Many studies have found that living near a green space — land that is partly or completely covered with natural vegetation — is associated with health benefits, including lower blood pressure, reduced levels of stress and anxiety, and an increased sense of general wellbeing. Research has even linked green space with lower Medicare expenditures . What hasn’t been clear from these studies, however, is whether all types of green space confer the same benefits. Or are some green spaces potentially more healthful than others? A new study from Australia, published recently in JAMA Network Open , offers an answer. It found that although residents of neighborhoods with plenty of leafy trees tend to have higher levels of psychological health and well-being, the same isn’t true for people living in neighborhoods where the green space consists primarily of open areas of grass. In fact, people living in areas with higher percentages of bare grass tend to have higher levels of psychologic...