Calibration and validation of a simplified process-based model for the prediction of the carbon balance of Scottish Sitka spruce (Picea sitchensis) plantations

2010 ◽  
Vol 40 (12) ◽  
pp. 2411-2426 ◽  
Author(s):  
Francesco Minunno ◽  
Georgios Xenakis ◽  
Michael P. Perks ◽  
Maurizio Mencuccini

There is increasing recognition that forestry provides a low cost and robust means of climate change abatement through carbon sequestration and substitution. However, current understanding of forest ecosystem carbon exchange and forest–atmosphere interactions are often inadequately characterized by existing empirical growth models with resulting poor representation for regional extrapolations. In this paper, we describe the parameterisation and independent validation, against both eddy covariance and forest growth experimental data, of a process-oriented model 3PGN to provide assessments of carbon sequestration of Sitka spruce (Picea sitchensis (Bong.) Carrière) plantations across Scotland. In comparison with eddy covariance measurements, the model predicted all of the major annual carbon fluxes, i.e., gross primary production (PG), net ecosystem production (PE), and ecosystem respiration (RE), with biases lower than 10%. At a monthly time step, only PG and PE were accurately estimated, whereas RE was not. At longer time scales (i.e., several decades), the model reliably represented the major patterns of the carbon balance. Soil type was identified as the important factor influencing site productivity; fertilization practices did not alter long-term site nutritional status. The analyses also highlighted the potential impact of carbon loss from carbon-rich soils, which can result in differences between optimal rotation length for carbon sequestration and for timber production.

Author(s):  
Robert Hall ◽  
Jennifer Tank ◽  
Michelle Baker ◽  
Emma Rosi-Marshall ◽  
Michael Grace ◽  
...  

Primary production and respiration are core functions of river ecosystems that in part determine the carbon balance. Gross primary production (GPP) is the total rate of carbon fixation by autotrophs such as algae and higher plants and is equivalent to photosynthesis. Ecosystem respiration (ER) measures rate at which organic carbon is mineralized to CO2 by all organisms in an ecosystem. Together these fluxes can indicate the base of the food web to support animal production (Marcarelli et al. 2011), can predict the cycling of other elements (Hall and Tank 2003), and can link ecosystems to global carbon cycling (Cole et al. 2007).


2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Víctor Cicuéndez ◽  
Javier Litago ◽  
Víctor Sánchez-Girón ◽  
Laura Recuero ◽  
César Sáenz ◽  
...  

Gross primary production (GPP) represents the carbon (C) uptake of ecosystems through photosynthesis and it is the largest flux of the global carbon balance. Our overall objective in this research is to identify and model GPP dynamics and its relationship with meteorological variables and energy fluxes based on time series analysis of eddy covariance (EC) data in two different agroecosystems, a Mediterranean rice crop in Spain and a rainfed cropland in Germany. Crops exerted an important influence on the energy and water fluxes dynamics existing a clear feedback between GPP, meteorological variables and energy fluxes in both type of crops.


2009 ◽  
Vol 6 (4) ◽  
pp. 6601-6634 ◽  
Author(s):  
B. Bjarnadottir ◽  
B. D. Sigurdsson ◽  
A. Lindroth

Abstract. This study reports 3-year measurements (2004–2006) of net ecosystem exchange (NEE) over a 12–14 year old Siberian larch forest in Iceland established on previously grazed heath land pasture that had been site-prepared prior to planting. The study evaluated interannual and seasonal variation of NEE and its component fluxes, gross primary production (GPP) and ecosystem respiration (Re), with the aim to clarify how climatic factors controlled the site's carbon balance. The young plantation acted as a relatively strong sink for CO2 during all of the three years, with a net sequestration of −375, −566 and −245 g CO2 m−2 for years 2004, 2005 and 2006, respectively. The annual carbon balance was strongly influenced by climatic factors leading to a high inter-annual variability in NEE. This variation was more related to variation in carbon efflux (Re) than carbon uptake (GPP). The abiotic factors that showed the strongest correlation to Re were air temperature during the growing season and soil water potential. The GPP mostly followed the seasonal pattern in irradiance, except in 2005, when the plantation experienced severe spring frost damage that set the GPP back to zero. It was not expected that the rather slow-growing Siberian larch plantation would be such a strong sink for atmospheric CO2 only twelve years after site preparation and afforestation.


