Premium
The contribution of trees to ecosystem methane emissions in a temperate forested wetland
Author(s) -
Pangala Sunitha R.,
Hornibrook Edward R.C.,
Gowing David J.,
Gauci Vincent
Publication year - 2015
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12891
Subject(s) - wetland , environmental science , ecosystem , temperate climate , alnus glutinosa , temperate rainforest , temperate forest , ecology , atmospheric sciences , greenhouse gas , methane , forest ecology , flux (metallurgy) , hydrology (agriculture) , alder , biology , chemistry , geology , geotechnical engineering , organic chemistry
Wetland‐adapted trees are known to transport soil‐produced methane ( CH 4 ), an important greenhouse gas to the atmosphere, yet seasonal variations and controls on the magnitude of tree‐mediated CH 4 emissions remain unknown for mature forests. We examined the spatial and temporal variability in stem CH 4 emissions in situ and their controls in two wetland‐adapted tree species ( Alnus glutinosa and Betula pubescens ) located in a temperate forested wetland. Soil and herbaceous plant‐mediated CH 4 emissions from hollows and hummocks also were measured, thus enabling an estimate of contributions from each pathway to total ecosystem flux. Stem CH 4 emissions varied significantly between the two tree species, with Alnus glutinosa displaying minimal seasonal variations, while substantial seasonal variations were observed in Betula pubescens . Trees from each species emitted similar quantities of CH 4 from their stems regardless of whether they were situated in hollows or hummocks. Soil temperature and pore‐water CH 4 concentrations best explained annual variability in stem emissions, while wood‐specific density and pore‐water CH 4 concentrations best accounted for between‐species variations in stem CH 4 emission. Our study demonstrates that tree‐mediated CH 4 emissions contribute up to 27% of seasonal ecosystem CH 4 flux in temperate forested wetland, with the largest relative contributions occurring in spring and winter. Tree‐mediated CH 4 emissions currently are not included in trace gas budgets of forested wetland. Further work is required to quantify and integrate this transport pathway into CH 4 inventories and process‐based models.