Leafy localities, longer lives: A cross-sectional and spatial analysis

Abstract

Are trees good for your health? Using detailed satellite imagery, we estimate the extent of tree coverage at a fine neighborhood level across urban Australia. We then look at the neighborhood-level association between tree canopy cover and mortality. Holding constant socioeconomic status, we find evidence of a strong beneficial relationship. Neighborhoods with more trees have lower levels of mortality, with a 10 percentage point increase in tree cover (about one standard deviation) associated with a reduction in mortality of 11 deaths per 100,000 people (about one eighth of a standard deviation). This association holds for most major causes of death, and is larger for men than for women. Health morbidity is better in areas with more trees, although this relationship is not statistically significant. Analysis of sub-samples does not support the critique that our results are merely driven by short-term selection effects in which healthier people move to tree-lined suburbs. Using standard estimates of the value of a statistical life, the mortality benefit of additional trees substantially exceeds the cost of planting and maintenance. Our findings support the protection and restoration of tree canopy in urban neighborhoods as a means of promoting public health and reducing health inequalities.