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Forest Therapy Trails: A Conceptual Framework and Scoping Review of Research

Northern Research Station, USDA Forest Service, 1033 University Pl. Ste. 360, Evanston, IL 60201, USA
Health & Technology Partners LLC, Milwaukee, WI 53202, USA
Pacific Northwest Research Station, USDA Forest Service, Juneau, AK 99801, USA
Greenspaces for DC, 1102 Monroe Street, NW, Washington, DC 20010, USA
Author to whom correspondence should be addressed.
Forests 2022, 13(10), 1613;
Received: 2 September 2022 / Revised: 27 September 2022 / Accepted: 30 September 2022 / Published: 2 October 2022
(This article belongs to the Section Urban Forestry)


While most definitions of forest therapy emphasize the role of multisensory, immersive experiences in nature to achieve human health and wellbeing outcomes, reviews of research on forest therapy to date have predominantly focused on outcomes and provide limited insight on the factors and conditions that give rise to nature experiences. In this scoping review we employ a conceptual framework developed in the context of landscape perception research to examine empirical studies of forest therapy in terms of how the fuller process of human, forest, interaction, and outcome components are conceptualized and measured. Our literature search identified 266 studies focused on forest therapy and related activities, which were coded on a number of variables related to each of the four components in our framework. While most studies reported positive mental and/or physiological health outcomes using a wide array of measures, the typical study used small, homogeneous samples of participants who engaged in limited interactions with a forest environment that was minimally described. However, our analysis also identified a wider range of findings with regard to human-forest interactions, which together provide important insights for guiding forest therapy research and the provision of forest therapy trails, settings, and programs.

1. Introduction

Forest therapy is an umbrella term used in this paper to encompass activities by individuals and groups in the mindful engagement of slow, multi-sensory, immersive experiences in forests and other natural and semi-natural environments to achieve mental and physical health along with other wellbeing outcomes [1,2,3]. Related terms include forest bathing (shinrin yoku), nature therapy, forest walks, and forest healing. Although forest therapy engagements can take place while stationary in a confined location, in non-forested settings such as designed gardens and urban greenspaces, or even remotely through a window or digitally, most engagements take place in the form of walks along a path within a forest to optimally experience the array of sights, sounds, smells, and other sensory phenomena afforded along the route [3,4]. This interaction between person and landscape, individually or mediated by a trained forest therapy guide and shared among a group of participants, has been linked to a range of positive health benefits, from psychological stress relief and improvements in mood to physiological improvements in blood pressure and increased immune response [5]. On a broader level, forest therapy as a practice can bring a fuller awareness and appreciation of our umwelt, the world as we perceptually experience it, and lead to a better understanding of what it is to be human and connected to other living things in the natural world [6].
Because of these and other promising outcomes, forest therapy is viewed by an increasing number of health professionals as an alternative or complementary treatment for individuals with an array of health issues and an enjoyable wellness practice for everyone [7,8]. From the initial formalization of shinrin yoku as a health-based activity in Japan in the early 1980s [9], a rapidly growing body of evidence-based research has motivated health professionals in many countries to develop forest and nature-based therapy programs, including advocacy initiatives for doctors to prescribe a “dose of nature” to their patients [10,11]. However, while forestry agencies in a few countries such as Japan and South Korea have responded to this demand by developing networks of forest therapy bases and trails [12,13], in most places the selection of settings is left to the individual or forest therapy guide, without clear criteria for what features or conditions help facilitate desired health and wellness outcomes.
For these reasons, we established the Forest Therapy Trails project to examine the literature and conduct original research with the goal of developing guidelines for trail design, planning, and management [14]. In this initial effort, we review the forest therapy research literature to better understand the nature of people-forest interactions that give rise to health and wellbeing outcomes. With a few notable exceptions [15,16,17], most reviews of research on forest therapy and related concepts to date have focused principally on health outcomes. On one hand this is unsurprising, for many reviews adhere to standardized guidelines and procedures developed for medical research, which emphasize outcome effect measures (e.g., direction, magnitude, heterogeneity) and data quality (confidence, biases) [18,19,20,21,22,23]. On the other hand, however, the medical science orientation of many research reviews and the individual studies they select for inclusion often pay little attention to broader study details such as the nature of the forest setting in which health interventions take place or how participants interact with those settings in order to realize beneficial health outcomes [24]. Paradoxically, despite the focus of forest therapy on forests as a source of health outcomes, relatively little summary evidence has been brought to light about the multisensory, immersive experiences that underlie forest therapy engagements.

