Previous research has outlined an array of public benefits provided by the urban forest, including benefits to the local environment, to public health, and to climate change mitigation. In light of these benefits, city governments and nonprofit organizations in the United States have initiated tree-planting programs to increase urban canopy cover. In many cities, it is nonprofit organizations that have led the charge in planting trees by providing low-cost trees to neighborhoods and engaging neighborhood residents in tree-planting and maintenance. Often these nonprofits articulate program goals beyond increasing canopy cover, including social objectives like improving community capacity. Previous work in urban forestry has hypothesized that tree-planting programs can increase community capacity by engaging the community and providing a venue for community members to interact, but until now there has been no empirical evaluation of whether these programs are actually associated with such social outcomes.

This paper presents the first attempt to describe the relationship between neighborhood participation in urban forestry efforts and the collective efficacy and shared trust in a neighborhood. This research leverages a unique dataset that includes both ecological and social information about tree-planting neighborhoods and matched comparison neighborhoods in five cities in the United States. The data include survey responses from residents and participants; interview responses from neighborhood leaders and nonprofit employees; a suite of neighborhood socio-demographic characteristics and a unique layer of spatial characteristics developed using a Geographic Information System. Data collection is occurring through the spring and summer of 2014. Several strategies have been taken to address selection issues, including the ex-ante selection of comparison neighborhoods using propensity score matching with matching restrictions on canopy cover, racial composition and income. Hierarchical regression techniques will account for spatial clustering of individuals within neighborhoods.

Preliminary results suggest that nonprofit tree planting programs that require neighborhood involvement have positive effects on the community, including facilitating neighbors to meet and communicate. This research serves as a first step in describing a causal relationship between a neighborhood’s participation in urban tree planting and community capacity. The results of this research will help inform future experimental research on the effects of these programs. In addition, findings speak to broader literature on collective action by demonstrating the relationship between community collective action, collective efficacy, and other neighborhood characteristics.