TY - JOUR

T1 - Controls on methane emissions from Alnus glutinosa saplings

AU - Pangala, Sunitha Rao

AU - Gowing, David J. G.

AU - Hornibrook, Edward R. C.

AU - Gauci, Vincent

PY - 2014/2

Y1 - 2014/2

N2 - Recent studies have confirmed significant tree-mediated methane emissions in wetlands; however, conditions and processes controlling such emissions are unclear. Here we identify factors that control the emission of methane from Alnus glutinosa.Methane fluxes from the soil surface, tree stem surfaces, leaf surfaces and whole mesocosms, pore water methane concentrations and physiological factors (assimilation rate, stomatal conductance and transpiration) were measured from 4-yr old A. glutinosa trees grown under two artificially controlled water-table positions.Up to 64% of methane emitted from the high water-table mesocosms was transported to the atmosphere through A. glutinosa. Stem emissions from 2 to 22 cm above the soil surface accounted for up to 42% of total tree-mediated methane emissions. Methane emissions were not detected from leaves and no relationship existed between leaf surface area and rates of tree-mediated methane emissions. Tree stem methane flux strength was controlled by the amount of methane dissolved in pore water and the density of stem lenticels.Our data show that stem surfaces dominate methane egress from A. glutinosa, suggesting that leaf area index is not a suitable approach for scaling tree-mediated methane emissions from all types of forested wetland.

AB - Recent studies have confirmed significant tree-mediated methane emissions in wetlands; however, conditions and processes controlling such emissions are unclear. Here we identify factors that control the emission of methane from Alnus glutinosa.Methane fluxes from the soil surface, tree stem surfaces, leaf surfaces and whole mesocosms, pore water methane concentrations and physiological factors (assimilation rate, stomatal conductance and transpiration) were measured from 4-yr old A. glutinosa trees grown under two artificially controlled water-table positions.Up to 64% of methane emitted from the high water-table mesocosms was transported to the atmosphere through A. glutinosa. Stem emissions from 2 to 22 cm above the soil surface accounted for up to 42% of total tree-mediated methane emissions. Methane emissions were not detected from leaves and no relationship existed between leaf surface area and rates of tree-mediated methane emissions. Tree stem methane flux strength was controlled by the amount of methane dissolved in pore water and the density of stem lenticels.Our data show that stem surfaces dominate methane egress from A. glutinosa, suggesting that leaf area index is not a suitable approach for scaling tree-mediated methane emissions from all types of forested wetland.

U2 - 10.1111/nph.12561

DO - 10.1111/nph.12561

M3 - Journal article

VL - 201

SP - 887

EP - 896

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 3

ER -