2006 ◽  
Vol 3 (4) ◽  
pp. 571-583 ◽  
Author(s):  
D. Papale ◽  
M. Reichstein ◽  
M. Aubinet ◽  
E. Canfora ◽  
C. Bernhofer ◽  
...  

Abstract. Eddy covariance technique to measure CO2, water and energy fluxes between biosphere and atmosphere is widely spread and used in various regional networks. Currently more than 250 eddy covariance sites are active around the world measuring carbon exchange at high temporal resolution for different biomes and climatic conditions. In this paper a new standardized set of corrections is introduced and the uncertainties associated with these corrections are assessed for eight different forest sites in Europe with a total of 12 yearly datasets. The uncertainties introduced on the two components GPP (Gross Primary Production) and TER (Terrestrial Ecosystem Respiration) are also discussed and a quantitative analysis presented. Through a factorial analysis we find that generally, uncertainties by different corrections are additive without interactions and that the heuristic u*-correction introduces the largest uncertainty. The results show that a standardized data processing is needed for an effective comparison across biomes and for underpinning inter-annual variability. The methodology presented in this paper has also been integrated in the European database of the eddy covariance measurements.


2015 ◽  
Vol 12 (23) ◽  
pp. 6837-6851 ◽  
Author(s):  
K. Yamanoi ◽  
Y. Mizoguchi ◽  
H. Utsugi

Abstract. Forests play an important role in the terrestrial carbon balance, with most being in a carbon sequestration stage. The net carbon releases that occur result from forest disturbance, and windthrow is a typical disturbance event affecting the forest carbon balance in eastern Asia. The CO2 flux has been measured using the eddy covariance method in a deciduous broadleaf forest (Japanese white birch, Japanese oak, and castor aralia) in Hokkaido, where incidental damage by the strong Typhoon Songda in 2004 occurred. We also used the biometrical method to demonstrate the CO2 flux within the forest in detail. Damaged trees amounted to 40 % of all trees, and they remained on site where they were not extracted by forest management. Gross primary production (GPP), ecosystem respiration (Re), and net ecosystem production were 1350, 975, and 375 g C m−2 yr−1 before the disturbance and 1262, 1359, and −97 g C m−2 yr−1 2 years after the disturbance, respectively. Before the disturbance, the forest was an evident carbon sink, and it subsequently transformed into a net carbon source. Because of increased light intensity at the forest floor, the leaf area index and biomass of the undergrowth (Sasa kurilensis and S. senanensis) increased by factors of 2.4 and 1.7, respectively, in 3 years subsequent to the disturbance. The photosynthesis of Sasa increased rapidly and contributed to the total GPP after the disturbance. The annual GPP only decreased by 6 % just after the disturbance. On the other hand, the annual Re increased by 39 % mainly because of the decomposition of residual coarse-wood debris. The carbon balance after the disturbance was controlled by the new growth and the decomposition of residues. The forest management, which resulted in the dead trees remaining at the study site, strongly affected the carbon balance over the years. When comparing the carbon uptake efficiency at the study site with that at others, including those with various kinds of disturbances, we emphasized the importance of forest management as well as disturbance type in the carbon balance.


2017 ◽  
Vol 42 (2) ◽  
pp. 162-184 ◽  
Author(s):  
Anna-Maria Virkkala ◽  
Tarmo Virtanen ◽  
Aleksi Lehtonen ◽  
Janne Rinne ◽  
Miska Luoto

The Arctic tundra plays an important role in the carbon cycle as it stores 50% of global soil organic carbon reservoirs. The processes (fluxes) regulating these stocks are predicted to change due to direct and indirect effects of climate change. Understanding the current and future carbon balance calls for a summary of the level of knowledge regarding chamber-derived carbon dioxide (CO2) flux studies. Here, we describe progress from recently (2000–2016) published studies of growing-season CO2 flux chamber measurements, namely GPP (gross primary production), ER (ecosystem respiration), and NEE (net ecosystem exchange), in the tundra region. We review the study areas and designs along with the explanatory environmental drivers used. Most of the studies were conducted in Alaska and Fennoscandia, and we stress the need for measuring fluxes in other tundra regions, particularly in more extreme climatic, productivity, and soil conditions. Soil respiration and other greenhouse gas measurements were seldom included in the studies. Although most of the environmental drivers of CO2 fluxes have been relatively well investigated (such as the effect of vegetation type and soil microclimate on fluxes), soil nutrients, other greenhouse gases and disturbance regimes require more research as they might define the future carbon balance. Particular attention should be paid to the effects of shrubification, geomorphology, and other disturbance effects such as fire events, and disease and herbivore outbreaks. An improved conceptual framework and understanding of underlying processes of biosphere–atmosphere CO2 exchange will provide more information on carbon cycling in the tundra.


