A multilevel evaluation of the development and implementation of a promotora-led nature-based intervention

Background Latine communities in the U. S. face persistent barriers to mental health care, exacerbated by inequities and trauma, requiring accessible and culturally congruent care. Simultaneously, these communities also possess profound strengths. To address these needs, Transforming Internal Experiences for Resilience and Restoration through Acceptance (TIERRA), an intervention led by Community Health Workers (CHWs, promotoras in Spanish) that combines third-wave cognitive behavioral therapy with Forest Bathing, was co-developed. The purpose of this paper is to detail the collaborative processes of TIERRA’s intervention development and implementation, and to report initial contextual evaluation outcomes. Methods The subsequent pilot development and implementation was evaluated using the Practical Robust Implementation and Sustainability Model (PRISM) and the embedded Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework to assess capacity building, implementation, and preliminary outcomes. Results TIERRA was developed utilizing Community-Based Participatory Research (CBPR) to center local community needs and assets. Its pilot demonstrated high feasibility and engagement (86% completion rate; n = 43). Evaluation of the implementation process revealed strong adoption and sustainability. Contextual evaluation with qualitative insights on effectiveness revealed the cultivation of radical hope, and that healing occurred through individual, interpersonal, community, and environmental pathways. Quantitative effectiveness outcomes showed significant reductions in stress ( p = 0.026) and depression ( p = 0.031), and significant increases in sense of community ( p < 0.001) and sense of belongingness ( p = 0.009). Discussion TIERRA is a promising culturally relevant, CHW-led mental health intervention that promotes healing among Latine Americans. This study also shows that intervention development and implementation that centers community participation and attends to cultural contextual factors can build community capacity and is sustainable.