Investigating Social-Ecological Linkages in Baltimore, MD: Environmental Stewardship, Green Stormwater Infrastructure, and Tree Canopy Change at the Neighborhood Level

Environmental stewardship organizations in Baltimore play important roles in taking care of the local environment through conservation, management, restoration, monitoring, education, and other efforts. These diverse activities were captured in Baltimore’s Stewardship Mapping and Assessment Project (STEW-MAP) surveys in 2011 and 2019. Despite previous research, knowledge gaps remain about the spatial and temporal dynamics of environmental stewardship groups and their relationships with elements of the built environment, such as green stormwater infrastructure (GSI) and tree canopy cover. Using spatial Bayesian regression, we examine how 1) voluntary GSI, 2) regulatory GSI, 3) tree canopy cover, and 4) tree canopy cover change vary by the number of local stewardship organizations related to stormwater management or trees, with and without controlling for impervious surface cover, median household income, race, ethnicity, and vacant housing. Voluntary GSI represents bottom-up community initiatives and was expected to be more strongly predicted by stewardship than regulatory GSI, which is implemented in a top-down manner by City agencies. Tree canopy cover and canopy change are the product of both bottom up and top-down tree planting, protection, and maintenance activities. Overall, the number of stewardship groups from either point in time was not a significant predictor of tree canopy or GSI of either type. However, 2011 tree stewardship groups were positively associated with tree canopy gain from 2013 to 2018, and 2019 tree stewardship groups were slightly negatively associated with tree canopy change. Adjusted models showed impervious surface was positively related to voluntary GSI, median household income was positively associated with tree canopy cover, and percent Black/African American was negatively associated with regulatory GSI. The findings raise questions about how stewardship activities are quantified and mapped, and the other plausible mechanisms that explain the spatial distribution of GSI and tree canopy cover. More long-term quantitative data, augmented with qualitative, engaged and process-based inquiry might be needed to more holistically understand local stewardship motivations and actions and the potential outcomes of the myriad groups who care for their neighborhoods.