The study measured the basic densities of 572 softwood trees from 10 species and 440 hardwood trees from 50 species to estimate the amount of carbon removal by forests, following guidelines from the Kyoto Protocol and Marrakesh Accord. Basic densities were averaged per species and 95% confidence limits were calculated for quality control. Variations in mean basic densities within species were analyzed, and the effects of stand age and tree age on basic densities were evaluated. Most species showed low uncertainty (up to 5%), with some species like Larix kaempferi, Picea jezoensis, and Picea gleichii showing significant differences between plots, while others like Chamaecyparis obtusa and Abies sachalinensis did not. When averaged regionally, no significant differences were found, suggesting that plot differences were not due to regional variation. Neither tree age nor stand age showed significant correlation with basic densities, and younger stands (under 20 years) did not differ significantly from older stands. These results suggest that basic density can be used as a parameter for estimating carbon removal without needing values for districts or age classes. The study also found that the basic densities of some species, like Thujopsis dolabrata var. hondae, varied significantly with stand age, indicating the need for further analysis. Overall, the study concluded that basic density is a reliable parameter for estimating carbon removal by forests, with low uncertainty in most species.The study measured the basic densities of 572 softwood trees from 10 species and 440 hardwood trees from 50 species to estimate the amount of carbon removal by forests, following guidelines from the Kyoto Protocol and Marrakesh Accord. Basic densities were averaged per species and 95% confidence limits were calculated for quality control. Variations in mean basic densities within species were analyzed, and the effects of stand age and tree age on basic densities were evaluated. Most species showed low uncertainty (up to 5%), with some species like Larix kaempferi, Picea jezoensis, and Picea gleichii showing significant differences between plots, while others like Chamaecyparis obtusa and Abies sachalinensis did not. When averaged regionally, no significant differences were found, suggesting that plot differences were not due to regional variation. Neither tree age nor stand age showed significant correlation with basic densities, and younger stands (under 20 years) did not differ significantly from older stands. These results suggest that basic density can be used as a parameter for estimating carbon removal without needing values for districts or age classes. The study also found that the basic densities of some species, like Thujopsis dolabrata var. hondae, varied significantly with stand age, indicating the need for further analysis. Overall, the study concluded that basic density is a reliable parameter for estimating carbon removal by forests, with low uncertainty in most species.