April 23, 2022
I have a 0.6 ounce, black, smooth, water-polished stone I found in Frogtown Creek beside the trail leading to the Upper DeSoto Fall in north Georgia. I soon discovered that, due to its weight and shape, it was not only pleasing to touch and hold, but because my thumb fits exactly on its flat side, it makes a great worry stone. At least, that’s what many people would call it, although comfort stone or fidget stone seems more suited to the way I use it. I do with the stone what Native Americans and others have always done with their worry stones: I rub it between my thumb and forefingers, turn it over and over repeatedly, and generally enjoy the feel and weight of it in my hand. Although I didn’t start carrying my stone in order to address anxiety or stress, I’m sure that the tactile experience of holding and rubbing it, combined with happy memories, does have a calming and salutary effect.
Lush with deciduous and evergreen trees, including eastern hemlock and some enormous old-growth pines as well as rhododendron, the trail where I found my worry stone has a cool Tolkienesque feel—especially beautiful because of the nearby stream and waterfalls. It’s a great place to immerse yourself in the atmosphere of the forest—an activity the Japanese call shinrin-yoku or, in English, forest bathing. The practice was developed in the 1980s and became an important part of preventative healthcare and healing in Japanese medicine. Since then, numerous scientific studies have established that a walk in the forest offers reliable boosts in your physical and mental health.
In the late 1800s, German and American physicians established sanitoriums for tuberculosis patients in the pine forests of Germany and the Adirondack forests of New York. All the physicians reported that patients improved from exposure to the forest air. They speculated that pine trees release a healing balm into the air, which as it turns out was a pretty good guess.
Although the sights and sounds of a forest have a calming effect, the nineteenth century TB physicians got it right when they thought the forest air was the key factor. Forests contain chemical and biological agents with verified health benefits. When we inhale forest air, we benefit from at least 2 inhaled agents: phytoncides and beneficial bacteria. If there are flowing streams or waterfalls in the forest, we get a bonus benefit: negatively charged air ions.
Phytoncides are volatile organic compounds (VOCs) released by trees to protect themselves from bacteria, insects and fungi. The VOCs emitted by conifers such as the eastern hemlock and pine are particularly pungent, making a hot summer day hike on the DeSoto Falls Trail an intense outdoor aromatherapy session. The forest scent derives primarily from the common aromatic VOCs limonene and pinene.
Pine trees are some of the most prolific producers of limonene, which is also abundant in the peels of lemons, oranges and other citrus fruit. Known for its ability to elevate mood and reduce anxiety and stress, limonene also acts as an antioxidant in your body and may thereby reduce your risk of certain cancers. Several studies suggest that limonene may be good for your heart and coronary health by lowering blood pressure and reducing both triglycerides and LDL cholesterol.
The phytoncide pinene smells like cedarwood, pine trees, and Christmas trees. Besides in conifers, it is found in orange peels, turpentine, rosemary, dill, basil, and parsley. It has strong anti-bacterial and anti-inflammatory effects, so protects your lungs against some infections. Its antibiotic powers are so powerful that the air in a forest of young pine trees is virtually germ-free. Pinene also dilates the bronchial tubes in your lungs—maybe one reason it sometimes seems easier to breath more deeply in the forest. Phytoncides also decrease your levels of the stress hormone cortisol.
It is a well-established fact that forest bathing will improve your mood and sense of well- being. The aromatherapy provided by phytoncides would probably be enough to yield this result. However, Mycobacterium vaccae, a common microbe in soil, also has a mood-boosting powers. The bacterium has no adverse health effects and acts as a natural antidepressant by causing neurons to make serotonin.
The forest air around DeSoto Falls has yet another mood-boosting factor: negative air ions (NAIs). NAIs are found under waterfalls and near seashores. They are generated by the Lenard Effect discovered by Philipp Lenard who won the Nobel Prize of physics in 1905 for his research on cathode rays. The Lenard Effect says that NAIs are generated when surrounding air molecules charge themselves negatively because water droplets collide with each other or collide with a wet solid to form a fine spray of drops. Studies have shown that hours of exposure to NAIs can elevate your mood and reduce anxiety and stress.
Neurological biochemistry and negative ions aside, there’s another very familiar reason why a walk in the forest boosts your mood: the experience of beauty combined with an awareness that you are intimately connected to and surrounded by an enormously complex, astonishing population of other living things. If I were entirely blind and deaf, you could still lead me along the trail to the observation deck before the DeSoto High Falls, and the phytoncides and negative ions I would breathe could also be duplicated in the air of my living room. In both cases, we can assume that my mood would be boosted—but hardly in the same way or to the same degree as it is on my trail walk which is a continual feast of sights and sounds, of changing colors, sunlight, and shadows beneath towering firs and hardwoods, of the babbling of the nearby creek, of the chirping, singing, and flitting of songbirds in the canopy overhead as patches of blue sky come in and out of view, and of the unexpected appearance of an airborne wasp or a trail-crossing tiger beetle. Goethe’s “Wie herrlich leuchtet mir die Natur” comes to mind: “How glorious Nature shines for me.”
Johann Wolfgang von Goethe
https://www.fs.usda.gov/inside-fs/out-and-about/walk-woods-wellness-health-benefits-forests
https://www.health.harvard.edu/blog/can-forest-therapy-enhance-health-and-well-being-2020052919948
https://www.sciencedaily.com/releases/2019/05/190529094003.htm