(STUDY FINDS) – Could making neighborhoods greener be the secret to longer, healthier lives for residents? One long-term project that saw nearly 50,000 trees planted over three decades in Portland shows a significant correlation between overall health and longevity among the surrounding population.

Between 1990 and 2019, an Oregon-based campaign called Friends of Trees added 49,246 trees to Portland’s streets and kept record of where and when they did so. Although there is existing evidence for an association between nature and reduced risk of death, prior research hasn’t been so reliable. “Most studies use satellite imaging to estimate the vegetation index, which does not distinguish different types of vegetation and cannot be directly translated into tangible interventions,” says Payam Dadvand, ISGlobal researcher and senior author of the study, in a media release.