Urban trees are a matter of life and death

Urban trees make our cities more beautiful, and they also provide a range of well-understood benefits such as carbon sequestration, reduced summertime cooling costs, and higher property values. However, trees do something more important: they make our cities healthy places to live. These health benefits begin even before we are born, as mothers with more trees around their homes are less likely to have underweight babies. Planting trees is also associated with reduced human mortality. Conversely, loss of trees—from invasive pests—is associated with increased mortality. Finally, it is not just the number of trees that are important. Emerging research suggests that when people are exposed to more diverse trees and plants, their immune systems function better, and they are less likely to suffer from immune diseases such as asthma and childhood leukemia.