A Conceptual Framework for Understanding Forest Therapy Engagements

In this scoping review [25] we depart from the health outcomes paradigm to examine forest therapy research in terms of the fuller process of how human, environment, interaction, and outcome components are conceptualized and measured. To guide our work, our review builds upon a conceptual framework developed by Zube et al. [26] for the analysis of research in landscape perception, a multi-disciplinary field of inquiry concerned with understanding and assessing human responses to large-scale physical environments. While similar, more recent frameworks have been proposed, e.g., [27], the Zube et al. [26] framework is well-grounded in theory [28,29], enjoys continued use and citation [30,31], and is conceptually clear for guiding a review of research.
The framework, which we have adapted here to the specific context of research on forest therapy (Figure 1), views human health and wellbeing as outcomes that result from the interactions between humans and the forest environment. Although forest therapy engagements can be quite varied, they can be usefully examined in terms of each of the four human, forest, interaction, and outcome components in the framework. For the human component, we were interested in who is being studied and how the study samples reflect the broader population that might participate in or could benefit from forest therapy. We were also interested in whether particular individuals or groups varied in their experiences or outcomes from forest therapy engagements [32,33]. For the forest component, our primary interest was in identifying important features and qualities of the forest environment that give rise to, or are thought to give rise to, therapeutic forest experiences. As with the human component, we also wanted to know if particular forest types or features were more or less effective at producing beneficial outcomes [34,35]. For the interaction component, we sought information on the structural nature of forest therapy engagements in terms of what types of activities participants engaged in and the duration of engagements. Additionally, important to us was the social nature of interactions, including the size of groups that participated in an engagement and whether and how guided forest therapy engagements differed from unguided ones [36,37]. Additionally, for the outcome component, similar to more standard reviews of the forest therapy literature, we wanted to identify the types of outcome measures being studied and the success of forest therapy engagements in achieving desired psychological, physiological, and other health and wellbeing outcomes [20,21,22].
In line with the purposes of scoping reviews [25], in the following sections we apply this conceptual framework to a set of research articles from a broadly defined search of the literature to identify key concepts and themes as well as patterns of central tendency and variability among a range of key variables. While we acknowledge that published research on forest therapy may describe a more limited subset of factors and conditions than might occur in actual forest therapy engagements, identification of what is being researched and reported can be a useful first step in understanding the current state of knowledge and future research needs, leading to improved settings and programs.

2. Materials and Methods

2.1. Article Search and Screening Procedures

To help identify an appropriate set of search terms, we examined previous reviews of the forest therapy literature [15,16,38,39,40]. With our project emphasis on forest therapy trails, we were particularly interested in research that focused on forests and trails, but recognizing that forest therapy engagements can take on a wide range of settings and activities, we did not limit our search to these terms.
We conducted our search using the following search string: “forest therapy” OR “nature therapy” OR “forest bathing” OR “shinrin yoku” OR “forest medicine” OR “nature-assisted therapy” OR “nature-based therapy” OR “park therapy” OR “forest walks” OR “forest walking” OR “nature walks” OR “nature walking” OR “healing forest”. A 9 March 2022 search in Scopus identified 512 articles. Using this same search string, the Scopus search identified 19% more articles than Web of Science, while a Dimensions search identified 30% more articles than Scopus and 54% more than Web of Science. Because Scopus provided a more robust selection than Web of Science and because we lacked institutional access to the analytical version of Dimensions, we used Scopus to build our database of articles.
From the downloaded .csv file of article information, we first screened the set to identify empirical research articles, eliminating full books and book reviews (n = 7); conceptual, editorial, and perspective essays (n = 66); errata (n = 1); and review papers (n = 79). From the remaining set of empirical articles (n = 359), we deleted duplicate listings (n =13) and reviewed the abstracts to eliminate those that were off-topic (n = 46). This left us with a targeted set of 300 articles, 25 of which were not retrievable via download or by contacting the corresponding author and another 9 that were not in English and not translatable, for a final sample of 266 articles for coding and analysis.

2.2. Concept Coding and Analysis

Except for one analysis described below where we employed a text mining approach, our coding procedures used the article as the unit of analysis (n = 266). To help characterize the article sample, we coded basic study information including date of publication, country location where the study focused, author disciplinary affiliations, and the type of research design and forest therapy research activity (e.g., forest bathing, forest therapy program) identified by the authors.
Using our conceptual framework (Figure 1) to guide the analysis, we then coded available study information for each of its four components. For the outcome component, as previously mentioned, the aim of our work was not to repeat previous reviews that evaluate the significance of study effects or quality of the research. Rather, in addressing the outcomes component in our framework, we sought to identify the types of measures being used and how they might vary by the type of research design employed. We also broadly coded the extent to which significant positive outcomes of the intervention were reported in the study.
For the human component, we coded sample size, demographic information (average age, percent female (only a few studies included nonbinary gender categories)), target population(s) studied, and whether the study design included any between-subject comparisons. While coding for most of these variables was straightforward and taken directly from the article abstract or full text, information about studies’ target populations required some thematic categorization to a smaller number of logical groupings. In this case, and for similar variables for the other framework components below, grouping was done by the lead author with consultation and review by the project team (co-authors).
For the forest component, we coded landscape type, forest type, urban-rural study location, and whether the study took place at a designated forest therapy or bathing site. Because the characteristics of forest sites and settings were of primary interest to our Forest Therapy Trails project, we coded an array of summary and detailed information for this component. To help characterize quantitative site parameters, we coded articles for available information on trail length, site size, and number of sites included in the study. Studies that made within-forest comparisons were identified and grouped by the types of comparisons made. Forest setting descriptions were excerpted from each article and coded in two ways to try and extract the maximum amount of information about the features and qualities of the sites studied. The first was a by-article coding where each forest setting description was reviewed and coded for word count as an overall measure of descriptive richness and thematically coded for specific notable features that were mentioned [41,42]. The second employed a text-mining approach inspired by Grilli and Sacchelli’s [24] review of the forest therapy literature, where the text corpus of title-keyword-abstract information was subjected to lexicometric analysis to identify and spatially map thematic groupings of key study concepts. We attempted a similar concept mapping of forest setting descriptions using VOSviewer [43], but the resulting clusters did not yield a meaningful interpretation so we manually grouped key concepts as identified by a frequency analysis of terms [42]. Finally, we sought to identify if the study design made any between-site comparisons of forests with other site types or control conditions, or within-forest comparisons by forest type or other conditions, and whether such comparisons resulted in significant differences in the outcome effects that were being assessed.
For the interaction component, we coded the type(s) of activities, duration, and number of sessions that participants engaged in as part of the study. In addition to these structural dimensions of the interaction, we also coded the social dimensions of maximum group size of the engagement and whether it was guided or unguided. Because these social-structural aspects of human-forest interactions might vary by the type of program, we also cross-coded studies by the type of forest therapy research activity as it was talked about in the article and identified by our keyword search string.
Additionally, as previously mentioned, the aim of our scoping review was to identify key concepts and themes and to describe patterns of central tendency and variability among variables of the four components [25]. To address this aim, our analytical procedures relied mainly upon reporting frequency of themes and categories along with mean/median scores and related statistics for key quantitative variables. Crosstabulations were also employed to help understand relationships between key variables, particularly as they related to study outcomes.

