Short term effect of clear-felling on greenhouse gas emissions from naturally wet organic and mineral soils

Clear-felling, a predominant method for forest regeneration in areas with wet soils, has profound implications for greenhouse gas (GHG) emissions. This technique, by removing the forest cover, exposes the soil to increased sunlight, which can raise soil temperatures and enhance decomposition rates. Consequently, this process can significantly boost the emissions of carbon dioxide (CO2) and nitrous oxide (N2O). The absence of canopy cover also impacts soil moisture due to the decrease in plant transpiration, potentially leading to conditions that promote anaerobic processes in wet soils, thereby increasing methane (CH4) emissions. We monitored soil GHG (CO2, CH4, N2O) emissions in clear-felling sites before and after the harvesting. The study findings reveal a notable increase in CO2 emissions following the harvest, with an average rise of 226 mg CO2·m-2·h-1, representing a 120% increase. The CO2 emissions from mineral and organic soils did not significantly differ. While clear-felling had minimal impact on CH4 emissions from mineral soils, emissions from organic soils saw approximately a sixfold increase. Meanwhile, N2O emissions remained largely unchanged in both soil types post-clear-felling. When converted to CO2 equivalents, the emission results reveal a significant elevation in GHG emissions post-clear-felling, particularly from organic soils which witnessed a near threefold increase, whereas emissions from mineral soils roughly doubled. The study results highlight the implications of even-aged forest management strategies on wet soil GHG emissions.