Important to note: The underlying meta analysis included interventional studies and might reflect a real causal link: """We included 103 observational and 40 i

Important to note: The underlying meta analysis included interventional studies and might reflect a real causal link: """We included 103 observational and 40 interventional studies investigating ~100 health outcomes.""" Later in the paper the authors say that the interventional studies were mainly about forest bathing in Japan, where the control group did equivalent activities in an urban setting: """Within the 143 studies, 40 were interventional and the remainder observational. Out of the 40 interventional studies, 27 were investigating the association between shinrin-yoku and various health outcomes. Shinrin yoku, or “forest bathing” is a popular practice in Japan and neighbouring countries, and is defined as “taking in the atmosphere of the forest” (Park et al., 2010). It is said to have health-promoting properties and to reduce stress (Park et al., 2010). Participants of shinrin-yoku spend time in the forest either sitting or lying down, or walking through the forest. In studies investigating forest bathing, a control group carried out the same activity in an urban environment. These studies typically had small numbers of participants (between 9 and 280 participants).""" So there is some small reason to believe that there might be a real, exploitable link here.