Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

Abstract. This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-Alpine region of southern Germany. The sites are separated by only 10 km, they share the same soil formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo ssp. rotundata) grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies) grows on drained and degraded peat (3.4 m). The net ecosystem exchange of CO2 (NEE) at both sites has been investigated for 2 years (July 2010–June 2012), using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (−130 ± 31 and −300 ± 66 g C m−2 a−1 in the first and second year, respectively) than the natural bog forest at Schechenfilz (−53 ± 28 and −73 ± 38 g C m−2 a−1). The strong net CO2 uptake can be explained by the high gross primary productivity of the 44-year old spruces that over-compensates the two-times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger plant area index (PAI) of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source when the whole life-cycle since forest planting is considered. It is important to access this result in terms of the long-term biome balance. To do so, we used historical data to estimate the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. This rough estimate indicates a strong carbon release of +134 t C ha−1 within the last 44 years. Thus, the spruces would need to grow for another 100 years at about the current rate, to compensate the potential peat loss of the former years. In contrast, the natural bog-pine ecosystem has likely been a small but stable carbon sink for decades, which our results suggest is very robust regarding short-term changes of environmental factors.

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Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

Biogeosciences Discussions ◽

10.5194/bgd-11-2189-2014 ◽

2014 ◽

Vol 11 (2) ◽

pp. 2189-2226 ◽

Cited By ~ 2

Author(s):

J. Hommeltenberg ◽

H. P. Schmid ◽

M. Droesler ◽

P. Werle

Keyword(s):

Carbon Fixation ◽

Carbon Sink ◽

Ecosystem Respiration ◽

Net Ecosystem Exchange ◽

Weather Conditions ◽

Co2 Exchange ◽

Co2 Uptake ◽

Spruce Forest ◽

The Difference ◽

Whole Life Cycle

Abstract. This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-alpine region of southern Germany. The sites are separated by only ten kilometers, they share the same formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo rotundata) grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies) grows on drained and degraded peat (3.4 m). The net ecosystem exchange of CO2 (NEE) at both sites has been investigated for two years (July 2010 to June 2012), using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (−130 ± 31 and −300 ± 66 g C m−2 a−1 in the first and second year respectively) than the natural bog forest at Schechenfilz (−53 ± 28 and −73±38 g C m−2 a−1). The strong net CO2 uptake can be explained by the high gross primary productivity of the spruces that over-compensates the two times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger LAI of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source, if the whole life-cycle, since forest planting is considered. We determined the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. The estimate resulted in a strong carbon release of +156 t C ha−1 within the last 44 yr, means the spruces would need to grow for another 100 yr, at the current rate, to compensate the peat loss of the former years. In contrast, the natural bog-pine ecosystem has likely been a small but consistent carbon sink for decades, which our results suggest is very robust regarding short-term changes of environmental factors.

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Daily and seasonal patterns of CO2 fluxes and evapotranspiration in maize-grass intercropping

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v20n9p777-782 ◽

2016 ◽

Vol 20 (9) ◽

pp. 777-782 ◽

Cited By ~ 3

Author(s):

Cássia B. Machado ◽

José R. de S. Lima ◽

Antonio C. D. Antonino ◽

Eduardo S. de Souza ◽

Rodolfo M. S. Souza ◽

...

Keyword(s):

Soil Water ◽

Climate Changes ◽

Carbon Sink ◽

Soil Water Storage ◽

Co2 Uptake ◽

Co2 Fluxes ◽

Area Index ◽

Available Energy ◽

Atmospheric Carbon ◽

Main Consumer

ABSTRACT Studies that investigate the relationships between CO2 fluxes and evapotranspiration (ET) are important for predicting how agricultural ecosystems will respond to climate changes. However, none was made on the maize-grass intercropping system in Brazil. The aim of this study was to determine the ET and CO2 fluxes in a signal grass pasture intercropped with maize, in São João, Pernambuco, Brazil, in a drought year. Furthermore, the soil water storage (SWS) and leaf area index (LAI) were determined. The latent heat flux was the main consumer of the available energy and the daily and seasonal ET and CO2 variations were mainly controlled by rainfall, through the changes in soil water content and consequently in SWS. The agroecosystem acted as an atmospheric carbon source, during drier periods and lower LAI, and as an atmospheric carbon sink, during wetter periods and higher LAI values. In a dry year, the intercropping sequestered 2.9 t C ha-1, which was equivalent to 8.0 kg C ha-1 d-1. This study showed strong seasonal fluctuations in maize-grass intercropping CO2 fluxes, due to seasonality of rainfall, and that this agroecosystem is vulnerable to low SWS, with significant reduction in CO2 uptake during these periods.

