As the climate changes, plants adjust their characteristics to cope with new environmental conditions. However, it’s not well understood whether tree planting affects how these adjustments happen across different areas. In this study, we compared the hydraulic traits (how trees move and store water) of trees in natural forests and planted forests across China. We found that planted forests have trees with better water safety but less efficient water use than trees in natural forests. Interestingly, in natural forests, there is a trade-off between water efficiency and safety, while in planted forests, these two traits seem to improve together. Both environmental factors (like weather) and ecological factors (such as tree age and height) affect these water traits, but the main influences vary. Looking ahead, we predict that both types of forests will become better at using water and resisting drought as a response to increasing rainfall and drier air. These findings are important for understanding how forests might change with climate change and for improving models that predict how forests impact the carbon and water cycles.