Increased Litter Build Up and Soil Organic Matter Stabilization in a Poplar Plantation After 6 Years of atmospheric CO2 Enrichment (FACE): Final Results of POP-EuroFace Compared to Other Forest FACE Experiments
Hoosbeek, M.R. ; Scarascia-Mugnozza, G. - \ 2009
Ecosystems 12 (2009)2. - ISSN 1432-9840 - p. 220 - 239.
nitrogen-use efficiency - elevated co2 - carbon storage - mineral soil - terrestrial ecosystems - biomass production - cultivated soils - tropospheric o-3 - deciduous forest - n-fertilization
Free air CO2 enrichment (FACE) experiments in aggrading temperate forests and plantations have been initiated to test whether temperate forest ecosystems act as sinks for anthropogenic emissions of CO2. These FACE experiments have demonstrated increases in net primary production and carbon (C) storage in forest vegetation due to increased atmospheric CO2 concentrations. However, the fate of this extra biomass in the forest floor or mineral soil is less clear. After 6 years of FACE treatment in a short-rotation poplar plantation, we observed an additional sink of 32 g C m¿2 y¿1 in the forest floor. Mineral soil C content increased equally under ambient and increased CO2 treatment during the 6-year experiment. However, during the first half of the experiment the increase in soil C was suppressed under FACE due to a priming effect, that is, the additional labile C increased the mineralization of older SOM, whereas during the second half of the experiment the increase in soil C was larger under FACE. An additional sink of 54 g C m¿2 y¿1 in the top 10 cm of the mineral soil was created under FACE during the second half of the experiment. Although, this FACE effect was not significant due to a combination of soil spatial variability and the low number of replicates that are inherent to the present generation of forest stand FACE experiments. Physical fractionation by wet sieving revealed an increase in the C and nitrogen (N) content of macro-aggregates due to FACE. Further fractionation by density showed that FACE increased C and N contents of the light iPOM and mineral associated intra-macro-aggregate fractions. Isolation of micro-aggregates from macro-aggregates and subsequent fractionation by density revealed that FACE increased C and N contents of the light iPOM, C content of the fine iPOM and C and N contents of the mineral associated intra-micro-aggregate fractions. From this we infer that the amount of stabilized C and N increased under FACE treatment. We compared our data with published results of other forest FACE experiments and infer that the type of vegetation and soil base saturation, as a proxy for bioturbation, are important factors related to the size of the additional C sinks of the forest floor¿soil system under FACE.
Numerical model to estimate the radiometric performance of net covered structures (AGRONETS) (published on the Conference Proceedings CD)
Hemming, S. ; Swinkels, G.L.A.M. ; Castellano, S. ; Russo, G. ; Scarascia-Mugnozza, G. - \ 2008
Free atmospheric CO2 enrichment (FACE) increased respiration and humification in the mineral soil of a poplar plantation
Hoosbeek, M.R. ; Vos, J.M. ; Meinders, M.B.J. ; Velthorst, E.J. ; Scarascia-Mugnozza, G. - \ 2007
Geoderma 138 (2007)3-4. - ISSN 0016-7061 - p. 204 - 212.