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Bulk partitioning the growing season net ecosystem exchange of CO2 in Siberian tundra reveals the seasonality of its carbon sequestration strength

Biogeosciences Discussions ◽

10.5194/bgd-9-13713-2012 ◽

2012 ◽

Vol 9 (10) ◽

pp. 13713-13742 ◽

Cited By ~ 3

Author(s):

B. R. K. Runkle ◽

T. Sachs ◽

C. Wille ◽

E.-M. Pfeiffer ◽

L. Kutzbach

Keyword(s):

Carbon Sink ◽

Ecosystem Respiration ◽

Growing Season ◽

New Method ◽

Apparent Temperature ◽

The Arctic ◽

Co2 Uptake ◽

Night Time ◽

Tundra Ecosystem ◽

Co2 Sink

Abstract. This paper evaluates the relative contribution of light and temperature on net ecosystem CO2 uptake during the 2006 growing season in a~polygonal tundra ecosystem in the Lena River Delta in Northern Siberia (72°22´ N, 126°30´ E). We demonstrate that the timing of warm periods may be an important determinant of the magnitude of the ecosystem's carbon sink function, as they drive temperature-induced changes in respiration. Hot spells during the early portion of the growing season are shown to be more influential in creating mid-day surface-to-atmosphere net ecosystem CO2 exchange fluxes than those occurring later in the season. In this work we also develop and present a bulk flux partition model to better account for tundra plant physiology and the specific light conditions of the arctic region that preclude the successful use of traditional partition methods that derive a respiration-temperature relationship from all night-time data. Night-time, growing season measurements are rare during the arctic summer, however, so the new method allows for temporal variation in the parameters describing both ecosystem respiration and gross uptake by fitting both processes at the same time. Much of the apparent temperature sensitivity of respiration seen in the traditional partition method is revealed in the new method to reflect seasonal changes in basal respiration rates. Understanding and quantifying the flux partition is an essential precursor to describing links between assimilation and respiration at different time scales, as it allows a more confident evaluation of measured net exchange over a broader range of environmental conditions. The growing season CO2 sink estimated by this study is similar to those reported previously for this site, and is substantial enough to withstand the long, low-level respiratory CO2 release during the rest of the year to maintain the site's CO2 sink function on an annual basis.

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Seasonal variations in carbon dioxide exchange in an alpine wetland meadow on the Qinghai-Tibetan Plateau

Biogeosciences ◽

10.5194/bg-7-1207-2010 ◽

2010 ◽

Vol 7 (4) ◽

pp. 1207-1221 ◽

Cited By ~ 59

Author(s):

L. Zhao ◽

J. Li ◽

S. Xu ◽

H. Zhou ◽

Y. Li ◽

...

Keyword(s):

Carbon Dioxide ◽

Tibetan Plateau ◽

Carbon Sink ◽

Ecosystem Respiration ◽

Gross Primary Production ◽

Carbon Dioxide Exchange ◽

Research Station ◽

Rain Event ◽

Area Index ◽

Alpine Wetland

Abstract. Alpine wetland meadow could functions as a carbon sink due to it high soil organic content and low decomposition. However, the magnitude and dynamics of carbon stock in alpine wetland ecosystems are not well quantified. Therefore, understanding how environmental variables affect the processes that regulate carbon fluxes in alpine wetland meadow on the Qinghai-Tibetan Plateau is critical. To address this issue, Gross Primary Production (GPP), Ecosystem Respiration (Reco), and Net Ecosystem Exchange (NEE) were examined in an alpine wetland meadow using the eddy covariance method from October 2003 to December 2006 at the Haibei Research Station of the Chinese Academy of Sciences. Seasonal patterns of GPP and Reco were closely associated with leaf area index (LAI). The Reco showed a positive exponential to soil temperature and relatively low Reco occurred during the non-growing season after a rain event. This result is inconsistent with the result observed in alpine shrubland meadow. In total, annual GPP were estimated at 575.7, 682.9, and 630.97 g C m−2 in 2004, 2005, and 2006, respectively. Meanwhile, the Reco were equal to 676.8, 726.4, 808.2 g C m−2, and thus the NEE were 101.1, 44.0 and 173.2 g C m−2. These results indicated that the alpine wetland meadow was a moderately source of carbon dioxide (CO2). The observed carbon dioxide fluxes in the alpine wetland meadow were higher than other alpine meadow such as Kobresia humilis meadow and shrubland meadow.

