Objective This paper analyzed the distribution characteristics of moisture contents of 12 tree species in northeastern China and species-specific allometric equations of 12 tree species were established to explore the differences in water storage capacity characteristics among different tree species with forest developing, as well as providing model reference for the estimation of water storage capacity in this area.

Method One-way ANOVA and multiple comparison methods were used to contrast differences in moisture content and water storage capacity proportion among various organs across the 12 tree species. Utilizing Kendall’s rank correlation analysis to identify DBH (D), tree height (H), and D²H as predictor variables in water storage capacity prediction models with whole-tree and organ-specific water storage capacity serving as response variables. Different forms of water storage capacity prediction models were constructed based on these relationships. Optimal models were selected through evaluation using the coefficient of determination, parameter significance level, and Akaike’s information criterion. Integrating stand information, this approach was employed to calculate the water storage capacity of trees across varied developing stages.

Result (1) Overall, average moisture content was highest in leaves, followed by roots, branches, and stems. Except for Carpinus cordata, all other species showed a consistent pattern in water allocation across organs: stem > root > branch > leaf. As D increased, the proportion of branch water storage capacity increased, while the proportion of stem and leaf water storage capacity decreased, with no significant changes in root water storage capacity. (2) The water storage capacity prediction models for all 12 tree species were best represented by logarithmic functions. The optimal independent variables for organ moisture content models of different tree species were different. (3) With forest succession, both water storage capacity and biomass per unit area increased.

Conclusion The study highlights significant differences in water storage capacity and distribution among organs and tree species, with species-specific relationship between water storage capacity and D, as well as H. The percentage of water storage capacity of different organs shows different trends with the increase of breast diameter. The water content prediction models for all 12 tree species were best represented by logarithmic functions. The single-species models have higher fitting accuracy, while the multi-species model has broader application. This research elucidates the spatiotemporal dynamics of water status in temperate-boreal tree species, contributing to a deeper understanding of ecosystem dynamics. It provides a scientific basis for accurate estimation of tree water storage capacity in the forest region of Jiaohe, Jilin Province of northeastern China.