carbon-dioxide enrichment - elevated co2 - biomass production - forest - rotation - popface - turnover - storage - system
Free atmospheric CO2 enrichment (FACE) studies conducted at the whole-tree and ecosystem scale indicate that there is a marked increase in primary production, mainly allocated into below-ground biomass. The enhanced carbon transfer to the root system may result in enhanced rhizodeposition and subsequent transfer to soil C pools. However, the impact of elevated CO2 on soil C contents has yielded variable results. The fate and function of this extra C into the soil in response to elevated CO2 are not clear. The POPFACE experiment was initiated early 1999 with the objective to determine the functional responses of a short-rotation poplar plantation to actual and future atmospheric CO2 concentrations. During the first 2 years of the second rotation (2002¿2003), the increase of total soil C% was larger under FACE than under ambient CO2. Chemical fractionation revealed the presence of more labile soil C under FACE, which is in agreement with the larger input of plant litter and root exudates under FACE. In order to gain insight into the fate and function of this extra C into the soil and the dynamics of soil C, we incubated soil samples, measured respiration rates and used a simple soil C model to interpret the results. FACE increased the accumulated 28-day CO2 production and the initial Cslow pool content (metabolizable plant remains and partly decomposed SOM). FACE also increased the decomposition rates of the metabolizable C pools (Cfast + Cslow) in the top soil, while for the subsoil the opposite effect was observed. The modeled formation of humified SOM was also enhanced by FACE. Our results support the terrestrial feedback hypothesis, i.e. an increase of the long-term terrestrial C sink in response to increasing atmospheric CO2 concentrations
Effects of free atmospheric CO2 enrichment (FACE), N fertilization and poplar genotype on the physical protection of carbon in the mineral soil of a poplar plantation after five years
Hoosbeek, M.R. ; Vos, J.M. ; Bakker, E.J. ; Scarascia-Mugnozza, G. - \ 2006
Biogeosciences 3 (2006)4. - ISSN 1726-4170 - p. 479 - 487.
organic-matter dynamics - elevated co2 - biomass production - cultivated soils - c sequestration - forest - turnover - aggregate - storage - rotation
Free air CO2 enrichment (FACE) experiments in aggrading forests and plantations have demonstrated significant increases in net primary production (NPP) and C storage in forest vegetation. The extra C uptake may also be stored in forest floor litter and in forest soil. After five years of FACE treatment at the EuroFACE short rotation poplar plantation, the increase of total soil C% was larger under elevated than under ambient CO2. However, the fate of this additional C allocated belowground remains unclear. The stability of soil organic matter is controlled by the chemical structure of the organic matter and the formation of micro-aggregates (within macro-aggregates) in which organic matter is stabilized and protected. FACE and N-fertilization treatment did not affect the micro- and macro-aggregate weight, C or N fractions obtained by wet sieving. However, Populus euramericana increased the small macro-aggregate and free micro-aggregate weight and C fractions. The obtained macro-aggregates were broken up in order to isolate recently formed micro-aggregates within macro-aggregates (iM-micro-aggregates). FACE increased the iM-micro-aggregate weight and C fractions, although not significantly. This study reveals that FACE did not affect the formation of aggregates. We did, however, observe a trend of increased stabilization and protection of soil C in micro-aggregates formed within macro-aggregates under FACE. Moreover, the largest effect on aggregate formation was due to differences in species, i.e. poplar genotype. P. euramericana increased the formation of free micro-aggregates which means that more newly incorporated soil C was stabilized and protected. The choice of species in a plantation, or the effect of global change on species diversity, may therefore affect the stabilization and protection of C in soils.
Mycorrhizal hyphal turnover as a dominant process for carbon input into soil organic matter
Godbold, D. ; Hoosbeek, M.R. ; Lukac, M. ; Francesca Cotrufo, M. ; Janssens, I.A. ; Ceulemans, R. ; Polle, A. ; Velthorst, E.J. ; Scarascia-Mugnozza, G. ; Angelis, P. de; Miglietta, F. ; Peressotti, A. - \ 2006
Plant and Soil 281 (2006)1-2. - ISSN 0032-079X - p. 15 - 24.
elevated atmospheric co2 - douglas-fir ecosystem - 1st growing-season - ectomycorrhizal fungi - forest ecosystems - external mycelium - root turnover - enrichment - nitrogen - patterns
The atmospheric concentration of CO2 is predicted to reach double current levels by 2075. Detritus from aboveground and belowground plant parts constitutes the primary source of C for soil organic matter (SOM), and accumulation of SOM in forests may provide a significant mechanism to mitigate increasing atmospheric CO2 concentrations. In a poplar (three species) plantation exposed to ambient (380 ppm) and elevated (580 ppm) atmospheric CO2 concentrations using a Free Air Carbon Dioxide Enrichment (FACE) system, the relative importance of leaf litter decomposition, fine root and fungal turnover for C incorporation into SOM was investigated. A technique using cores of soil in which a C-4 crop has been grown (delta C-13 -18.1 parts per thousand) inserted into the plantation and detritus from C-3 trees (delta C-13 -27 to -30 parts per thousand) was used to distinguish between old (native soil) and new (tree derived) soil C. In-growth cores using a fine mesh (39 mu m) to prevent in-growth of roots, but allow in-growth of fungal hyphae were used to assess contribution of fine roots and the mycorrhizal external mycelium to soil C during a period of three growing seasons (1999-2001). Across all species and treatments, the mycorrhizal external mycelium was the dominant pathway (62%) through which carbon entered the SOM pool, exceeding the input via leaf litter and fine root turnover. The input via the mycorrhizal external mycelium was not influenced by elevated CO2, but elevated atmospheric CO2 enhanced soil C inputs via fine root turnover. The turnover of the mycorrhizal external mycelium may be a fundamental mechanism for the transfer of root-derived C to SOM.
