This study systematically evaluates the carbon stock dynamics in the Qinling Mountain forest ecosystem of Shaanxi Province,utilizing the 2023 integrated monitoring dataset of forest-grassland ecosystems and the latest resource inventory data,and following the calculation methods in the Forest Ecosystem Carbon Stock Measurement Guidelines(LY/T 2988—2018).The results show that:1) Quercus spp.is the absolute dominant tree species in the region,accounting for 76.21%,followed by Pinus tabuliformis,accounting for about 12.84%.In terms of age groups,middle-aged forests have the highest proportion,at 46.55%,while mature forests have the lowest proportion,at 22.53%.2) The total carbon storage of arbor forest land is 193.37 Tg,among which Quercus spp.and Pinus tabuliformis forests have the largest carbon storage,accounting for 79.43% and 8.67% of the total carbon storage of arbor forest land,respectively.Middle-aged forests account for 48.84% of the carbon storage,while young and mature forests account for 22.93% and 28.24%,respectively.3) The average stand carbon density of dominant tree species was 43.49 Mg/hm²,with Quercus spp.and Pinus tabuliformis forests averaging 45.22 and 29.29 Mg/hm²,respectively.Overall,tree species carbon density in the region showed an increasing trend with stand age.4) The total carbon storage of the forest ecosystem is 531.09 Tg,among which the tree layer,shrub layer,and soil layer account for 36.41%,7.59%,and 52.46% of the total carbon storage,respectively,the herb layer,litter and dead wood together account for 3.54%.