Coppicing shifts CO2 stimulation of poplar productivity to above-ground pools: a synthesis of leaf to stand level results from the POP/EUROFACE experiment |
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| Authors: | Marion Liberloo Martin Lukac Carlo Calfapietra Marcel R. Hoosbeek Birgit Gielen Franco Miglietta Giuseppe E. Scarascia-Mugnozza Reinhart Ceulemans |
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| Affiliation: | University of Antwerp, Research Group of Plant and Vegetation Ecology, Department of Biology, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium;;NERC Centre for Population Biology, Division of Biology, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK;;University of Tuscia, DISAFRI, Via San Camillo De Lellis, I-01100 Viterbo, Italy;;National Research Council (CNR), Institute of Agro-Environmental &Forest Biology, Via Salaria km 29,300, 00015 Monterotondo Scalo (Roma), Italy;;Department of Environmental Sciences, Earth System Science –Climate Change group, Wageningen University, PO Box 47, 6700AA Wageningen, the Netherlands;;Institute of Biometeorology –National Research Council (IBIMET-CNR), Via Caproni 8, 50145 Firenze, Italy |
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| Abstract: | A poplar short rotation coppice (SRC) grown for the production of bioenergy can combine carbon (C) storage with fossil fuel substitution. Here, we summarize the responses of a poplar ( Populus ) plantation to 6 yr of free air CO2 enrichment (POP/EUROFACE consisting of two rotation cycles). We show that a poplar plantation growing in nonlimiting light, nutrient and water conditions will significantly increase its productivity in elevated CO2 concentrations ([CO2]). Increased biomass yield resulted from an early growth enhancement and photosynthesis did not acclimate to elevated [CO2]. Sufficient nutrient availability, increased nitrogen use efficiency (NUE) and the large sink capacity of poplars contributed to the sustained increase in C uptake over 6 yr. Additional C taken up in high [CO2] was mainly invested into woody biomass pools. Coppicing increased yield by 66% and partly shifted the extra C uptake in elevated [CO2] to above-ground pools, as fine root biomass declined and its [CO2] stimulation disappeared. Mineral soil C increased equally in ambient and elevated [CO2] during the 6 yr experiment. However, elevated [CO2] increased the stabilization of C in the mineral soil. Increased productivity of a poplar SRC in elevated [CO2] may allow shorter rotation cycles, enhancing the viability of SRC for biofuel production. |
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| Keywords: | carbon (C) storage elevated CO2 nutrient availability photosynthesis POP/EUROFACE Populus productivity soil |
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