Technical Note: Semi-rigid chambers for methane gas flux measurements on tree stems

Siegenthaler, Andy; Welch, Bertie; Pangala, Sunitha Rao; Peacock, Mike; Gauci, Vincent

doi:10.5194/bg-13-1197-2016

Cited by 31 publications

(19 citation statements)

References 23 publications

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“…CH4 emissions from young and mature trees were measured across the plot, split into four transects within which the water table depths ranged from wet (0-10 m above the soil surface) to dry (0 1 m below the soil surface) conditions. Methane emissions from stems of mature and young trees were measured using static chambers as described by Pangala et al 7,18 and Siegenthaler et al 29 . Methane emissions (n = 207) were measured from aquatic surfaces within each plot, inside the flooded forests using floating chambers ( Supplementary Figure 1) deployed for 24 hours as described by Bastviken et al 30 .…”

Section: Ecosystem Scale Measurementsmentioning

confidence: 99%

Large emissions from floodplain trees close the Amazon methane budget

Pangala

Enrich‐Prast

Basso

et al. 2017

Nature

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238

272

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Wetlands are the largest global source of atmospheric methane (CH), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH in the tropics, consistently underestimate the atmospheric burden of CH determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH emissions. Here we report CH fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δC) of -66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a 'top-down' regional estimate of CH emissions of 42.7 ± 5.6 teragrams of CH a year for the Amazon basin, based on regular vertical lower-troposphere CH profiles covering the period 2010-2013. We find close agreement between our 'top-down' and combined 'bottom-up' estimates, indicating that large CH emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH source when trees are combined with other emission sources.

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Section: Ecosystem Scale Measurementsmentioning

confidence: 99%

Large emissions from floodplain trees close the Amazon methane budget

Pangala

Enrich‐Prast

Basso

et al. 2017

Nature

Self Cite

238

272

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“…total volume of the closed loop including chamber, clay ring, gas tubing, desiccant canister and internal volume of CRDS), a known concentration and volume of CH 4 was injected into the system in the laboratory and volume was calculated as a function of the increase in measured concentration; similar to that described by Siegenthaler et al . ().…”

Section: Methodsmentioning

confidence: 97%

Are methane emissions from mangrove stems a cryptic carbon loss pathway? Insights from a catastrophic forest mortality

et al. 2019

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Summary Growing evidence indicates that tree‐stem methane (CH4) emissions may be an important and unaccounted‐for component of local, regional and global carbon (C) budgets. Studies to date have focused on upland and freshwater swamp‐forests; however, no data on tree‐stem fluxes from estuarine species currently exist. Here we provide the first‐ever mangrove tree‐stem CH4 flux measurements from >50 trees (n = 230 measurements), in both standing dead and living forest, from a region suffering a recent large‐scale climate‐driven dieback event (Gulf of Carpentaria, Australia). Average CH4 emissions from standing dead mangrove tree‐stems was 249.2 ± 41.0 μmol m−2 d−1 and was eight‐fold higher than from living mangrove tree‐stems (37.5 ± 5.8 μmol m−2 d−1). The average CH4 flux from tree‐stem bases (c. 10 cm aboveground) was 1071.1 ± 210.4 and 96.8 ± 27.7 μmol m−2 d−1 from dead and living stands respectively. Sediment CH4 fluxes and redox potentials did not differ significantly between living and dead stands. Our results suggest both dead and living tree‐stems act as CH4 conduits to the atmosphere, bypassing potential sedimentary oxidation processes. Although large uncertainties exist when upscaling data from small‐scale temporal measurements, we estimated that dead mangrove tree‐stem emissions may account for c. 26% of the net ecosystem CH4 flux.

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“…Stem fluxes were only taken from one plot in Sabaju and one plot in Sebungan, due to time and resource limitations, adapting the chamber methodology used by Pangala et al (2013) and Siegenthaler et al (2016) to suit oil palms ( Figure 2B; Figure S1; Manning, 2019). Here, five palms were selected from each plot, including three that had soil collars next to them.…”

Section: Experimental Designmentioning

confidence: 99%

Carbon Emissions From Oil Palm Plantations on Peat Soil

Manning

Kho

Hill

et al. 2019

Front. For. Glob. Change

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Southeast Asian peatlands have undergone recent land use change with an increase in industrial agricultural plantations, including oil palm. Cultivating peatlands requires creating drainage ditches and other surface microforms (i.e., harvest paths, frond piles, cover plants, and next to the palm). However, it is currently unclear how these management actions affect rates of carbon losses from the peat. Here we report carbon fluxes from each of the different surface microforms measured monthly (soil CO 2 [total soil respiration-R tot ] and stem CH 4) and bimonthly (soil CH 4 , drain CO 2 and drain CH 4). We calculated annual carbon fluxes and partitioned heterotrophic (R h) and root-rhizosphere respiration by sampling rhizosphere and root-free soil. Linear mixed effect models were used to determine which environmental factors best-predicted carbon fluxes, and to develop recommendations for management solutions that could reduce carbon losses. Carbon fluxes varied significantly between the different microforms; the greatest CO 2 fluxes were measured next to the palm and the greatest CH 4 fluxes were measured from the drainage ditches. Annual estimates of R tot , R h and drain CO 2 were 22.08 ± 0.50, 17.75 ± 1.54, and 1.5 ± 0.10 Mg CO 2-C ha −1 yr −1 , respectively. R h varied between the two plantations: Sebungan averaged 11.43 ± 1.37 Mg CO 2-C ha −1 yr −1 and Sabaju averaged 24.08 ± 1.42 Mg CO 2-C ha −1 yr −1. Net ecosystem CH 4 fluxes averaged 61.02 ± 17.78 kg CH 4-C ha −1 yr −1-similar to unmanaged swamp forests. The two plantations did not vary in overall CH 4 flux, but did vary in transport pathway. CH 4 fluxes from the soil, drains and stems followed a ratio of 50:50:0 from Sabaju (water table depth [WTD]: −0.49 ± 0.004 m) and 11:98:0 from Sebungan (WTD: −0.77 ± 0.007 m). R h dominated the peat carbon losses. WTD controlled variation in R h from Sebungan where the WTD was deeper. Air and soil temperature controlled variation in Sabaju, with greater fluxes from the harvest path, attributed to the absence of shade. These results suggest that shading the soil (e.g., through addition of frond piles) and raising the water table may be the most effective ways to reduce peat carbon loss from drained peat soils.

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Technical Note: Semi-rigid chambers for methane gas flux measurements on tree stems

Cited by 31 publications

References 23 publications

Large emissions from floodplain trees close the Amazon methane budget

Large emissions from floodplain trees close the Amazon methane budget

Are methane emissions from mangrove stems a cryptic carbon loss pathway? Insights from a catastrophic forest mortality

Carbon Emissions From Oil Palm Plantations on Peat Soil

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