3. Results

3.1. Study Sample Characteristics

Table A1 in Appendix A provides a listing of sample characteristics for each of the 266 articles included in our review. Representative examples of studies corresponding to particular study variables are cited in the text of this and other subsections below. In terms of research type, forest therapy research is heavily oriented toward experimental work (n = 199, 74.8%), with most studies of this type following a pre/post research design where indicators of participants’ health and wellbeing are assessed before and after engagement in a forest or other natural environment [44,45]. The other research types were much less represented in the sample and in some cases we grouped together a number of similar approaches. Qualitative studies (n = 34, 12.8%) included in-depth interviews, participant observation, and focus groups with forest therapy participants [46,47], interviews with forest therapy providers and other professionals [48,49], mixed-methods post-occupancy evaluations [50,51], and clinical case studies [52,53]. Survey research (n = 15, 5.6%) included both large-scale general population surveys [54] and targeted onsite intercept surveys of forest visitors engaged or interested in forest therapy experiences [55,56]. Research types used in less than 10 articles included expert assessments such as suitability analyses [57,58] and site inventories [59], image analysis of virtual landscape representations [60] and social media selfie posts [61], and epidemiological studies [62].
We also categorized articles by how authors described the main activity they studied under the umbrella term that we have been referring to in this paper as forest therapy. We identified three main research activity types and three lesser activity types. The three main activity types included forest-, nature-, or park therapy (n = 101, 41.0%), often with an emphasis on multi-activity programs made up of a series of sessions over time [34,63]; forest bathing or shinrin yoku (n = 76, 28.6%), which were more often operationalized by a single walking or stationary activity of limited duration [64,65]; and forest, nature, or park walks (n = 53, 19.9%), which were often described in similar ways to forest bathing but did not use that term [66,67]. The three lesser activity types were forest experiences (n = 5, 1.9%) which mainly derived from tourism research [68,69]; virtual-based studies (n = 17, 6.4%) or “digital shinrin yoku,” which emphasized the use of digital representations of nature as an alternative or proxy to actual forest experience, sometimes in response to nature access constraints caused by the COVID-19 pandemic [70,71]; and forest air studies (n = 6, 2.3%), where the focus was on immunity or other health and wellbeing properties of the physical forest environment studied in the context of forest therapy [72,73].
Given the geographic origin of shinrin yoku, it was not surprising to find Japan to be the earliest and foremost location of forest therapy research, with 72 articles (27.6% of the entire sample) dating back to 1998. Of the 31 countries listed as the locations of forest therapy research in our sample, Japan and five other countries accounted for two-thirds of published articles to date (Figure 2). As the Figure 2 shows, research in Japan has steadily increased over 2006–2021, while studies in South Korea (n = 43) and China (n = 29) have increased greatly in recent years. Europe as a whole has also seen a big increase in recent years, from only 1 between 2006–2013 to 15 in 2014–2017 and 37 in 2018–2021.
Experimental studies accounted for at least two-thirds of articles in each of these top six countries, and while small cells sizes make it difficult to establish statistical significance for two-way tables, there did appear to be a larger proportion of qualitative studies based in Denmark (n = 4, 33%) and the UK (n = 3, 27.3%), more image analysis work coming from China (n = 6, 20.7%), and more studies employing surveys from Japan (n = 9, 12.5%). Additionally, of potential significance, studies from Japan tended to more often be described as forest bathing/shinrin yoku (n = 38, 52.8%), studies from South Korea (n = 33, 76.7%) and Denmark (n = 11, 91.7%) more often used the term forest therapy, and studies from the US (n = 9, 100%) and UK (n = 5, 45.5%) tended to use forest or nature walks.
As for author disciplinary affiliations, the natural resource professions (forestry, landscape architecture, recreation-tourism) were represented in the largest number of articles (n = 159, 59.8%), followed by the fields of medicine and health (n = 121, 45.5%), the social sciences (n = 69, 25.9%), environmental science and STEM fields (n = 26, 9.8%) and the arts and humanities (n = 2, 0.8%). Slightly more than half of the papers (n = 142, 55.3%) were authored by individuals within a single one of these affiliation groups, while the remainder were comprised of two (n = 97, 37.7%) or more (n = 18, 7.0%) affiliation groups, most often representing both the natural resource and medical-health fields.
Finally, we attempted to discern whether author disciplinary affiliations were associated with the type of research approach used in studies, using the subsample of papers where authors all came from a single field (n = 142). As might be expected, if authors were all from within the medical-health sciences, a high proportion of studies (n = 34, 87.2%) used experimental designs. Experimental designs also dominated the other disciplinary fields, though authors from the social sciences tended to employ qualitative approaches more often (n = 9, 33.3%) and authors from the natural resource professions appeared to employ a wider diversity of research types including qualitative (n = 8, 12.3%), survey (n = 7, 10.8%), and expert assessments (n = 4, 6.2%).

