Forestry and forest restoration are promising activities to mitigate climate change, as forests have a high capacity to sequester carbon in a short period of time. Mixed tree plantations for sustainable timber production can be a viable and scalable strategy to reconcile economic and environmental benefits and reduce the vulnerability of plantations to climate change. However, despite scientific evidence on the advantages of mixed tree plantations, conventional monocultures still prevail globally. Expanding mixed plantations depends on the decision makers preferences, which requires more than ecological and scientifical evidence of plantation performance. Here, our aim was to analyze the main barriers and opportunities to expand more sustainable mixed plantations in southeastern Brazil and southwestern France. In order to support policies and incentives to adapt forestry to climate change and increasing environmental demands. We identified the factors that govern landowners and forest managers decisions about mixed plantations based on a qualitative research method, developed through semi-structured focal interviews to identify the main barriers and possible future solutions, based on their experiences. The main barriers identified were: Dealing with species competition/dominance effect; Need for a genetic improvement program; Higher operating costs; and lack of technical knowledge. And the solutions presented were divided into three levels of mixtures: Level 1: Mixtures of clones - more common where there are massive Eucalyptus plantations, level 2: Mosaics of different species (landscape level), and level 3: At least 2 species in the same plot. We provide a basis for potential alternatives to promote mixed planting of trees in forestry, thus increasing the resilience of forests to climate change, in addition to their ability to provide multiple benefits to nature and people.