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Sink or source?

uncertainties in large scale model predictions of forest soil organic carbon dynamics

Ortiz, Carina A. (2012). Sink or source? Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2012:25
ISBN 978-91-576-7661-0
[Doctoral thesis]

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Soil organic carbon (SOC) is the largest terrestrial carbon pool and small changes in this pool may affect the global carbon balance, especially atmospheric concentration of CO2. Within the context of climate policy, the quantification of these changes is important, as pool changes may affect a country's national greenhouse gas budget.

The aim of this thesis was to assess and analyze uncertainty related to the up-scaling of modelled SOC stocks and change estimates to regional or national scale. Two process-based models Q and Yasso07, were used to estimate SOC stocks and changes at different regional scales in Swedish coniferous forests. The parameter uncertainty of the Q model was assessed and established with the Generalized Likelihood Uncertainty Estimation (GLUE) method through the Swedish Forest Soil Inventory (SFSI) data at county scale. The calibration resulted in a set of parameters that were used for further modeling at regional scale. The Q and Yasso07 models were used to assess the impact of different uncertainties in the SOC stocks and changes. The most important uncertainty source in the model estimates was litter production. Increased harvest residue extraction was analyzed with the Q model to study the effects on SOC accumulation. SOC accumulation decreased with increased harvest residue extraction, although there was temporal and geographical variation. However, increased emissions from changes in the SOC pool resulted in a net decrease in CO2 emissions due to the substitution of coal combustion with biofuels.

The coherence of scales between large-scale inventory data and process-based simulation models was explored. Inventory data became more uncertain when going from national to regional scale, due to the smaller sample, whereas, model estimates became more uncertain when applied to larger areas, due to increased uncertainty in parameter determination at larger scales resulting from varying conditions. The magnitudes of the uncertainties for model and inventory estimates of SOC were comparable, but the origins of uncertainties differed and could not be compared. Both models and inventories can be used to estimate the carbon sink of Swedish forest soils at national level, but if the changes are small, a few ‰ yr-1 in the SOC pool, the uncertainty may prevent a definite answer, if there is a change in the SOC pool.

Authors/Creators:Ortiz, Carina A.
Title:Sink or source?
Subtitle:uncertainties in large scale model predictions of forest soil organic carbon dynamics
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :April 2012
Number of Pages:70
I.Ortiz, C.A., Karltun, E., Stendahl, J., Gärdenäs, A.I., Ågren, G.I. (2011). Modelling soil carbon development in Swedish coniferous forest soils –An uncertainty analysis of parameters and model estimates using the GLUE method. Ecological Modelling 222 (2011), 3020-3032.
II.Ortiz, C.A., Liski, J., Gärdenäs, A.I., Lehtonen, A., Lundblad, M., Stendahl, J., Karltun, E. Soil organic carbon stock changes in Swedish forest soils – a comparison of uncertainties and their sources through a national inventory and two simulation models. (manuscript).
III.Ortiz, C-.A., Gärdenäs, A.I., Karltun, E., Ågren, G.I. Model predictions of soil carbon development over a stand age: What is most important sensitivity to climate or model parameter uncertainty? (manuscript).
IV.Ortiz, C.A., Lundblad, M., Lundström, A., Stendahl, J. The effect on soil organic carbon accumulation of increased extraction of forest harvest residuals for bioenergy use in Sweden. (manuscript).
Place of Publication:Uppsala
Publisher:Dept. of Soil and Environment, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7661-0
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K01 Forestry - General aspects
P Natural resources > P06 Renewable energy resources
P Natural resources > P31 Soil surveys and mapping
P Natural resources > P33 Soil chemistry and physics
U Auxiliary disciplines > U10 Mathematical and statistical methods
U Auxiliary disciplines > U40 Surveying methods
Subjects:Obsolete subject words > FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING > Soil science > Soil physics
Obsolete subject words > FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING > Soil science > Soil chemistry
Obsolete subject words > FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING > Soil science > Soil biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Climate Research
Agrovoc terms:coniferous forests, forest soils, carbon, soil organic matter, forest litter, carbon dioxide, climatic change, simulation models, statistical uncertainty, forest inventories, sweden
Keywords:SOC, GLUE, Swedish Forest Soil Inventory, models, uncertainty, GHG reporting, sensitivity analysis, coniferous forests
Permanent URL:
ID Code:8695
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: Carina A. Ortiz
Deposited On:12 Apr 2012 09:18
Metadata Last Modified:02 Dec 2014 10:49

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