We compared soil properties and water storage capacity across these three forest types, finding that conversion from primary forests significantly reduced water retention capacity. While secondary forests exhibited better water retention than rubber plantations in shallow soil layers, they showed weaker capacity in deeper soils, with distinct seasonal variations in water storage. Soil porosity was identified as the key determining factor, with primary forests maintaining higher porosity.

Forest age is critical for carbon cycle modeling and effective forest management. Existing datasets, however, have low spatial resolutions or limited temporal coverage. This study introduces China's annual forest age dataset (CAFA), spanning 1986–2022 at a 30 m resolution. By tracking forest disturbances, we annually update ages. Validation shows small errors for disturbed forests and larger errors for undisturbed forests. CAFA can enhance carbon cycle modeling and forest management in China.