3.2. Outcome Component

3.2.1. Outcome Measures Studied

A large majority of studies (n = 219, 85.5%) employed psychological measures to assess health and wellbeing outcomes from forest therapy engagements, while about half (n = 135, 50.8%) employed physiological measures (including physical and psychophysiological). About 40 percent of studies (n = 101, 39.5%) employed both types of measures, while the others used only psychological (n = 121, 47.3%) or physiological measures (n = 34, 13.3%). The average study that included psychological measures employed 2.7 different measures, while the average study that included physiological measures employed 2.4 different measures, though the number of measures used ranged considerably, from 1 to 27 different psychological measures to 1 to 13 different physiological measures.
We tallied 246 different psychological measures used to assess health and wellbeing outcomes. These ranged from single-item measures such as willingness to visit or revisit [57,74] and sets of single-items such as a landscape feature checklist [75] used to assess environmental preferences, to previously developed and validated multi-item scales designed to assess various psychological states. The five most commonly used psychological scales were the Profile of Mood States (POMS) (n = 75, 34.2%), the Positive and Negative Affect Schedule (PANAS) (n = 34, 15.5%), the State-Trait Anxiety Inventory (STAI) (n = 21, 9.6%), the Semantic Differential (SD) (n = 22, 10.0%), and the Restorative Outcome Scale (ROS) (n = 17, 7.8%).
While there was some overlap between higher-order concepts for which these and other psychological measures were designed and employed, in Table 1 we attempted to classify measures used in the studies into broader psychological categories. As the table indicates, the studies in our sample sought to assess a wide variety of concepts related to psychological health and wellbeing, from commonly used concepts such as mood-emotion [76,77] and depression-anxiety-stress [67,78] to less-common concepts such as nature connectedness [79,80], self-esteem [81,82], mindfulness [83,84], and environmental learning [85,86]. While some of the qualitative studies tapped into similar concepts through the use of unstructured and semi-structured techniques, they also uncovered unique outcomes including an understanding of the “lived experience” of forest therapy including activity preferences and favorite places [87], improvements in the “capacitative body” of knowledge, skills, and motor-sensory capabilities [88], and “embodied spirituality” in experiencing the immensity and interconnectedness of nature [89].
We also tallied 81 different physiological measures, most of which assessed one or more aspects of heart rate (heart rate variability, RR interval) (n = 63, 46.7%) and blood pressure (systolic/diastolic) (n = 48, 35.6%) and tied to broader health concepts of stress-arousal and relaxation [90,91] (Table 1). Less-often studied measures include indicators of immune response and inflammation such as natural killer (NK) cell activity and inflammatory cytokines [64,92], physical health and mobility measures such as the Brief Physical Activity Assessment and Neck Disability Index [93,94], and cognitive function such as EEG [95,96].

3.2.2. Outcome Effects

Finally, we attempted to summarize the effects of forest therapy engagements on health and wellbeing outcomes. With many studies employing multiple outcome measures and complex research designs this was not always easy to do, but using the study abstracts and discussion/conclusion summaries as guidance to how authors characterized their principal findings, we grouped effects into four broad categories. For the 219 studies that employed psychological measures, 151 (68.9%) reported significant positive outcomes, 22 (10.0%) non-significant or mixed outcomes, no studies reported negative outcomes, and 46 studies (21.0%) reported outcomes that were too complex to be easily classified. For the 135 studies that employed physiological measures, 83 (61.5%) reported significant positive outcomes, 28 (20.7%) non-significant or mixed outcomes, 1 (0.7%) negative outcome (where the forest therapy engagement unexpectedly increased heart rate/arousal, [93]), and 23 (17.0%) whose outcomes were too complex to be easily summarized.

