The healing power of the forest After years of careful study, Li has found that spending time in a forest can reduce stress, anxiety, depression, and anger; strengthen the immune system; improve cardiovascular and metabolic health; and boost overall well-being. “Wherever there are trees, we are healthier and happier,” writes Li. And, he adds, it isn’t about exercising—like hiking or jogging—it’s simply about being in nature. Why would this be? It’s long been recognized that humans have a biological need to connect with nature. Some 20 years ago, American biologist E. O. Wilson noted that humans are “hardwired” to connect with the natural world, and that being in nature had a profoundly positive effect on human health. Li’s research seems to corroborate this. For example, one of his studies looked at whether forest bathing could improve sleep patterns among middle-aged Tokyo office workers who tended to suffer sleep deficiency due to high levels of stress. During th...