This study conducted a systematic literature review and meta-analysis on academic papers that studied the stress improvement effects of forest therapy, to calculate the overall average effect size and the impact on the heterogeneity of the effect size...
This study conducted a systematic literature review and meta-analysis on academic papers that studied the stress improvement effects of forest therapy, to calculate the overall average effect size and the impact on the heterogeneity of the effect size for each sub-controlling variable, was reviewed. On the basis of this study, we aim to verify and generalize the stress-improving effects of forest therapy and provide scientific evidence to be recognized as an effective intervention method for stress prevention and management.
A thesis for the degree of Master in February 2024.
As a result of searching domestic and foreign related academic papers and systematically reviewing, the 40 papers finally selected. It was found that research has been conducted steadily since 2010 and that studies on youth and adulthood who are expected to be most exposed to stress due to social life, etc.. In addition, looking at the test locations, the study revealed that there are more urban forests than natural forests, so the demand for forest activities and forest healing programs at urban parks close to residences is expected to increase further. In terms of intervention settings, it was analyzed that the majority of studies were conducted on semi-healthy people or the general public rather than patients. Although stress is a symptom that can commonly occur in the general public without a specific disease, the resulting health issues are quite significant. This indicates that managing stress effectively is very important to everyone.
Next, looking at the meta-analysis results, the overall average effect size was -0.9023, indicating a large effect size based on Cohen's interpretation standards, which is in line with the effect size of stress reduction through other intervention methods(reading therapy, music therapy, counseling therapy, etc.). The effect size was relatively large. Subsequently, due to heterogeneity between studies, analysis was conducted by lower-level control variables such as study characteristics(subjects, intervention settings, etc.) and forest healing program characteristics. In terms of research design, NRCTs(SMD=-0.9740) were larger than RCTs, and by life cycle, the school-age and adolescent group(SMD=-1.4859) was followed by the infant/toddler group(SMD = -0.9759). The healthy general population(SMD=-0.9330) showed a larger effect size than the patients, and the session type had a larger effect size than the lodging type, with the largest effect size occurring in sessions 31∼40(SMD=-1.2792). The comparison between the effect sizes in natural and urban forests(SMD = -1.0016) revealed no substantial difference. However, a noteworthy contrast was observed when comparing structured and unstructured forest therapy programs. The study found that unstructured programs(encompassing activities like hiking, walking, and viewing scenery, etc) exhibited a more pronounced effect size(SMD = -1.4595) in comparison to their structured counterparts. This research primarily included experimental studies where unstructured forest therapy was implemented in a session-based type, whereas structured programs were a mix of lodging and session-based approaches, possibly leading to the observed variance in effect sizes. Additionally, it was analyzed that unstructured forest therapy programs demonstrated a greater effect size in natural forests, while structured forest therapy programs showed a larger effect size in urban forests. These findings imply that for effective stress reduction, a two-phased approach might be beneficial: initially engaging participants in unstructured forest therapy activities within natural forests to moderately reduce stress levels, followed by more organized, structured forest therapy programs in urban forests proximate to their living areas. This approach could yield enhanced outcomes in stress alleviation.
Although there have been many systematic literature review and meta-analysis studies on forest therapy interventions, this study is the first achievement to draw generalized conclusions by focusing on specific benefits such as stress improvement effects. In order to get the effect of reducing stress, simple forest activities in a nearby urban forest can be of great help. If research to synthesize, analyze, and generalize these individual studies is actively conducted further, it is expected that it will help to establish the scientific basis for the various benefits provided by forests.
Key words : Forest Therapy, Forest, Forest Activities, Stress, Effect,
Systematic Literature Review, Meta-Analysis