|Responses to elevated [CO2] of a short rotation multispecies poplar plantation: the POPFACE/EUROFACE experiment
Scarascia-Mugnozza, G. ; Calfapietra, C. ; Ceulemans, R. ; Gielen, B. ; Cotrufo, M.F. ; DeAngelis, P. ; Godbold, D. ; Hoosbeek, M.R. ; Kull, O. ; Lukac, M. ; Marek, M. ; Miglietta, F. ; Polle, A. ; Raines, C. ; Sabatti, M. ; Anselmi, N. ; Taylor, G. - \ 2006
In: Managed Ecosystems and CO2 / Nösberger, J., Long, S.P., Norby, R.J., Stitt, M., Hendrey, G.R., Blum, H., Heidelberg : Springer-Verlag (Ecological Studies 187) - ISBN 9783540312369 - p. 173 - 185.
Woody biomass production during the second rotation of a bio-energy Populus plantation increases in a future high CO2 world
Liberloo, M. ; Calfapietra, C. ; Lukac, M. ; Godbold, D. ; Luos, Z.B. ; Polles, A. ; Hoosbeek, M.R. ; Kull, O. ; Marek, M. ; Rianes, Chr. ; Rubino, M. ; Taylors, G. ; Scarascia-Mugnozza, G. ; Ceulemans, R. - \ 2006
Global Change Biology 12 (2006)6. - ISSN 1354-1013 - p. 1094 - 1106.
elevated co2 - atmospheric co2 - poplar plantation - enrichment face - no3 availability - n-fertilization - hybrid poplar - water-stress - pinus-taeda - growth
The quickly rising atmospheric carbon dioxide (CO2)-levels, justify the need to explore all carbon (C) sequestration possibilities that might mitigate the current CO2 increase. Here, we report the likely impact of future increases in atmospheric CO2 on woody biomass production of three poplar species (Populus alba L. clone 2AS-11, Populus nigra L. clone Jean Pourtet and Populus×euramericana clone I-214). Trees were growing in a high-density coppice plantation during the second rotation (i.e., regrowth after coppice; 2002¿2004; POPFACE/EUROFACE). Six plots were studied, half of which were continuously fumigated with CO2 (FACE; free air carbon dioxide enrichment of 550 ppm). Half of each plot was fertilized to study the interaction between CO2 and nutrient fertilization. At the end of the second rotation, selective above- and belowground harvests were performed to estimate the productivity of this bio-energy plantation. Fertilization did not affect growth of the poplar trees, which was likely because of the high rates of fertilization during the previous agricultural land use. In contrast, elevated CO2 enhanced biomass production by up to 29%, and this stimulation did not differ between above- and belowground parts. The increased initial stump size resulting from elevated CO2 during the first rotation (1999¿2001) could not solely explain the observed final biomass increase. The larger leaf area index after canopy closure and the absence of any major photosynthetic acclimation after 6 years of fumigation caused the sustained CO2-induced biomass increase after coppice. These results suggest that, under future CO2 concentrations, managed poplar coppice systems may exhibit higher potential for C sequestration and, thus, help mitigate climate change when used as a source of C-neutral energy.
