Abstract
Abstract. Forest management practices can alter soil conditions, affecting the consumption and production processes that control soil methane (CH4) exchange. We studied the short-term effects of thinning, clear-cutting and stump harvesting on the CH4 exchange between soil and atmosphere at a boreal forest site in central Sweden, using an undisturbed plot as the control. Chambers in combination with a high-precision laser gas analyser were used for continuous measurements. Both the undisturbed plot and the thinned plot were net sinks of CH4, whereas the clear-cut plot and the stump harvested plot were net CH4 sources. The CH4 uptake at the thinned plot was reduced in comparison to the undisturbed plot. The shift from sink to source at the clear-cut and stump harvested plots was probably due to a rise in the water table and an increase in soil moisture, leading to lower gas diffusivity and more reduced conditions, which favour CH4 production by archea. Reduced evapotranspiration after harvesting leads to wetter soils, decreased CH4 consumption and increased CH4 production, and should be accounted for in the CH4 budget of managed forests.
Highlights
Methane (CH4) is the second most important carbon greenhouse gas, with a radiative forcing at least 25 times higher than carbon dioxide from a 100-year perspective (Shindell, et al, 2009)
The soil sink capacity is higher in forest soils than in grasslands and arable land (Dutaur and Verchot, 2007), and the global CH4 budget is sensitive to disturbances in forests
Our study on the short-term effects of boreal forest management on CH4 exchange shows that the undisturbed plot and the thinned plot remained net CH4 sinks, while the clearcut and stump harvested plots were net CH4 sources
Summary
Methane (CH4) is the second most important carbon greenhouse gas, with a radiative forcing at least 25 times higher than carbon dioxide from a 100-year perspective (Shindell, et al, 2009). Well-aerated forest soils are net sinks of atmospheric CH4 (Van Amstel, 2012). Consumption in soils is the second largest sink of CH4 after tropospheric oxidation by hydroxyl radicals with a global sink capacity estimated recently at 28–32 Tg CH4 yr−1 (Kirschke et al, 2013). The soil sink capacity is higher in forest soils than in grasslands and arable land (Dutaur and Verchot, 2007), and the global CH4 budget is sensitive to disturbances in forests. Conversion of natural forests to arable land, increased N deposition from the atmosphere and N fertilization of agricultural lands are estimated to have reduced the global CH4 soil sink by about 30 % between 1880 and 1980 (Ojima et al, 1993)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
