Background Artificial vegetation construction is one of the effective measures to increase land carbon sink and slow down atmospheric CO₂ concentration.

Methods In order to clarify the carbon sequestration effects of artificial shelter forests in the Three Gorges Reservoir area, five typical plantations including pure Cunninghamia lanceolate coniferous (L1), pure Pinus massoniana coniferous (L2), mixed coniferous forest (L3), mixed broad-leaved forest (L4), mixed coniferous and broad-leaved forest (L5) were selected as the research objects, the biomass model based on stand volume and correlation analysis were used to analyze the spatial structure, carbon density and its influencing factors.

Results 1) The 3 mixed forests in the study area were moderately mixed or above, the neighborhood comparison value ranged from 0.35 to 0.65, which was in the middle state. L2 and L3 were randomly distributed, while the other stands are in aggregate distribution. 2) The soil organic carbon of the five forest types ranged from 0.83 to 5.25 g/kg, and it was rich in L3 and L4. The carbon densities (259.13 t/hm²) of the artificial shelterbelts were up to the national average level, soil and vegetation were the main carbon sequestration modes. The carbon sequestration capacities of L2 and L5 stands were significant, and the carbon sequestration capacity of mixed forest was significantly better than that of pure forest in tree layer and litter layer. 3) The density of soil organic carbon was affected by soil bulk density and clay content, while the mingling degree, angular scale and neighborhood comparison had effects on the carbon density of tree layer.

Conclusions The carbon sequestration function of 5 artificial shelterbelts in the study area was promising, and the stand structure may regulate the carbon sequestration function. Therefore, the function of carbon sequestration can be brought into full play by adjusting the forest spatial structure to regulate the forest land resources.