How tree canopy cover can reduce urban suicide attempts: A geospatial analysis of the moderating role of area deprivation

Abstract

A lack of knowledge about the benefits of urban trees on mental health is addressed by exploring the association between tree canopy coverage, suicide attempts and the levels of neighborhood deprivation. Although the positive association between tree canopy cover and mental health as well as a negative association between neighborhood socioeconomic status and suicide attempts are well-known, it remains largely unclear how both area deprivation and tree canopy cover can help predicting local suicide attempts. Using the local suicide records (n = 3442) between 2015 and 2019 in the city of Cincinnati, OH, we analyzed if the number of local suicide attempts was related to the tree canopy cover at the census block group level (n = 275). After adjusting for control variables, we found that as the deprivation level gets a one-percentage point higher, the number of attempted suicide rate significantly increases by 1.05 %, while a one-percentage point increase in tree canopy coverage significantly decreases the attempted suicide rate by 0.9 %. Additionally, the level of area deprivation showed a moderating effect on the association between overall tree canopy and attempted suicide. Our findings suggest that local tree canopy cover could be a useful tool to improve local mental health including suicide attempts. More importantly, the benefit of tree canopy cover was stronger in less disadvantaged areas than in highly disadvantaged areas, which provides a new insight that interventions to qualitatively improve green space may be important for improving mental health in left-behind areas as a form of environmental justice.