Free air CO2 enrichment (FACE) increased litter build up and soil C sequestration in a short-rotation Poplar plantation in central Italy
Hoosbeek, M.R. ; Vos, J.M. ; Scarascia-Mugnozza, G. - \ 2006
Geophysical Research Abstracts 8 (2006)07122. - ISSN 1029-7006
Global change and agro-forest ecosystems: Adaptation and mitigation in a FACE experiment on a poplar plantation
Scarascia-Mugnozza, G. ; Angelis, P. de; Sabatti, M. ; Calfapietra, C. ; Miglietta, F. ; Raines, C. ; Godbold, D. ; Hoosbeek, M.R. ; Taylor, G. ; Polle, A. ; Ceulemans, R. - \ 2005
Plant Biosystems 139 (2005)3. - ISSN 1126-3504 - p. 255 - 264.
elevated atmospheric co2 - carbon-dioxide - enrichment popface - short-rotation - mycorrhizal colonization - betula-papyrifera - field - responses - growth - soil
The objective of this research was to determine the functional responses of a cultivated, agro-forestry system, namely a poplar plantation, to actual and future atmospheric CO2 concentrations. Hence, this research has combined a fast growing, agro-forestry ecosystem, capable of elevated biomass production, with a large-scale Free Air Carbon Enrichment (FACE) system, one of the few available in the European Union on a forest tree stand. The FACE facility is located close to a natural CO2 source and is drawing scientists from several European countries, and from other continents, to closely cooperate and combine their scientific efforts on the same experimental system. Furthermore, this FACE apparatus utilizes a novel technology, originally developed by Italian institutions, based on the release into the atmosphere, at sonic velocity, of pure CO2 instead of an air-CO2 Mixture. The research activities conducted at the POPFACE site, on the responses of the tree plantation to future atmospheric conditions, have integrated observations at the leaf level, such as photosynthesis, respiration and transpiration, with measures carried out at the whole-tree and stand scale, such as canopy architecture, light interception and biomass production. Finally, the ecosystem dimension has also been analysed by studying root productivity and soil processes, host-parasite interactions, and carbon sequestration throughout a rotation. cycle of the stand.
Net carbon storage in a popular plantation (POPFACE) after three years of free-air CO2 enrichment
Gielen, B. ; Calfapietra, C. ; Lukac, M. ; Wittig, V.E. ; Angelis, P. de; Janssens, I.A. ; Moscatelli, M.C. ; Grego, S. ; Cotrufo, M.F. ; Godbold, D. ; Hoosbeek, M.R. ; Long, S. ; Miglietta, F. ; Polle, A. ; Bernacchi, C. ; Davey, P.A. ; Ceulemans, R. ; Scarascia-Mugnozza, G. - \ 2005
Tree Physiology 25 (2005)11. - ISSN 0829-318X - p. 1399 - 1408.
temperature response functions - elevated atmospheric co2 - soil organic-matter - limited photosynthesis - dioxide enrichment - microbial biomass - turnover - forest - populus - dynamics
A high-density plantation of three genotypes of Populus was exposed to an elevated concentration of carbon dioxide ([CO2]; 550 µmol mol¿1) from planting through canopy closure using a free-air CO2 enrichment (FACE) technique. The FACE treatment stimulated gross primary productivity by 22 and 11% in the second and third years, respectively. Partitioning of extra carbon (C) among C pools of different turnover rates is of critical interest; thus, we calculated net ecosystem productivity (NEP) to determine whether elevated atmospheric [CO2] will enhance net plantation C storage capacity. Free-air CO2 enrichment increased net primary productivity (NPP) of all genotypes by 21% in the second year and by 26% in the third year, mainly because of an increase in the size of C pools with relatively slow turnover rates (i.e., wood). In all genotypes in the FACE treatment, more new soil C was added to the total soil C pool compared with the control treatment. However, more old soil C loss was observed in the FACE treatment compared with the control treatment, possibly due to a priming effect from newly incorporated root litter. FACE did not significantly increase NEP, probably as a result of this priming effect.
More new carbon in the mineral soil of a poplar plantation under Free Air Carbon Erichment (POPFACE): Cause of increased priming effect?
