Forest Therapy

Current estimates in Australia indicate the escalating costs of poor mental health are approaching $70 Billion annually, with the cost of disability and premature death due to mental health, suicide and self-inflicted injury equivalent to a further $151 Billion (Australian Government Productivity Commission, 2020). Despite the effectiveness of psychotherapy across different mental health conditions, there remains variation in the success of these treatments based on patient characteristics, clinician factors and context factors (Hunsley et al., 2014; American Psychological Association [APA], 2013). This is particularly apparent for clients that present with a history of complex ongoing interpersonal trauma, who typically have difficulties engaging in talk-based therapies (Kezelman & Stavropolous, 2019). As such, interest has grown in alternative and complementary therapies that might address some of the factors that lead to poorer outcomes for this client group, with a recent attention on the psychological benefits of nature-based interventions (Timko Olson et al., 2020; Corazon et al., 2019).

There exists an established and growing body of evidence about the physical health benefits of contact with nature (Wen et al., 2019; Bowler, Buyung-Ali et al., 2010; Townsend & Weerasuriya, 2010), with an evolving evidence base for the mental health benefits of exposure to nature (Corazon et al., 2019; Roberts et al., 2019; Capaldi et al., 2014). For example, there is now some evidence to suggest that exposure to urban environments is linked to an increased incidence of mental health concerns (Van Den Bosch & Meyer-Lindenberg, 2019). On the contrary, evidence suggests that exposure to the natural environment is associated with a reduction of psychological distress. With half the world's population living in urban areas and the World Health Organisation (1996) considering stress a major health risk in modern urban life, the therapeutic potential of spending time in nature provides a promising, cost-effective approach to addressing the escalating costs of poor mental health.

            Nature-based interventions are often explored through the lens of ‘Ecopsychology’, which is defined as a way of exploring the relationship between, personal health and wellbeing, and the health of our planet (Roszak et al., 1995). This holistic perspective aims to help individuals move away from an ‘ego-self’ that is separate from nature, towards an ‘eco-self’ that is an interconnected and interrelated part of nature, which typically occurs through mindful attention to the natural world (Danon, 2019; Roszak et al., 1995). Mindfulness is often defined as “moment-to-moment awareness, cultivated by paying attention in a specific way, in the present moment, as non-reactively, non-judgementally, and open-heartedly as possible” (Kabat-Zinn, 2011). Mindful, nature-based therapies are varied and include mindful walking in forests (Yang & Conroy, 2019; Kim et al., 2009), mindful interventions in a nature context (Willert et al., 2014), Forest Bathing (Shinrin-yoku) (Hansen et al., 2017), and Forest Therapy (Lee et al., 2017). Forest Therapy, the focus of this research, involves mindfully taking in the atmosphere of the forest through the senses and developing an emotional connection to the forest (Miyazaki & Motohashi, 1995), following a manualised and replicable protocol (Kotte et al., 2019).

In light of the evidence base supporting the relationship between nature and human health, research into the development and application of specific mindful nature-based interventions is emerging. A systematic review into the effects of Forest Therapy on depressive symptoms in adults by Lee et al. (2017) found that it was associated with decreases in depressive symptomology across 28 studies that included at least one control group, across highly heterogenous populations and treatment conditions in mostly Asian countries. Moreover, in a systematic review of the medical empirical research of forest bathing by Wen et al. (2019), the mood states of depression, tension-anxiety, fatigue, confusion and anger-hostility were found to be amenable to change and significantly decreased across the majority of studies, which mostly looked at healthy participants in Asian countries. A further six exploratory studies noted a significant decrease in levels of anxiety and three exploratory studies reported a significant decrease in reported levels of depression (Wen et al., 2019). Furthermore, a systematic review and meta-analysis of nature-based mindfulness, including Forest Therapy, by Djernis et al. (2019) exploring 25 studies with a combined total of 2990 participants in Northern America, Asia and Europe found that across highly diverse intervention methods, that measures of positive psychological effects pre and post the interventions were statistically significant and of a medium effect size, with mindfulness practiced in nature found to be moderately superior to mindfulness practiced in non-natural settings (Djernis et al., 2019). Overall, these reviews suggest that mindful nature-based interventions are a promising complementary approach for mental health. Nevertheless, given considerable heterogeneity between participant characteristics, intervention protocols and the cultural context in which the research takes place, further research is indicated.   

