Background: A recent study was conducted to evaluate tree volume, biomass, and carbon stock in Java, Special Region of Yogyakarta, Indonesia in the mixed plantation of Artocarpus heterophyllus. Forest acts as a source or sinks for atmospheric CO2 to catches from the atmosphere in different carbon pools by trees in a forest. It was improperly managed and Illegal activities were done. Methods: Sample trees were selected by a simple random sampling method in the study site and the elevation was recorded by GPS. Each sample tree height, diameter at (DBH) point, and crown cover were measured as a source of primary source data. Data were analyzed statistically and results were composed in excel, Sigma Plot, and Past software. Results: The results of the conducted study are, average tree basel area was 0.00063 ± 0.00016 m2, while tree volume was 0.0039 ± 0.0017 m3, although the average total tree biomass was 0.0033 ± 0.0014 tons. Still, the mean carbon stock was 0.0016 ± 0.00071 tons, and the average absorb CO2 was 0.0060 ± 0.0026 tons. The results also concluded, tree basel areas have a strong positive correlation with tree volume, the value of R2 is 0.9088, while for stem biomass and R2 value is 0.9966. The correlation of total biomass with a carbon stock and R2 is 1.000 while the correlation with absorbing carbon dioxide and R2 is 1.000. Objectives: Aims of the study to estimate the volume, stem, and total biomass, carbon stock, and absorb carbon dioxide and to expose the impact of basal area on tree volume and stem biomass and total biomass on carbon stocks and absorb carbon dioxide. The study concluded that it is needed to have Proper scientific management and proper utilization it can be significant measures to enhance the potential to stored and sink more carbon and control illegal activities.