3.3. Human Component

3.3.1. Human Characteristics Studied

Table 2 provides participant sample statistics across the entire set of articles. Because of the wide range of sample variability across the articles, the median statistic is a more representative indication of participant sample size (Mdn = 38.5) and average age (Mdn = 35), though it is noteworthy that a considerable number of studies were based on groups of 20 or less (n = 71, 28.1%), under 25 years of age (n = 93, 36.9%), and made up of either all male or all female participants (n = 69, 27.4%).
We categorized study samples used in the articles by the populations from which they were drawn, the two largest of which were young adults and university students (n = 85, 33.7%) [63,97] and broadly defined samples of adults or mixed adult and student samples (n = 76, 30.2%) [98,99]. In contrast to these general samples, smaller sets of articles targeted specific populations of interest, including middle-aged and older adults (n = 27, 10.8%) [76,100], youth and families (n = 19, 7.6%) [101,102], forest visitors (n = 19, 7.5%) [55,103], forest therapy and healthcare providers (n = 14, 5.6%) [50,69], and healthcare recipients (n = 10, 4.0%) [46,104].
A few of these targeted populations matched with particular health or wellbeing concerns that were the focus of a subset of studies (n = 76). We categorized this smaller set of studies into five areas of concern: mental health issues (n = 28, 36.9%) such as severe stress/exhaustion [105,106] and trauma/PTSD [34,87]; chronic diseases (n = 24, 31.4%) such as hypertension [65,72] and cancer [47,107]; youth issues (n = 10, 13.0%) such as youth who are placed at-risk [82,108] and those with learning difficulties [109,110]; individuals dealing with chronic pain or fatigue (n = 8, 10.4%) [111,112]; and those dealing with addictions (n = 4, 5.2%) [113,114].
Beyond these basic demographic and health-related characteristics, a few studies employing survey methods asked current and potential participants questions about their needs, motivations, and experience preferences with respect to forest therapy programs. Lee et al. [107] and Park [115] both conducted analyses of individuals challenged with disease about the types of programs that would best suit their needs with respect to activities, costs, and other factors. Choi [116] asked university students about their motivations and Kil et al. [55] asked onsite visitors about their recreation experience preferences for forest therapy engagements. In each of these cases the investigators aimed to better understand how programs and opportunities could be better geared to particular needs and preferences to achieve desired outcomes.

3.3.2. Human-Outcome Effects

The prevalence of articles in our full set with small, homogeneous samples is likely due to the fact that many experimental studies (the largest proportion of articles in our review set) can be labor intensive, especially when complex physiological data are collected, and by drawing from a homogeneous pool of participants in a within-subjects research design, often only small samples are needed to demonstrate statistical significance of a given outcome [117]. The disadvantage of such designs, however, is that they limit the ability to identify differences among subgroups of individuals that might respond differently to forest therapy engagements. Across all articles, we identified only 41 (16.1%) that examined differences between subgroups.
Most often these between-subject comparisons were across demographic variables in experimental studies and survey research with relatively large, broadly drawn participant samples. For example, in a large-scale population survey of Japanese residents, Morita et al. [118] found that male and older residents engaged in forest walking more frequently than female and younger residents. Additionally, in Japan, an onsite survey by Zhang et al. [56] found that female and older visitors to a National Recreational Forest placed higher emphasis on pavement conditions and degree of difficulty in selecting a trail for forest bathing than male and younger visitors. Additionally, in the UK, Marselle et al. [67] reported that frequent participants in the national Walking for Health program tended to be older, female, married, and living in the more affluent areas of the UK. While these observed differences relate to issues of site preference and use, for studies looking at other outcome variables, differences between demographic groups were not significant. For example, Kil et al. [55] found for forest bathers at South Korean forests that neither age, gender, education, nor income were significant predictors of place attachment, and in an image analysis of facial expressions of visitors to urban greenspaces in China, Liu et al. [119] found that happiness scores showed no differences by age or gender.
Beyond demographic differences, other studies have investigated and identified significant subgroup differences in outcomes as a function of A-B personality type [120], high-normal-low trait anxiety levels [121], and for those who lived and worked in forests versus urban settings [73]. A few studies in our sample examined forest therapy sites in multiple countries [103,122], but any differences were attributable more to site characteristics than the cross-national or cultural differences of participants. In contrast, while no cultural differences were explicitly compared in a survey of Malaysian students about forest therapy programs by Rajoo et al. [123], nearly 20% of the sample stated they were not interested in participating because the “animistic” association of forest bathing was against their religious beliefs and would create a negative social stigma in their conservative society.

