Suicide and Homicide More Common with Limited Urban Tree Canopy Cover

Distribution of urban tree canopies is generally not uniform. Multiple variables have been shown to be associated with tree canopy cover, including violence, health, and general well-being. Herein we examine the relationship of tree cover with intentional deaths. Suicide, homicide, and tree cover data were examined by ZIP code for Louisville, a mid-sized city in Kentucky. Relationship between intentional death (suicide and homicide) and tree cover was examined with Poisson regression analysis. In both univariate and multivariate models, suicides (P < 0.0001 and P = 0.0005), homicides (P < 0.0001 and P = 0.03), and combination (P = 0.0541) were negatively associated with tree cover. In this exploratory study we have found that sparse canopy cover is associated with higher rates of intentional human death (both suicides and homicides). Given that suicides and homicides are relatively rare occurrences, these data suggest that larger samples be examined to confirm the relationship between intentional death and canopy cover.