Residents in US cities are exposed to high levels of stress and violent crime. At the same time, a number of cities have put forward “greening” efforts which may promote nature’s calming effects and reduce stressful stimuli. Previous research has shown that greening may lower aggressive behaviors and violent crime. In this study we examined, for the first time, the longitudinal effects over a 30-year period of average city greenness on homicide rates across 290 major cities in the US, using multilevel linear growth curve modeling. Overall, homicide rates in US cities decreased over this time-period (52.1–33.5 per 100,000 population) while the average greenness increased slightly (0.41–0.43 NDVI). Change in average city greenness was negatively associated with homicide, controlling for a range of variables (β = −.30, p-value = .02). The results of this study suggest that efforts to increase urban greenness may have small but significant violence-reduction benefits.

美国城市的居民面临着高度的压力和暴力犯罪。与此同时，一些城市提出了“绿化”工作，可以促进自然的镇静效果，减少压力刺激。先前的研究表明，绿化可能会降低攻击性行为和暴力犯罪。在这项研究中，我们首次使用多级线性增长曲线模型研究了 30 年期间平均城市绿化对美国 290 个主要城市凶杀率的纵向影响。总体而言，美国城市的凶杀率在此期间下降（每 100,000 人口 52.1-33.5），而平均绿化率略有增加（0.41-0.43 NDVI）。控制一系列变量（β = -.30，p-值 = .02）。这项研究的结果表明，增加城市绿化的努力可能对减少暴力产生小而显着的好处。