3.4. Forest Component

3.4.1. Overall Forest Characteristics Studied

To address the forest component of our framework, we first examined the overall nature of the setting used as the basis of forest therapy engagements. In terms of landscape type, the large majority of studies were logically set in forest landscapes (n = 185, 73.7%), with successively fewer studies set in gardens (n = 29, 11.6%), including forest therapy gardens [87,124], botanic gardens [110,125], and arboreta [44,126]; mixed landscape types (n = 16, 6.4%) that often included forest areas along with non-forested landscapes such as meadows or agricultural land [127,128]; urban park and greenspace (n = 10, 4.0%) [129,130]; and other landscape types (n = 11, 4.4%) including deserts and wetlands [93,131]. Of the subset of studies set in forest environments (n = 185), forest types were broadly classified as dominantly coniferous (n = 23, 12.4%) [132,133], deciduous (n = 21, 11.4%) [134,135], mixed coniferous-deciduous (n = 53, 28.6%) [136,137], bamboo (n = 7, 3.8%) [63,138], or were unspecified (n = 81, 43.8%). Additionally, with respect to location, studies were set in rural (n = 105, 45.1%) [83,139], urban (n = 89, 38.2%) [84,140], mixed rural-urban (n = 25, 10.7%) [141,142], or were virtual studies without a specified location (n = 14, 6.0%) [143,144]. Along with these broad categorizations, the settings of 54 studies were identified as designated forest bathing or forest therapy sites, mainly in Japan [145,146], South Korea [108,111], and China [63,147].
We also sought to understand the quantitative dimensions of sites and trails used in forest therapy engagements for articles that reported them. As with the participant sample statistics reported earlier (Table 2), there was a wide variation in site characteristics and so we report median values here and refer readers to Table 3 for the full statistical summary. Most studies focused on a single site, and for the studies that reported their size (n = 67) the median size of smallest and largest sites ranged from 222–325 ha. Many studies included sites with multiple trails, although it was not always clear how many of the trails in the network at a site or across multiple sites were studied in the research. For the studies that reported trail lengths (n = 56), the median length of shortest and longest trails ranged from 2.0–2.9 km.

3.4.2. Key Forest Features and Qualities

A key aim of our Forest Therapy Trails project is to better understand the physical features and qualities of forest settings that facilitate multisensory, immersive experiences, and text analysis of forest setting descriptions in our article set provided further insights into the kinds of places that are being studied and used for forest therapy. As an indicator of descriptive detail, the word count of forest setting descriptions excerpted from the text of articles varied widely, with a median length of 30 words (M = 62.7, SD = 91.9) and with 42 articles (16.8%) offering no description outside of the mention of the name and/or location of the site. Another 68 articles (27.2%) offered only brief descriptions of 1–20 words conveying a few basic facts about the site such as forest type or location characteristics such as geographic coordinates and elevation. 84 articles (33.6%) offered what might be considered ample descriptions of 21–100 words that included information seen in brief descriptions plus details on characteristic tree species, average tree age/size, key site features, and/or trail characteristics. At the upper end, 56 articles (22.4%) offered extensive descriptions of 202–897 words that usually included all of the previously described information plus special or unique features, historical information, and/or detailed descriptions of multiple sites.
It was primarily from the more detailed descriptions (n = 134 articles, 53.2%) that we compiled a list of notable features mentioned by authors about the sites used they for forest therapy research (Table 4). The top five most frequently mentioned features included water (e.g., waterfalls, streams with drinkable waters, therapeutic mineral springs), vegetation diversity (e.g., diverse vegetation communities, high species richness and abundance, 350 species of native and exotic trees and shrubs), designated or protected status (e.g., AAAA-level scenic area, first national healing forest in the country, forest therapy base, national park), naturalness (e.g., native forest, outstanding natural location, wild forest garden), and large trees (e.g., semi-ancient woodland, trees up to 180 years old, 300 year-old trees). Other types of attributes ranged from physical features such as terrain and fauna, to access and support facilities, to visual and extra-visual qualities.
Building upon this by-article analysis, we used a frequency listing of terms extracted from a lexicometric analysis of forest setting descriptions to manually group terms into logical themes, four of which related to key features and characteristics of the forest setting: natural landscape, cultural landscape, evaluative, and viewscape (Table 5). Additional identified themes (landscape types, forest vegetation species, measurement units, places, weather, and activities) were less central to our purpose or were duplicative of other analyses and are not presented here.
The natural landscape theme (n = 62 terms, 771 total occurrences) included terms that were used to describe key features of the natural landscape of forest settings. Subthemes included vegetation (e.g., trees, plants, groundcover), water (e.g., waterfall, stream, lake), landform (e.g., level, slope, mountain), rock (rock, outcrop, karst), and wildlife (animals, habitat). The cultural landscape theme (56 terms, 414 occurrences) included terms relating to built and cultural features or elements of the forest setting. Subthemes included trails (e.g., trail, route, path), support facilities (e.g., shelter, bridges, stairs), people (e.g., people, visitors, tourists), interpretation (e.g., signs, interpretive, educational), and cultural/heritage (e.g., cultural, heritage, birthplace). The evaluative theme (60 terms, 575 occurrences) grouped together terms used to describe characteristics of setting quality. Subthemes included size/age (e.g., old, large, small), natural (e.g., natural, undisturbed, wild), dominance (e.g., dominated, dense, sparse), variety (e.g., varied, diverse, different), superlative (e.g., best, famous, excellent), beauty (e.g., beautiful, scenic, pleasant), condition (e.g., suitable, good, dead), and uniqueness (e.g., special, unique, common). Additionally, the viewscape theme (36 terms, 290 occurrences) included terms used to describe spatial and sensory characteristics of the landscape. Subthemes included spatial (e.g., surrounded, open, canopied), visual (e.g., views, light, scenes), and extra-visual (e.g., sensory, sounds, aromatic).