Despite the promising evidence for the positive effects of mindful nature-based interventions for mental health, studies examining the impact of these interventions with clinical populations are limited. These studies include Kim et al. (2009) who conducted a study on a population in South Korea with clinical depression, comparing the efficacy of four three-hour sessions of cognitive behavioural therapy (CBT) in a forest environment, CBT in a hospital setting, and an outpatient control group. The forest group had a remission rate of 61% compared to 21% in the hospital group and 5% in the control group. These authors concluded that the forest provided a rich environment to engage the senses and more easily facilitated meditation, reflection and other behavioural practices integral to CBT. Furthermore, a sample of 20 participants in America, diagnosed with Major Depressive Disorder (MDD) were found to have cognitive and affective benefits from interacting with nature during two 50 minute walks in an arboretum compared to a walk in an urban environment, with some effect sizes being five times greater than those observed in previous studies involving healthy adults (Berman et al., 2012). Shin et al. (2012) examined the effects of a nine day forest camp in South Korea, on 92 participants (47 treatment and 45 control) with a moderate level of depression associated with alcohol use disorder. The intervention included meditation, exercise and counselling in a nature setting and found that depression levels improved to a level that indicated no depression compared to the control group, which maintained a moderate level. Similarly, a decrease in anxiety and an improvement in mood was found for a sample of 50 inpatients in a psychiatric treatment unit in Poland with affective and psychotic disorders. In this single group study, participants undertook a one off, one hour and 45 minute walk in a suburban forest environment (Bielinis et al., 2019). Additionally, a small sample of eight Danish war veterans with PTSD in a 10-week nature-based therapy program, spent three hours per day, for three days a week in a forest therapy garden. Participants reported an increase in feelings of calm and connectedness and a decrease in PTSD symptomology (Poulsen et al., 2017). While these studies indicate that the environmental context or ‘setting’ is an important factor in treatment efficacy, they have occurred across diverse cultural contexts with a lack of standardised approaches making it difficult to compare results and provide a strong consensus.

The growing empirical evidence for nature-based interventions is supported by a number of established theories that explore the effects of nature on human health and wellbeing. American biologist E.O. Wilson describes ‘biophilia’ as a biological need to love and connect with nature because we have evolved in it (Wilson, 1984). Kaplan and Kaplan’s (1989) Attention Restoration Theory (ART) proposes that time in nature allows us to restore involuntary attention, which in turn allows us to restore our voluntary attention – the type used in cognitively demanding tasks at work. Our innate love of nature is an appropriate setting for rest, and our ability to get away from the mentally congesting signals of urban life and immerse ourselves in nature can allow space for our mind to gain perspective. Similarly, stress-reduction theory states that human stress levels are reduced when in nature, as natural environments do not require large amounts of information processing due to humans having adapted and evolved in nature (Ulrich, 1983).

Despite the empirical and theoretical basis for utilising nature in a therapeutic context as noted above, the development of this research domain has been hampered by methodological limitations. What constitutes mindful nature-based interventions is wide ranging, with terms often used interchangeably (e.g., Forest Therapy, Forest Bathing and Nature Therapy). Additionally, the methodological heterogeneity of the interventions and participant characteristics make generalising the results difficult (Corazon et al., 2019; Djernis et al., 2019; Lee et al., 2017; Hansen et al., 2017). Furthermore, underreporting of intervention compliance (Wen et al., 2019), a lack of research exploring clinical populations (Lee et al., 2017), the need for a combination of quantitative and qualitative research (Hansen et al., 2017), and a call for more rigorous and transparent methodologies (Corazon et al., 2019) has been noted. 

Over the last decade there has also been increasing interest in how alternative therapies might augment or complement existing mental health treatments (Capon et al., 2021; Van der Kolk et al., 2014; Fjorback et al., 2011). This is reflected through the successful incorporation of other mindfulness-based approaches with existing treatments. For example, a meta-analysis and systematic review from Fjorback et al. (2011) has found medium effect sizes for Mindfulness Based Stress Reduction (MBSR) and Mindfulness Based Cognitive Therapy (MBCT) for reducing the likelihood of depressive relapse, where both therapies incorporate mindful practice with current psychological tools including CBT. There are also a small number of studies that have incorporated yoga with psychological treatments with positive results (Capon et al., 2021; Van der Kolk et al., 2014). Given the commonality between yoga as a mindful movement practice and nature-based therapies, specifically Forest Therapy, the integration of a mindful nature-based treatment with psychological treatment seems a particularly promising line of research.

In summary, despite the significant promise of mindful nature-based interventions, there are limited studies, generally with methodological weaknesses, that explore this intervention with clinical populations and no studies to date have been found that investigate this as an adjunct to psychological treatment. As such, this present research aims to explore the acceptability and feasibility of Forest Therapy as an adjunctive intervention. This includes utilising a standardized Forest Therapy protocol, which is based on the International Core Curriculum of Forest Therapy (ICCFT; designed, evaluated and validated by over 120 experts from 20 countries; see Kotte, et al., 2019) and conducted by an INFTA-Certified and Accredited Forest Therapy Guide (INFTA – International Nature and Forest Therapy Alliance, Melbourne/Australia & Hamburg/Germany). A manualised, process-driven intervention is essential for the integrity and replicability of this research. Exploring the acceptability and feasibility of this study is a recommended first phase prior to a large-scale Randomised Control Trial (RCT), due to the complex nature of the intervention and it occurring in a new environmental setting (Arain et al., 2010; Bowen et. al., 2009). This study is part of a larger mixed-methods study that was conducted at a community counselling service in regional Australia, which provides evidence-based psychological treatments for a wide range of mental health conditions. This study seeks to understand within this clinical context whether Forest Therapy is: 1) an acceptable complementary intervention, and 2) a feasible complementary intervention. If Forest Therapy is found to have clinical utility, then Forest Therapy may be utilised to address the significant mental health challenges in Australia and help to support other existing treatment modalities