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Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan

Biogeosciences ◽

10.5194/bg-12-6837-2015 ◽

2015 ◽

Vol 12 (23) ◽

pp. 6837-6851 ◽

Cited By ~ 7

Author(s):

K. Yamanoi ◽

Y. Mizoguchi ◽

H. Utsugi

Keyword(s):

Forest Management ◽

Carbon Balance ◽

Deciduous Forest ◽

Carbon Sink ◽

Ecosystem Respiration ◽

Gross Primary Production ◽

Co2 Flux ◽

White Birch ◽

Eddy Covariance Method ◽

Area Index

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.

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Biophysical controls on net ecosystem CO2 exchange over a semiarid shrubland in northwest China

Biogeosciences Discussions ◽

10.5194/bgd-11-5089-2014 ◽

2014 ◽

Vol 11 (3) ◽

pp. 5089-5122 ◽

Cited By ~ 3

Author(s):

X. Jia ◽

T. S. Zha ◽

B. Wu ◽

Y. Q. Zhang ◽

J. N. Gong ◽

...

Keyword(s):

Ecosystem Respiration ◽

Growing Season ◽

C Sequestration ◽

Northwest China ◽

Wide Distribution ◽

Co2 Exchange ◽

Co2 Uptake ◽

Area Index ◽

C Cycling ◽

Sequestration Potential

Abstract. The carbon (C) cycling in semiarid and arid areas remains largely unexplored, despite the wide distribution of drylands globally. Rehabilitation practices have been carried out in many desertified areas, but information on the C sequestration potential of recovering vegetation is still largely lacking. Using the eddy-covariance technique, we measured the net ecosystem CO2 exchange (NEE) over a recovering shrub ecosystem in northwest China throughout 2012 in order to (1) quantify NEE and its components, (2) examine the dependence of C fluxes on biophysical factors at multiple timescales. The annual budget showed a gross ecosystem productivity (GEP) of 456 ± 8 g C m−2 yr−1 and an ecosystem respiration (Re) of 379 ± 3 g C m−2 yr−1, resulting in a net C sink of 77 ± 7 g C m−2 yr−1. The maximum daily NEE, GEP and Re were −4.7, 6.8 and 3.3 g C m−2 day−1, respectively. Both the maximum C assimilation rate (i.e., at optimum light intensity) and the quantum yield varied strongly over the growing season, being higher in summer and lower in spring and autumn. At the half-hourly scale, water stress exerted a major control over daytime NEE, and interacted with heat stress and photoinhibition in constraining C fixation by the vegetation. Low soil moisture also reduced the temperature sensitivity of Re (Q10). At the synoptic scale, rain events triggered immediate pulses of C release from the ecosystem, followed by peaks of CO2 uptake 1–2 days later. Over the entire growing season, leaf area index accounted for 45 and 65% of the seasonal variation in NEE and GEP, respectively. There was a linear dependence of daily Re on GEP, with a slope of 0.34. These results highlight the role of abiotic stresses and their alleviation in regulating C cycling in the face of an increasing frequency and intensity of extreme climatic events.

