Implementing reforestation and forest restoration measures is the most effective way to counter desertification and land degradation in low-precipitation steppe regions. The study area, situated in Argalant soum, Tuv aimag, is a grassland that is strongly affected by desertification in the steppe area. From a phytogeographic perspective, the area is described as a Middle Khalkha semi-arid steppe (dry steppe) region. Selecting tree species that can adapt to the local environment is crucial for successful afforestation efforts. Fine roots were measured in sequential soil layers 0-40 cm depth increments across a total of 216 samples in the afforestation site, and 60 soil samples were collected in sequential layers from 0 to 60 cm in depth at the afforestation and control sites. This study showed that Hippophae rhamnoides had higher fine root biomass accumulation (1.689 g m(-2)), renewal rate (1.071 yr) and productivity (0.949 g m(-2)). For Populus sibirica and Ulmus pumila, their fine root development showed similar results. However, three different tree species accumulated different amounts of soil organic carbon. U. pumila (51.16 Mg ha(-1)) increased the soil carbon stock by one time compared to the other two species. It is necessary to select and plant tree species that have a significant impact on increasing fine-root biomass, productivity, soil fertility and soil organic carbon stocks in the arid steppe regions of Mongolia.