There are nearly two dozen certified trails around the world that guide visitors to engage with nature in ways that benefit their health and foster deeper exploration. A walk in the woods is not only good for you physically, however, it is also good for you psychologically. Studies show time spent in nature reduces mental fatigue and irritability, cortisol levels, and stress. Nature is important for our health in so many ways, says Melissa Lem, a Vancouver doctor and director of a Canadian program encouraging doctors to prescribe time in nature for their patients. There is a standardized recommendation that patients spend at least two hours in nature each week and at least twenty minutes each time. No wonder many cities and parks are installing forest therapy trails  short, self-guided paths ment to immerse users in nature and engage all their senses. Designed by organizations such as the Association of Nature and Forest Therapy and Global Institute of Forest Therapy and Nature Connection, more than a dozen trails have launched in the United States, Costa Rica, Slovenia, and Canada. Inspired by shinrin-yoku, the Japanese tradition of so called forest bathing, forest therapy trails are typically a mile or so long with little change in elevation, access to water, and a diversity of plants, including coniferous trees. Most are on unpaved dirt paths, an immediate visual and tactile clue that you are not in an urban environment. The main thing is that the trail should provide a relaxing experience. The soundscape is also very important, so next to freeways is not ideal. Certified trails have prompts  signs, brochures, or apps  that guide visitors to inhale deeply, listen to water, touch a tree, or even close their eyes. Typically, in these spaces, people walk briskly as exercise or to identify things like birds, and their other senses often shut down. By closing your eyes, you enable the other senses to kick in. The trail guides also give users information about the surrounding environment and its effects on the body and mind. For instance, in Rouge Valley Park in Markham, Ontario, signs point out that pine trees emit phytoncides, essential oils which can have a calming effect, and that some evergreen needles  such as spruce, eastern hemlock, balsam, and pine  can be made into a tea rich in vitamin C. Last year, Pinnacle Park opened its forest therapy trail. Signs cue users to close their eyes and listen for rhythms in the nearby and distant sounds, to explore the scents around them, and to watch a leaf placed on a stream drift away. 
