution provide the best estimate of the mean residence times of C in respiratory substrate pools, and the best basis for compartmental modelling. Seasonal C dynamics and allocation patterns indicate that sink strength variations are important drivers for C fluxes. We propose a conceptual model for temperate and boreal trees, which considers the use of recently assimilated C versus stored C. We recommend best practices for designing and analysing pulse-labelling experiments, and identify several topics which we consider of prime importance for future research on C allocation in trees: (i) whole-tree C source-sink relations, (ii) C allocation to secondary metabolism, (iii) responses to environmental change, (iv) effects of seasonality versus phenology in and across biomes, and (v) carbon-nitrogen interactions. Substantial progress is expected from emerging technologies, but the largest challenge remains to carry out in situ whole-tree labelling experiments on mature trees to improve our understanding of the environmental and physiological controls on C allocation.
- Published
- 2012
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