Hoosbeek, M.R. ; Lukac, M. ; Dam, D. ; Godbold, D. ; Velthorst, E.J. ; Bondi, F.A. ; Peressotti, A. ; Cotrufo, M.F. ; Angelis, P. de; Scarascia-Mugnozza, G. - \ 2004
Global Biogeochemical Cycles 18 (2004)1. - ISSN 0886-6236 - 7 p.
elevated atmospheric co2 - organic-matter - terrestrial ecosystems - turnover - forest - storage - system - decomposition - mechanisms - feedbacks
 In order to establish suitability of forest ecosystems for long-term storage of C, it is necessary to characterize the effects of predicted increased atmospheric CO2 levels on the pools and fluxes of C within these systems. Since most C held in terrestrial ecosystems is in the soil, we assessed the influence of Free Air Carbon Enrichment (FACE) treatment on the total soil C content (C-total) and incorporation of litter derived C (C-new) into soil organic matter (SOM) in a fast growing poplar plantation. C-new was estimated by the C3/C4 stable isotope method. C-total contents increased under control and FACE respectively by 12 and 3%, i.e., 484 and 107 gC/m(2), while 704 and 926 gC/m(2) of new carbon was sequestered under control and FACE during the experiment. We conclude that FACE suppressed the increase of C-total and simultaneously increased C-new. We hypothesize that these opposite effects may be caused by a priming effect of the newly incorporated litter, where priming effect is defined as the stimulation of SOM decomposition caused by the addition of labile substrates.
|More new carbon in the mineral soil if a popular plantation under FACE (POPFACE)
Hoosbeek, M.R. ; Lukac, M. ; Dam, D. ; Godbold, D. ; Velthorst, E.J. ; Biondi, F.A. ; Peressotti, A. ; Gotrufo, M.F. ; Angelis, P. de; Scarascia-Mugnozza, G. - \ 2004
|Long-term responses of a poplar agroforestry system to elevated CO2: tree growth, biomass productivity and carbon pools
Scarascia-Mugnozza, G. ; Calfapietra, C. ; Gielen, B. ; Angelis, P. de; Liberloo, M. ; Lukac, M. ; Godbold, D. ; Cotrufo, M.F. ; Hoosbeek, M.R. ; Taylor, G. ; Raines, C. ; Marek, M. ; Kull, O. ; Miglietta, F. ; Polle, A. ; Ceulemans, R. - \ 2004
Free-air CO2 enrichment (FACE) enhances biomass production in a short-rotation poplar plantation
Calfapietra, C. ; Gielen, B. ; Galema, A.N.J. ; Lukac, M. ; Angelis, P. de; Moscatelli, M.C. ; Ceulemans, R. ; Scarascia-Mugnozza, G. - \ 2003
Tree Physiology 23 (2003). - ISSN 0829-318X - p. 805 - 814.
elevated atmospheric co2 - carbon-dioxide enrichment - net primary production - light-use efficiency - soil n-availability - hybrid poplar - populus-grandidentata - crown architecture - pinus-sylvestris - fine roots
This paper investigates the possible contribution of Short Rotation Cultures (SRC) to carbon sequestration in both current and elevated atmospheric CO2 concentrations ([CO2]). A dense poplar plantation (1 x 1 m) was exposed to a [CO2] of 550 ppm in Central Italy using the free-air CO2 enrichment (FACE) technique. Three species of Populus were examined, namely P. alba L., P. nigra L. and P. x euramericana Dode (Guinier). Aboveground woody biomass of trees exposed to elevated [CO2] for three growing seasons increased by 15 to 27%, depending on species. As a result, light-use efficiency increased. Aboveground biomass allocation was unaffected, and belowground biomass also increased under elevated [CO2] conditions, by 22 to 38%. Populus nigra, with total biomass equal to 62.02 and 72.03 Mg ha(-1) in ambient and elevated [CO2], respectively, was the most productive species, although its productivity was stimulated least by atmospheric CO2 enrichment. There was greater depletion of inorganic nitrogen from the soil after three growing seasons in elevated [CO2], but no effect of [CO2] on stem wood density, which differed significantly only among species.