Impacts of stump harvesting on carbon dioxide, methane and nitrous oxide fluxes

Summary, in English

During 2010-2013, we investigated the effects of stump harvesting on greenhouse gas (GHG) fluxes of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) with the flux-gradient technique at four experimental plots in a hemiboreal forest in Sweden. All plots were clear-cut and soil scarified and two of the plots were additionally stump harvested. The two clear-cut plots served as control plots. Due to differences in topography, we had one wetter and one drier plot of each treatment. All plots exhibited substantial emissions of GHGs and we noted significant effects of wetness on CO₂, CH₄ and N₂O fluxes within treatments and significant effects of stump harvesting on CO₂ and N₂O fluxes at the dry plots. The CO₂ emissions were lower at the dry stump harvested plot than at the dry control, but when estimated emissions from the removed stumps were added, total CO₂ emissions were higher at the stump harvested plot, indicating a small enhancement of soil respiration. In addition, we noted significant emissions of N₂O at this plot. At the wet plots, CO₂ emissions were higher at the stump harvested plot, also suggesting a treatment effect but differences in wetness and vegetation cover at these plots make this effect more uncertain. At the wet plots, we noted sustained periods (weeks to months) of net N₂O uptake. During the year with simultaneous measurements of the abovementioned GHGs, GHG budgets were 1.224×10³ and 1.442×10³ gm^-2 of CO₂-equivalents at the wet and dry stump harvested plots, respectively, and 1.070×10³ and 1.696×10³ gm^-2 of CO₂-equivalents at the wet and dry control plots, respectively. CO₂ fluxes dominated GHG budgets at all plots but N₂O contributed with 17% at the dry stump harvested plot. For the full period 2010-2013, total carbon (CO₂+CH₄) budgets were 4.301×10³ and 4.114×10³ g m^-2 of CO₂-eqvivalents at the wet and dry stump harvest plots, respectively and 4.107×10³ and 5.274×10³ gm^-2 of CO₂-equivalents at the wet and dry control plots, respectively. Our results support recent studies suggesting that stump harvesting does not result in substantial increase in CO₂ emissions but uncertainties regarding GHG fluxes (especially N₂O) remain and more long-term measurements are needed before robust conclusions can be drawn.

• Author: Patrik Vestin; Meelis Mölder; N Kljun; Zhanzhang Cai; Abdulghani Hasan; Jutta Holst; Leif Klemedtsson; Anders Lindroth
• Department/s: Dept of Physical Geography and Ecosystem Science; ICOS Sweden; Centre for Environmental and Climate Science (CEC); BECC: Biodiversity and Ecosystem services in a Changing Climate; MERGE: ModElling the Regional and Global Earth system
• Publishing year: 2022-06
• Language: English
• Pages: 148-162
• Publication/Series: iForest - Biogeosciences and Forestry
• Volume: 15
• Issue: 3
• Links: http://dx.doi.org/10.3832/ifor4086-015
• Document type: Journal article
• Publisher: The Italian Society of Silviculture and Forest Ecology (SISEF)
• Topic: Physical Geography; Climate Research; Other Earth and Related Environmental Sciences
• Keywords: CH; Climate Change Mitigation; CO; Forest Management; Greenhouse Gas Budget; Hemiboreal Forest; NO; Stump Harvesting
• Status: Published