This study investigates the diversity and stability of agroforestry systems (AGSs) across three distinct ecological regions in Iran: the semi-arid Arasbaran, the semi-humid Zagros, and the humid Hyrcanian regions. The research aims to understand how climate impacts species richness and diversity within these systems. Data was collected from 129 farms, where species identification and various quantitative metrics, such as tree diameter and height, were measured. Biodiversity indices including Taxa_S, Shannon_H, and Equitability_J were calculated, and the species distribution was analyzed using parametric models. The results indicate significant differences in species richness and diversity across the three regions. The humid region exhibited the highest diversity, with 22 species from 10 families, whereas the semi-arid region showed the lowest diversity. The Shannon and Taxa_S indices were also significantly higher in the humid region compared to the other two regions, suggesting that the humid climate supports a wider range of species. Conversely, the semi-arid region had the highest average tree volume, possibly due to the dominance of certain species better adapted to the harsh climate. The study also found that the semi-arid and semi-humid regions corresponded to geometric and broken stick models, respectively, indicating different levels of community stability. The findings suggest that AGSs in semi-humid regions are more stable than those in semi-arid regions, likely due to more favorable climatic conditions. This research highlights the importance of considering regional climatic factors in the development and management of AGSs to optimize biodiversity conservation and agricultural productivity.