ABSTRACT.- The global rise in afforestation highlights the need for improved forestry practices, underscoring the demand for enhanced management strategies and research. Integrated intercropping systems offer sustainable solutions, promoting biodiversity and ecosystem health. This research explored the long-term effects of weed control and row spacing on eucalyptus (Eucalyptus grandis) and pinus (Pinus taeda), intercropped with switchgrass (Panicum virgatum), within a Uruguayan setting. Using spatiotemporal mixed models, we aimed to improve experimental accuracy and understand the dynamics between stand growth and agroforestry management. Significant impacts of spacing and weed control were found on both wood volume per hectare and individual volume. Optimal results per hectare were achieved with a 7-m row spacing for both species at the hectare level, while a 12-m spacing was more favorable for individual tree sizes. Low and medium weed control affected per tree and hectare wood volume productivity. Significant differences in switchgrass productivity were found between high and low weed control in pinus. The use of spatiotemporal structures has resulted in a better fit for the models in all cases, and it is noteworthy to consider the heterogeneous variances over the years. This study underscores the value of spatiotemporal analysis in agroforestry experimentation, integrating heterogeneous structures with temporal dynamics. These insights advance agroforestry by optimizing productivity and sustainability, offering adaptable strategies for regions sharing similar environmental profiles. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.