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Influence of the Asian Monsoon on net ecosystem carbon exchange in two major plant functional types in Korea

Biogeosciences Discussions ◽

10.5194/bgd-6-10279-2009 ◽

2009 ◽

Vol 6 (6) ◽

pp. 10279-10309 ◽

Cited By ~ 4

Author(s):

H. Kwon ◽

J. Kim ◽

J. Hong

Keyword(s):

Summer Monsoon ◽

Carbon Sink ◽

Ecosystem Respiration ◽

Gross Primary Production ◽

Co2 Exchange ◽

Plant Functional Types ◽

Net Ecosystem Co2 Exchange ◽

Area Index ◽

Functional Types ◽

Net Ecosystem Carbon Exchange

Abstract. Considering the feedback loops in radiation, temperature, and soil moisture with alterations in rainfall patterns, the influence of the changing monsoon on net ecosystem CO2 exchange can be critical to the estimation of carbon balance in Asia. In this paper, we examined the eddy covariance CO2 fluxes observed from 2004 to 2008 in two major plant functional types in KoFlux, i.e., the Gwangneung deciduous forest (GDK) site and the Haenam farmland (HFK) site. The objectives of the study were to (1) quantify the net ecosystem CO2 exchange (NEE), ecosystem respiration (RE), and gross primary production (GPP), (2) examine their interannual patterns, and (3) assess the mechanism for the coupling of carbon and water exchange associated with the summer monsoon. The GDK site, which had a maximum leaf area index (LAI) of ~5, was on average a relatively weak carbon sink with NEE of −84 gC m−2 y−1, RE of 1028 gC m−2 y−1, and GPP of 1113 gC m−2 y−1. Despite about 20% larger GPP (of 1321 gC m−2 y−1) in comparison with the GDK site, the HFK site (with the maximum LAI of 3 to 4) was a weaker carbon sink with NEE of −58 gC m−2 y−1 because of greater RE of 1263 gC m−2 y−1. In both sites, the annual patterns of NEE and GPP had a striking "mid-season depression" each year with two distinctive peaks of different timing and magnitude, whereas RE did not. The mid-season depression at the GDK site occurred typically from early June to late August, coinciding with the season of summer monsoon when the solar radiation decreased substantially due to frequent rainfalls and cloudiness. At the HFK site, the mid-season depression began earlier in May and continued until the end of July due to land use management (e.g., crop rotation) in addition to such disturbances as summer monsoon and typhoons. Other flux observation sites in East Asia also show a decline in radiation but with a lesser degree during the monsoon season, resulting in less pronounced depression in NEE. In our study, however, the observed depression in NEE changed the forest and farmland from a carbon sink to a source in the middle of the growing season. Consequently, the annually integrated values of NEE lies on the low end of the range reported in the literature. Such a delicate coupling between carbon and water cycles may turn these ecosystems into a stronger carbon sink with the projected trends of less frequent but more intensive rainfalls in this region.

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Response of hydrology and CO2 flux to experimentally altered rainfall frequency in a temperate poor fen, southern Ontario, Canada

Biogeosciences ◽

10.5194/bg-15-3937-2018 ◽

2018 ◽

Vol 15 (13) ◽

pp. 3937-3951

Author(s):

Danielle D. Radu ◽

Tim P. Duval

Keyword(s):

Carbon Sink ◽

Ecosystem Respiration ◽

Moisture Regime ◽

Co2 Uptake ◽

Vegetation Types ◽

Precipitation Frequency ◽

Near Surface ◽

Poor Fen ◽

Rainfall Frequency ◽

Strong Control

Abstract. Predicted changes to the precipitation regime in many parts of the world include intensifying the distribution into lower frequency, large magnitude events. The corresponding alterations to the soil moisture regime may affect plant growth and soil respiration, particularly in peatlands, where large stores of organic carbon are due to gross ecosystem productivity (GEP) exceeding ecosystem respiration (ER). This study uses lab monoliths corroborated with field measurements to examine the effect of changing rainfall frequency on peatland moisture controls on CO2 uptake in an undisturbed cool temperate poor fen. Lab monoliths and field plots containing mosses, sedges, or shrubs received either 2.3, 1, or 0.5 precipitation events per week, with total rainfall held constant. Decreasing rain frequency led to lower near-surface volumetric moisture content (VMC), water table (WT), and soil tension for all vegetation types, with minimal effect on evapotranspiration. The presence of sedges in particular led to soil tensions of ≥100 cm of water for a sizeable duration (37 %) of the experiment. Altered rainfall frequencies affected GEP but had little effect on ER; overall, low-frequency rain led to a reduced net CO2 uptake for all three vegetation types. VMC had a strong control on GEP and net ecosystem exchange (NEE) of the Sphagnum capillifolium monoliths, and decreasing rainfall frequency influenced these relationships. Overall, communities dominated by mosses became net sources of CO2 after 3 days without rain, whereas sedge communities remained net sinks for up to 14 days without rain. The results of this study demonstrate the hydrological controls of peatland CO2 exchange dynamics influenced by changing precipitation frequency; furthermore, they suggest these predicted changes in frequency will lead to increased sedge GEP but limit the carbon-sink function of peatlands.

