Alain Paquette and Rita Silva Sousa (PaqLab alumni) contributed to a massive review published in Current Forestry Reports. The purpose was to assess the scientific basis for promoting diverse plantations over monocultures in global afforestation and restoration efforts, particularly in the context of climate change. To do so, it examined the 428 peer-reviewed studies which utilize data from TreeDivNet (the largest global network of tree diversity experiments), covering 25 years’ worth of research. The review aimed to address three key questions: (i) How have TreeDivNet experiments contributed to understanding the relationship between tree diversity and performance? (ii) What knowledge gaps remain in this understanding? (iii) What practical insights can be gained for real-world forest plantations?

The study presents a conceptual framework that identifies various pathways linking tree performance to local diversity, emphasizing positive effects of species and functional diversity on productivity. While most studies focus on direct diversity effects, such as productivity, positive impacts on light uptake and disease resistance are noted in mixed plantations. The majority of experiments are in temperate forests, with limited representation of (sub)tropical and boreal forests. TreeDivNet supports the idea of mixing tree species to enhance productivity but acknowledges challenges in translating findings into practical management guidelines. Future research is suggested to fill knowledge gaps, identify optimal species mixtures, and develop management-oriented approaches for mixed plantings.

Congratulations to the massive collaborative effort and decades of research that this review represents!