Deep roots: Realising the public health benefits of exposure to forest environments

Forests today constitute nearly one third of land cover worldwide, sequester nearly a third of carbon dioxide, and promote, maintain and restore health and wellbeing. Recent research has begun to unravel the therapeutic effects of forest environments. Reported benefits of forest therapy include mental health, cognitive function, the immune system, glycaemic control, pain relief, and hypertension. There is some evidence that biogenic volatile organic compounds emanating from trees themselves, so-called phytoncides, may also exert an antihypertensive effect. Decreases in objective measures of anxiety and depression have been attributed to forest environment exposure, with significantly lower scores on the profile and mood state questionnaire in the negative subscales of tension-anxiety, depression, anger-hostility, fatigue, and confusion. Limitations in the evidence base include small sample sizes, lack of research into long-term health effects, inconsistency around dose reproducibility and forest/woodland typology. The benefits to public health from investment in more detailed research could be a cost-effective strategy to mitigate the expensive burden of cardiovascular disease and mental illness on society, particularly in the wake of the ongoing COVID-19 pandemic. Isolating the elements of the forest-bathing experience responsible for its health benefits is difficult, although some evidence suggests that it may be a composite product of pleasant green scenery, soil, fresh air, sunlight, clean water, sounds of streams and waterfalls, bird song and the natural aromas of trees, plants, and flowers. The concept of green prescriptions is still in its infancy. With a greater awareness of the health benefits of forest immersion, the future medical consultation is likely to incorporate specific questions on this aspect of a patient’s lifestyle. There may be a role for forest therapists who can counsel patients about the optimal intensity and duration of forest exposure for their individual health needs.