As autumn paints the trees in vibrant colors, many are drawn to the forest not just for its beauty, but for the potential health benefits associated with spending time in nature. Known as "forest therapy" or "sylvotherapy," this practice claims to harness the healing powers of trees. But what does science say about the benefits of forests on human health?
For decades, researchers have studied various ecosystems, including forests, to uncover their potential positive impacts on health. Numerous studies indicate that spending time in nature, especially forests, can enhance overall well-being. Evidence suggests that forest exposure may reduce stress and anxiety, while also improving immune function, concentration, and mood.
In Europe, the COST (European Cooperation in Science and Technology) initiative, funded by the European Union, launched the "Forests, Trees, Human Health and Well-being" project in 2004. Over four years, 160 scientists from 24 European countries, along with participants from Asia, Australia, Canada, and the United States, worked to deepen the understanding of how forests and green spaces benefit health.
The findings are mixed:
On one hand, research seems to validate the health benefits of forest outings, linked to sunlight exposure (and thus Vitamin D) and the physical activity involved, along with the stress-regulating properties of plants.
On the other hand, there is currently no solid evidence proving that forest exposure directly improves immune function, motor skills, or learning.
The concept of "shinrin-yoku" or "forest bathing" was formalized in the 1980s by Japan's Ministry of Agriculture, Forestry and Fisheries. In response to health issues arising from urban living, the Japanese government viewed this practice as a novel public health preventive measure. Since then, it has evolved into what is now recognized as "forest medicine" or sylvotherapy.
Dr. Qing Li, a Japanese physician and researcher, has been instrumental in popularizing this concept globally. An associate professor at Nippon Medical School in Tokyo, his research focuses on the biological effects of "phytoncides," volatile compounds emitted by trees, and how time spent in forests may promote better health.
Dr. Li's approach is based on a theory: immersing oneself in a forest and engaging the five senses—listening to the wind rustling through leaves, breathing in woody scents, and touching trees—through a series of exercises could enhance physical and mental health. Japan has designated numerous "therapeutic forests" and shinrin-yoku trails, where trained practitioners guide visitors through sensory experiences, combining walks with relaxation, meditation, and sophrology sessions.
Despite the growing enthusiasm for sylvotherapy, especially in Europe, it is not yet recognized as a formal medical practice. The scientific community believes it has not sufficiently demonstrated its efficacy.
Researchers involved in the COST initiative acknowledge that "nature-based therapeutic interventions seem to be effective in certain contexts," particularly for depression, anxiety, schizophrenia, bipolar disorder, post-traumatic stress disorder, and attention deficit hyperactivity disorder (ADHD). However, they note that studies validating these outcomes are often criticized for their lack of quality. Few studies are well-rated, and many have faced exclusion from scientific publications due to insufficient rigor.
Currently, the purported benefits of forest bathing have only been measured over short periods, often with too small groups to yield relevant statistics, or without accounting for external factors that may influence results.
As it stands, sylvotherapy struggles to establish standardized therapeutic protocols that would allow for the measurement of its effectiveness, and thus cannot be recognized as an official medical practice.
Moreover, like many alternative therapies, sylvotherapy can be practiced without any specific qualifications or certifications. Beyond the commercial interests of some practitioners, who may charge exorbitant fees for "therapeutic" forest walks, there is a risk of exploitation, particularly targeting vulnerable individuals seeking solutions for physical or mental distress.