A novel resident outreach program improves street tree planting outcomes in Los Angeles

Abstract

Urban tree planting is a key climate change resilience strategy for many municipalities, but remains challenged by establishment mortality in semi-arid regions. Street trees offer shade benefits to adjacent structures and pavement, and enable public works departments to implement heat island reduction interventions to exposed communities. But in Los Angeles, resident approval and written agreement to water for 3–5 years is required to plant street trees in residential public rights of way. Historically, 10% of residents contacted agreed to adopt street trees, and 50% of trees planted survived. Community engagement strategies, shown to improve tree acceptance rates and survival elsewhere, had not been tested here. This mixed-methods evaluation of a street tree planting and public education project in 2018 evaluated a novel youth outreach strategy to engage residents. Regular watering was provided post-transplant for varying periods. Residents were surveyed and project partners were interviewed; tree health was assessed visually. Resident feedback on the engagement strategy was strongly positive. Residents surveyed demonstrated measured learning outcomes, and satisfaction with education was associated with improved tree survival. Project partners identified numerous co-benefits, primarily among youth educators, and revealed an increased capacity for future urban greening work. Univariate logistic regression identified tree species, weeks of watering, and drought exposure as predictors of tree health (p < .05), but in a multivariate model, only certain tree species were significant (p < .05). This evaluation identifies multiple strategies to inform future tree planting projects, increase street tree acceptance and establishment survival, and support community co-benefits.