Effects of Forest Therapy on Children in Socially Disadvantaged Families: A Systematic Review

Purpose:  Children in socially disadvantaged families and welfare facilities have higher level of aggressiveness, socio-psychological problems such as depression, shrinkage, low self-esteem and social maladaptation than other children. Forest therapy refers to a visit to forest areas or various activities which take place in forest areas for relaxation, healing, and wellness. In spite of the increasing attention to the various health benefits of forest therapy, until now, systematic review on the body of evidence for the effect of forest therapy on vulnerable children has not been conducted. A clearer and comprehensive understanding of the effects of forest therapy on vulnerable children is needed for further refinements of forest therapy programs. The purpose of this study is to systematically review the forest therapy programs designed for vulnerable children to identify contents, format, and strategies essential for effective forest therapy programs.

Methods:  This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Various databases including PubMed, EMBASE, CINAHL, KISS, RISS, and DBpia were used to identify relevant studies published up to September 2016. The two authors independently screened the full text articles using the following criteria: 1) intervention studies assessing the effects of forest therapy among vulnerable children ages 8 and 13; 2) unpublished thesis; and 3) articles or thesis written in English or Korean. The Methodological Index for Non-Randomized Studies (MINORS) measurement tool was used to assess the risk of bias in each trial.

Results: A total of 4,813 records, including 3,915 records published in English and 898 records published in Korean, were retrieved from initial database searches. Finally, 8 articles in total (English: 0, Korean: 8) were included in the present systematic review. The most common research design was quasi-experimental pre-test and post-test study. None of the studies used randomized controlled trial (RCT) and the sample size ranged from 16 to 308. Walking, observation in the forest and playing with natural objects were the key components of the forest therapy. The length of time over which the interventions were undertaken ranged from 1 day to 15weeks. Only one study had a 4-week follow-up. The most common variable was sociability among those of forest therapy effects and the next was psychological health-related variables such as depression, anxiety, and stress level. Most of studies used self-reported questionnaires and only one study used both self-reported questionnaires and physiological measures. Regarding the quality assessment based on the MINORS criteria, 7 studies were rated 17.7 (out of 24) and 1 study without control groups was rated 8 (out of 16). Regardless of the diversity in format and contents of forest therapies, most of studies showed significant positive effects on vulnerable children.

Conclusion:  This systematic review showed that forest therapy is one of the emerging and effective intervention approaches to improve sociability and psychological health among vulnerable children. Limitations on the current programs identified from the review were as follows; 1) small sample size; 2) inadequate information about research process. Future studies assessing the long-term effects of forest therapy on vulnerable children using rigorous study designs are needed.