You don't need a guide to teach you how to practice the calming, restorative art of Shinrin Yoku, otherwise known as forest bathing. All you need is a forest to bathe in and this book. 

People used to live closer to nature. Writers have for hundreds of years extolled the benefits being immersed in the beauty of the natural world. We extol the cowboy on his rolling hills, the woodsman beneath his leafy canopy, and the fly fisherman lazily casting flies from midstream. But now more than ever, we isolate ourselves from the very environment which produced us, and it is taking its toll. In the early 1980s, Shinrin Yoku or "Forest Air Bathing" sent nature-starved city dwellers into the forests of Japan laden with devices to monitor their heart rate and brain waves. The results were positive. 
Over the years, the technology has gotten smarter and the pool of data has grown into an ocean of the evidence we should have known intuitively: Being outside is good for you. Since then, a cottage industry has sprung up around nature therapy. People are spending thousands of dollars to become certified in the art of instructing their "students" to lay underneath trees and look up at the sky. And their students are paying hundreds of dollars to lay beneath those trees. I could have signed up for and taken these classes, printed business cards, and frisked you for money to go with me into the forest, and I bet I would have been excellent at it. I'm so adept at walking on trails and laying beneath trees, they once sewed an Eagle Scout badge on my BSA uniform.