2016 ◽  
Author(s):  
John E. Hunt ◽  
Johannes Laubach ◽  
Matti Barthel ◽  
Anitra Fraser ◽  
Rebecca L. Phillips

Abstract. Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock grazing intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised, and rotationally-grazed dairy pasture and a neighbouring unirrigated, unfertilised, winter-grazed pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass-carbon removed by grazing cows, and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-grazing. Excreta deposition was calculated from animal feed intake. The intensively-managed pasture gained C (NECB = 103 ±42 g C m−2 yr−1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = −13 ±23 g C m−2 yr−1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m−2 yr−1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m−2 yr−1). The irrigated pasture used the total annual water input 37 % more efficiently than the unirrigated pasture to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of grazed grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.


2020 ◽  
Author(s):  
Aurelio Guevara-Escobar ◽  
Enrique González-Sosa ◽  
Mónica Cervantes-Jiménez ◽  
Humberto Suzán-Azpiri ◽  
Mónica Elisa Queijeiro-Bolaños ◽  
...  

Abstract. Vegetation fixes C in its biomass through photosynthesis or might release it into the atmosphere through respiration. Measurements of these fluxes would help us understand ecosystem functioning. The eddy covariance technique (EC) is widely used to measure the net ecosystem exchange of C (NEE) which is the balance between gross primary production (GPP) and ecosystem respiration (Reco). Orbital satellites such as MODIS can also provide estimates of GPP. In this study, we measured NEE with the EC in a scrub at Bernal in Mexico, and then partitioned into gross primary production (GPP-EC) and Reco using the recent R package Reddyproc. Measurements of GPP-EC were related to the estimates from the MODIS satellite provided in product MOD17A2H, which contains data of the gross primary productivity (GPP-MODIS). The Bernal site was a carbon sink despite it was an overgrazed site, the average NEE during fifteen months of 2017 and 2018 was −0.78 g C m−2 d−1 and the flux was negative in all measured months. The GPP-MODIS underestimated the ground data when representing the relation with a Theil-Sen regression: GPP-EC = 1.866 + 1.861 GPP-MODIS; an ordinary less squares regression had similar coefficients and the R2 was 0.6. Although cacti (CAM), legume shrubs (C3) and herbs (C3) had a similar vegetation index, the nighttime flux was characterized by positive NEE suggesting that the photosynthetic dark-cycle flux of cacti was lower than Reco. The discrepancy among the GPP flux estimates stresses the need to understand the limitations of EC and remote sensors, while incorporating complementary monitoring and modelling schemes of nighttime Reco, particularly in the presence of species with different photosynthetic cycles.


2008 ◽  
Vol 5 (5) ◽  
pp. 4035-4069 ◽  
Author(s):  
U. Weber ◽  
M. Jung ◽  
M. Reichstein ◽  
C. Beer ◽  
M. Braakhekke ◽  
...  

Abstract. We are comparing spatially explicit process-model based estimates of the terrestrial carbon balance and its components over Africa and confront them with remote sensing based proxies of vegetation productivity and atmospheric inversions of land-atmosphere net carbon exchange. Particular emphasis is on characterizing the patterns of interannual variability of carbon fluxes and analyzing the factors and processes responsible for it. For this purpose simulations with the terrestrial biosphere models ORCHIDEE, LPJ-DGVM, LPJ-Guess and JULES have been performed using a standardized modeling protocol and a uniform set of corrected climate forcing data. While the models differ concerning the absolute magnitude of carbon fluxes, we find several robust patterns of interannual variability among the models. Models exhibit largest interannual variability in southern and eastern Africa, regions which are primarily covered by herbaceous vegetation. Interannual variability of the net carbon balance appears to be more strongly influenced by gross primary production than by ecosystem respiration. A principal component analysis indicates that moisture is the main driving factor of interannual gross primary production variability for those regions. On the contrary in a large part of the inner tropics radiation appears to be limiting in two models. These patterns are corroborated by remotely sensed vegetation properties from the SeaWiFS satellite sensor. Inverse atmospheric modeling estimates of surface carbon fluxes are less conclusive at this point, implying the need for a denser network of observation stations over Africa.


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