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Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites.

De Kauwe MG, Medlyn BE, Zaehle S, Walker AP, Dietze MC, Wang YP, Luo Y, Jain AK, El-Masri B, Hickler T, Wårlind D, Weng E, Parton WJ, Thornton PE, Wang S, Prentice IC, Asao S, Smith B, McCarthy HR, Iversen CM, Hanson PJ, Warren JM, Oren R, Norby RJ - New Phytol. (2014)

Bottom Line: Observed eCO2 effects on allocation were dynamic.Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes.Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.

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Related in: MedlinePlus

Fractions of Net Primary Productivity (NPP) allocated at ambient CO2 to the foliage,wood, fine roots and reproduction at (a) Duke and (b) Oak Ridge. The values shown are means of theannual values and the error bars show the interannual variability in allocation fractions (±1SD) calculated over the number of years (n) of the experiment(n = 10 at Duke andn = 11 at Oak Ridge). Models are grouped by allocation modeltype. Observations are shown by the abbreviation ‘OBS’. Further discussion ofdifferences among model predictions of allocation patterns at ambient CO2 concentrationis provided in Table 1 and in Supporting Information NotesS2.
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fig01: Fractions of Net Primary Productivity (NPP) allocated at ambient CO2 to the foliage,wood, fine roots and reproduction at (a) Duke and (b) Oak Ridge. The values shown are means of theannual values and the error bars show the interannual variability in allocation fractions (±1SD) calculated over the number of years (n) of the experiment(n = 10 at Duke andn = 11 at Oak Ridge). Models are grouped by allocation modeltype. Observations are shown by the abbreviation ‘OBS’. Further discussion ofdifferences among model predictions of allocation patterns at ambient CO2 concentrationis provided in Table 1 and in Supporting Information NotesS2.

Mentions: Figure 1 shows the average measured and modelled Callocation coefficients in the ambient treatments over the experimental period at both sites. Atboth sites, the observations indicate that the largest fraction of NPP goes to wood, but at Duke thewood allocation fraction is greater, and the root allocation fraction lower, than at ORNL. Overall,the models agree with the observations that the greatest fraction of NPP was allocated to woodytissue at both sites, with notable exceptions being LPJ-GUESS and O-CN at Duke, and O-CN and TECO atORNL. Most differences among models in their prediction of allocation fractions at ambientCO2 arise from parameterisation; these differences are discussed in the Notes S2.


Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites.

De Kauwe MG, Medlyn BE, Zaehle S, Walker AP, Dietze MC, Wang YP, Luo Y, Jain AK, El-Masri B, Hickler T, Wårlind D, Weng E, Parton WJ, Thornton PE, Wang S, Prentice IC, Asao S, Smith B, McCarthy HR, Iversen CM, Hanson PJ, Warren JM, Oren R, Norby RJ - New Phytol. (2014)

Fractions of Net Primary Productivity (NPP) allocated at ambient CO2 to the foliage,wood, fine roots and reproduction at (a) Duke and (b) Oak Ridge. The values shown are means of theannual values and the error bars show the interannual variability in allocation fractions (±1SD) calculated over the number of years (n) of the experiment(n = 10 at Duke andn = 11 at Oak Ridge). Models are grouped by allocation modeltype. Observations are shown by the abbreviation ‘OBS’. Further discussion ofdifferences among model predictions of allocation patterns at ambient CO2 concentrationis provided in Table 1 and in Supporting Information NotesS2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260117&req=5

fig01: Fractions of Net Primary Productivity (NPP) allocated at ambient CO2 to the foliage,wood, fine roots and reproduction at (a) Duke and (b) Oak Ridge. The values shown are means of theannual values and the error bars show the interannual variability in allocation fractions (±1SD) calculated over the number of years (n) of the experiment(n = 10 at Duke andn = 11 at Oak Ridge). Models are grouped by allocation modeltype. Observations are shown by the abbreviation ‘OBS’. Further discussion ofdifferences among model predictions of allocation patterns at ambient CO2 concentrationis provided in Table 1 and in Supporting Information NotesS2.
Mentions: Figure 1 shows the average measured and modelled Callocation coefficients in the ambient treatments over the experimental period at both sites. Atboth sites, the observations indicate that the largest fraction of NPP goes to wood, but at Duke thewood allocation fraction is greater, and the root allocation fraction lower, than at ORNL. Overall,the models agree with the observations that the greatest fraction of NPP was allocated to woodytissue at both sites, with notable exceptions being LPJ-GUESS and O-CN at Duke, and O-CN and TECO atORNL. Most differences among models in their prediction of allocation fractions at ambientCO2 arise from parameterisation; these differences are discussed in the Notes S2.

Bottom Line: Observed eCO2 effects on allocation were dynamic.Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes.Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.

Show MeSH
Related in: MedlinePlus