Assessment of soil carbon dioxide efflux in oak and Korean pine-broadleaf forests of the Southern Sikhote-Alin (Primorsky region, Russia)

Data on carbon dioxide emissions from soils in oak and Korean pine-broadleaf forests of the southern Sikhote-Alin were obtained during the 2023–2025 study period. Differences in the average monthly CO2 emission rates across seasons were characterized in the Haplic Cambisols of the investigated forest ecosystems. Forests growing under conditions of a temperate monsoon climate exhibit a specific soil respiration regime, characterized by a high proportion of summer flux (over 50%) and high emission values during the early autumn months. The highest parameters of total CO2 fluxes were observed in autumn (September, October), which is associated with favorable hydrothermal conditions for microflora activity during this period. The highest carbon losses over the study period were recorded in oak forests, amounting to 673.59 g C m⁻², while the annual total CO2 flux in Korean pine forests was 617.10 g C m⁻².