In the context of human-induced changes in global biospheric processes, research on carbon cycling at the ‘atmosphere – plants – soil’ scale and the corresponding mathematical models are of substantial interest. In addition to the global analysis of the balance of carbon fluxes, specialists in soil science argue that closer attention should be given to the mathematical description of the gaseous phase of soils at the ‘local level’, taking into account the diversity of soils and their ‘life cycle’ conditions. Thus, it is the local experimental data that are the basis for conclusions about an area being mainly a source or a sink of carbon, about the effects of soil reclamation, permafrost thawing, etc. A mathematical model is suggested here for daily carbon dioxide production and transport in forest soils typical of Eastern Fennoscandia. The model performs a comparative quantitative analysis of the diffusion and convection components to estimate changes in soil respiration and transfer directions. An attempt is made to minimize the number of boundary value problem parameters to be estimated using experimental data.