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Monitoring Key Forest Structure Attributes across the Conterminous United States by Integrating GEDI LiDAR Measurements and VIIRS Data

Remote Sensing ◽

10.3390/rs13030442 ◽

2021 ◽

Vol 13 (3) ◽

pp. 442

Author(s):

Khaldoun Rishmawi ◽

Chengquan Huang ◽

Xiwu Zhan

Keyword(s):

Forest Structure ◽

Infrared Imaging ◽

Carbon Sink ◽

3D Structure ◽

Three Dimensional ◽

Tree Height ◽

Ecosystem Dynamics ◽

Accurate Information ◽

Area Index ◽

Plant Area Index

Accurate information on the global distribution and the three-dimensional (3D) structure of Earth’s forests is needed to assess forest biomass stocks and to project the future of the terrestrial Carbon sink. In spite of its importance, the 3D structure of forests continues to be the most crucial information gap in the observational archive. The Global Ecosystem Dynamics Investigation (GEDI) Light Detection and Ranging (LiDAR) sensor is providing an unprecedented near-global sampling of tropical and temperate forest structural properties. The integration of GEDI measurements with spatially-contiguous observations from polar orbiting optical satellite data therefore provides a unique opportunity to produce wall-to-wall maps of forests’ 3D structure. Here, we utilized Visible Infrared Imaging Radiometer Suite (VIIRS) annual metrics data to extrapolate GEDI-derived forest structure attributes into 1-km resolution contiguous maps of tree height (TH), canopy fraction cover (CFC), plant area index (PAI), and foliage height diversity (FHD) for the conterminous US (CONUS). The maps were validated using an independent subset of GEDI data. Validation results for TH (r2 = 0.8; RMSE = 3.35 m), CFC (r2 = 0.79; RMSE = 0.09), PAI (r2 = 0.76; RMSE = 0.41), and FHD (r2 = 0.83; RMSE = 0.25) demonstrated the robustness of VIIRS data for extrapolating GEDI measurements across the nation or even over larger areas. The methodology developed through this study may allow multi-decadal monitoring of changes in multiple forest structural attributes using consistent satellite observations acquired by orbiting and forthcoming VIIRS instruments.

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Measuring A Fire: The Story of the January 2019 Fire Told from Measurements at the Warra Supersite, Tasmania

Fire ◽

10.3390/fire4020015 ◽

2021 ◽

Vol 4 (2) ◽

pp. 15

Author(s):

Tim Wardlaw

Keyword(s):

Vegetation Change ◽

Carbon Sink ◽

Natural Disturbance ◽

Weather Conditions ◽

Permanent Plots ◽

Ground Vegetation ◽

Area Index ◽

Forest Fire Danger ◽

Eucalypt Forests ◽

Fine Fuels

Non-stand-replacing wildfires are the most common natural disturbance in the tall eucalypt forests of Tasmania, yet little is known about the conditions under which these fires burn and the effects they have on the forest. A dry lightning storm in January 2019 initiated the Riveaux Road fire. This fire burnt nearly 64,000 ha of land, including tall eucalypt forests at the Warra Supersite. At the Supersite, the passage of the fire was recorded by a suite of instruments measuring weather conditions and fluxes (carbon, water and energy), while a network of permanent plots measured vegetation change. Weather conditions in the lead-up and during the passage of the fire through the Supersite were mild—a moderate forest fire danger index. The passage of the fire through the Supersite caused a short peak in air temperature coinciding with a sharp rise in CO2 emissions. Fine fuels and ground vegetation were consumed but the low intensity fire only scorched the understorey trees, which subsequently died and left the Eucalyptus obliqua canopy largely intact. In the aftermath of the fire, there was prolific seedling regeneration, a sustained reduction in leaf area index, and the forest switched from being a carbon sink before the fire to becoming a carbon source during the first post-fire growing season.

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Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?