Can artificial reforestation always be a forest climatic project?

Currently, forest climatic projects aimed at enhancing the carbon sequestration in forest ecosystems are becoming very popular. The main requirements for such projects include additionality, permanence and the absence of leakage. Compliance with these requirements ensures that the project fulfils the tasks at which it is aimed. Predictive modelling can be one of the tools for checking the compliance of forest climate projects with the above principles. The purpose of the study was to assess the prospects for carbon accumulation during the implementation of reforestation projects in the Krasnoyarsk and Irkutsk regions. An assessment of the carbon balance in the territory of artificial reforestation projects was carried out at the baseline (natural regeneration of Betula spp. and Populus tremula L.) and during the implementation of the forest climatic project (planting of Pinus sylvestris L.) with a forecast for 100 years. The results show that during the implementation of the project, the achieved level of emissions is higher and the level of carbon sequestration is lower compared to the baseline, which contradicts the principle of additionality, and, therefore, artificial reforestation cannot be considered as a forest climatic project. The highest efficiency in carbon sequestration for mixed plantations is predicted for mixtures of Pinus sylvestris with 20–30 percent of small-leaved species (Betula spp. and Populus tremula). However, the implementation of artificial reforestation projects can be essential for the reproduction of valuable forest resources, but in this case it is necessary to take into account the way the obtained phytomass of trees is used, since the length of the carbon conservation period will depend on this.