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Research article2008Peer reviewed

Response of soil surface CO2 flux in a boreal forest to ecosystem warming

Bronson, Dustin R.; Gower, Stith T.; Tanner, Myron; Linder, Sune; Van Herk, Ingrid

Abstract

Soil surface carbon dioxide (CO2) flux (R-S) was measured for 2 years at the Boreal Soil and Air Warming Experiment site near Thompson, MB, Canada. The experimental design was a complete random block design that consisted of four replicate blocks, with each block containing a 15 m x 15 m control and heated plot. Black spruce [Picea mariana (Mill.) BSP] was the overstory species and Epilobium angustifolium was the dominant understory. Soil temperature was maintained (similar to 5 degrees C) above the control soil temperature using electric cables inside water filled polyethylene tubing for each heated plot. Air inside a 7.3-m-diameter chamber, centered in the soil warming plot, contained approximately nine black spruce trees was heated similar to 5 degrees C above control ambient air temperature allowing for the testing of soil-only warming and soil+air warming. Soil surface CO2 flux (R-S) was positively correlated (P < 0.0001) to soil temperature at 10 cm depth. Soil surface CO2 flux (R-S) was 24% greater in the soil-only warming than the control in 2004, but was only 11% greater in 2005, while R-S in the soil+air warming treatments was 31% less than the control in 2004 and 23% less in 2005. Live fine root mass (< 2 mm diameter) was less in the heated than control treatments in 2004 and statistically less (P < 0.01) in 2005. Similar root mass between the two heated treatments suggests that different heating methods (soil-only vs. soil+air warming) can affect the rate of decomposition.

Keywords

black spruce; carbon cycling; climate change; global warming; Picea mariana; Q(10); soil CO2 flux; soil temperature acclimation

Published in

Global Change Biology
2008, Volume: 14, number: 4, pages: 856-867
Publisher: BLACKWELL PUBLISHING

    UKÄ Subject classification

    Forest Science

    Publication identifier

    DOI: https://doi.org/10.1111/j.1365-2486.2007.01508.x

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/18968