3.4.3. Forest-Outcome Effects

We were especially interested in understanding how particular forest setting characteristics and features related to the outcomes of forest therapy engagements. However, only a relatively small proportion of studies (n = 50, 19.1%) examined how variations within some aspect of the forest setting influenced health and wellbeing outcomes (Table 6). For this subset, the characteristics of forest settings that were examined included variations by forest stand [164,169] and landscape type [133,170]; comparisons between different spatial and structural characteristics of forest settings [58,171]; and gradient effects including level of management [74,149], degree of naturalness [122,142], and seasonality [72,134].
More often, the forest setting was considered in its totality, with health or wellbeing outcomes assessed without reference to variations within any setting characteristics (n = 100, 38.3%), usually before and after a forest therapy engagement. Other studies compared a generically described forest to an equally generic urban setting (n = 64, 24.5%) such as a busy street [102,129] or campus hardscape devoid of vegetation [172,173], or to a control condition (n = 29, 11.1%) such as pursuing normal daily activities [174] or attending an indoor program [113,152] in order to compare outcomes. Yet, another category of studies used some form of virtual media (n = 19, 7.3%) to compare forest representations with virtual urban [71,175] or control conditions [98,144] or with actual forest settings [176,177].
While the majority of studies that compared generic forest settings with urban or control settings found significant differences favoring positive outcomes in forest settings, those studies that examined variations within forest settings reported fewer significant positive and more non-significant or mixed outcomes (Table 6). For example, with respect to forest stand type, Guan et al. [164] found that forest bathers in an urban park in Northeast China experienced reduced anxiety after visiting stands dominated by either birch, maple, or oak, though stand-specific anxiety reduction varied inconsistently depending on the nature of the stressor (e.g., employment worries, university assignments). Similarly, Liu et al. [178] found that participants who walked in a National Forest Park near Beijing, China, experienced greater psychological restoration and mood improvement in a coniferous forest stand compared with deciduous or mixed forest types, while reductions in blood pressure and heart rate were greater in mixed forests. Looking at the effects of management, Arnberger et al. [74] found that visitors to alpine meadows in Austria and Switzerland exhibited no differences in physiological (blood pressure) and psychological (attention restoration, stress reduction, wellbeing) outcomes between managed and unmanaged sites. In contrast, Lee et al. [149] found South Korean women with metabolic syndrome who participated in a half-day forest healing program at a wild Recreational Forest showed significantly better biophysical and psychological improvements than those who attended the same program in a tended urban forest in Seoul. With respect to landscape type, Marselle et al. [170] found that individuals from across the UK who took frequent group walks in natural environments reported similar positive outcomes with respect to psychological measures of wellbeing, depression, perceived stress, and moods across six different landscape types (natural and semi-natural places, green corridors, farmland, urban green space, coastal, urban public space, and mixed-use landscapes). Additionally, while Sonntag-Öström et al. [105,133] similarly found that participants in a forest therapy program at a boreal forest in northern Sweden experienced mood improvement irrespective of the type of landscape they chose to spend time in (forest/lake, pine forest, rock outcrop, mixed forest, spruce forest, forest/stream), there were definite preferences for certain types over others.
These examples illustrate the range of positive and mixed or non-significant outcomes found in studies where within-forest setting comparisons were made. While the small number of studies and wide range of forest, human, interaction, and outcome measures studied prevent a more systematic analysis, one informal observation is that studies examining outcomes such as site suitability and preference were more likely to distinguish differences between forest settings than studies employing standardized psychological and physiological measures. This is not surprising, as expert-based suitability analyses [58,59] and participant-based preference assessments [75,179] are usually designed to discriminate between settings. Thus for helping to identify important features and qualities of forest settings, these types of outcome measures may display greater sensitivity than standardized psychological scales and physiological measures.

