Soil greenhouse gas emissions from a managed forest in Acre

Forest management is an important economic activity of the state of Acre, southwest of Brazilian Amazon, but there are few studies on its effects on soil greenhouse gas (GHG) emissions. This work was carried out in the Antimary State Forest, Bujari municipality, to investigate the soil GHG emissions in a tropical forest area logged 16 years ago. The samples were collected with four field replications by closed chamber technique in the morning on three days in April 2023 and analyzed by gas chromatography to carbon dioxide - CO₂, methane - CH₄ and nitrous oxide - N₂O. Five sites were evaluated: log dump, forest road, trail, clearing and native forest. The fluxes of each individual gas were converted to daily mean of equivalent carbon dioxide - CO₂e. The highest soil fluxes were in the native forest (1.8±0.2 kg CO₂e ha^-1 day^-1) and the lowest in the log dump (0.4±0.2 kg CO₂e ha^-1 day^-1), while forest road (1.2±0.1 kg CO₂e ha^-1 day^-1), trail (1.6±0.1 kg CO₂e ha^-1 day^-1), and clearing (1.4±0.2 kg CO₂e ha^-1 day^-1) presented intermediary fluxes. The highest CO₂e may be associated with the greater microbiological activity in environments undisturbed by forest management as native forest. The lowest flux in the log dump is due the high degree of soil compaction in this location, as well as its expected low nitrogen content.