3.5. Interaction Component

3.5.1. Interaction Characteristics Studied

Consistent with our article search criteria and the objectives of our Forest Therapy Trails project, about three-quarters of the articles we reviewed focused on walking as a means of interacting with the forest setting (Table 7). In about a third of studies, participants sat or stood stationary to view the forest, while close to half included other activities besides walking or stationary viewing. Percentages in the table indicate that about half of the studies employed more than one of these major categories of forest engagement.
Looking more closely at other activities besides walking and stationary viewing, we identified a wide range of ways in which researchers or facilitators engaged forest therapy participants with the forest setting for achieving health and wellbeing outcomes. Foremost were relaxation activities (e.g., lying in a hammock, listening to music in the forest, stretching, yoga); “five senses” exercises to facilitate the multi-sensory, immersive experience (e.g., barefoot walking, aromatherapy, sitting by a waterfall); meditation or seated contemplation; group conversation and sharing (e.g., sitting around a campfire, sharing what one noticed or felt after a walk); purposeful hands-on engagement with nature (e.g., harvesting vegetables, wood splitting, tree planting); and nature-based arts and crafts activities (e.g., photography, making a mandala with leaves, self-expression using natural materials).
The number of “other” activities engaged in varied substantially by the main research activity type described in articles, as did other structural dimensions of the engagement as shown in Table 8 (forest experiences (n = 5) and forest air (n = 5) data not reported). For example, referring to the median values in the table, forest bathing engagements usually involved a single session of walking and or sitting for less than an hour with no other activities, while forest therapy engagements involved a program of six, three-hour sessions that included three other activities. However, as the Table 8 shows, there was a wide variation both within and between the major research activity types.
As for the social dimensions of engagements, those studies reporting group sizes (n = 183) ranged from a median of one for virtual studies and two for forest walks to six for forest bathing and nine for forest therapy engagements. On the lower end, group sizes for some activity types such as forest walks and virtual studies seemed in large part to be an artifact of the research protocols employed in many experimental studies to ensure independent assessments of outcomes [181,203] and/or because of complex equipment needs and measurements taken before, during, and/or after the engagement [204,205]. This included a number of studies where participants walked in or viewed the forest as a group but were instructed to keep their distance from each other and avoid interaction, for which we coded a group size of one [97,206]. On the upper end, larger group sizes tended to be from studies of forest therapy where social interaction among group participants was an explicit part of the program in helping realize health and wellbeing outcomes [123,140]. Few of these studies offered explanations for their choice of group size; the most frequent set of reasons of those that did was to reduce risk and crowding and/or to ensure a quality experience for participants (n = 10 [80]; n = 12 [137]; n = 16 [207]). In other cases, we informally observed that there were somewhat smaller group sizes for programs aimed at special populations such as youth placed at-risk (n = 8 [196]) and adults being treated with severe stress-related illnesses (n = 6 [155,179]).
Another social dimension of interest was whether forest engagements were facilitated by a forest therapy guide or other health or environmental professional. Looking across the major activity types, the highest proportion of studies where guides were part of the engagement was for forest therapy programs (n = 86, 68.6%), followed by forest experiences (n = 2, 50.0%), forest walks (n = 51, 35.3%), forest bathing (n = 65, 24.6%) and virtual studies (n = 17, 0.0%). Similar to the statistics for forest therapy programs reported in Table 8, studies that made use of a guide (n = 94) tended to include a number of longer sessions that engaged participants in multiple activities, whereas unguided engagements (n = 127) tended to be short, one-time affairs limited to walking or stationary viewing.

3.5.2. Interaction-Outcome Effects

As was the case with human and forest components, relatively few studies examined how differences between interaction variables affected health and wellbeing outcomes. The most frequent comparison was made among different forest engagement activities, especially forest walking and forest viewing. Unfortunately, the majority of studies that examined both walking and viewing focused instead on reporting forest versus urban differences and did not report statistical comparisons between the two forest-based activities [135,208,209], but those that did showed mixed effects on outcomes. In studying the psychological outcomes of forest engagements, Kobayashi et al. [210] found that participants who walked for 15 min along a 1 km forest trail in one of five different forest areas in Japan reported feeling higher vigor and lower fatigue and confusion as assessed by POMS scores than when they sat and viewed the same landscape for an equivalent time. However, no differences were found between the two engagement activities on POMS scores for tension-anxiety, depression-dejection, or anger-hostility. In contrast, Lyu et al. [166] found no differences in any of the POMS dimensions between participants who walked or viewed bamboo forest sites in China. In studying physiological outcomes, earlier studies by Kobayashi and colleagues using a similar research design and locations found that participant data on heart rate variability indicated significantly greater relaxation after viewing forests than after walking in them [211] but that levels of salivary cortisol indicated stress did not differ significantly between the two engagement types [212]. Additionally, Zeng et al. [153] concluded that viewing bamboo forests in China resulted in better physiological outcomes than walking in them, but study data showed only limited evidence of this difference for increased oxygen saturation in one of three forest sites studied and no differences between engagement type for blood pressure (SBP and DBP) or heart rate.
Beyond these focused comparisons of walking and viewing, there were a few studies that compared other forest therapy activities with similar non-forest-therapy activities also conducted within forest settings, such as green exercise [78], traditional qigong [100], and compassionate mind training [80]. Findings here were also mixed but tended to show that forest therapy and alternative therapies both led to similar, positive psychological and physiological outcomes. Additionally, in a unique study comparing a range of different forest bathing activities, Fu et al. [213] used wearable sensors to collect continuous physiological data from participants as they were guided in a 2 h forest bathing experience at a forest in Canada, with activities and locations along the route each designed to stimulate the five senses. The investigators found many similar, positive effects and also some significant differences in physiological measures between several activity-location segments, notably the lowest skin temperature (increased focus and attention) and highest electrodermal activity (increased arousal) during the barefoot walking segment of the engagement.
In addition to forest engagement activities, a few studies compared the effect of guides and related informational interventions on forest outcomes, again with no definitive findings on the superiority of one type of engagement over the other. Igawahara et al. [214] examined psychological and physiological effects of guided versus solo forest walks in Japan. The authors found greater stress reduction from the guided walk as measured by salivary cortisol levels along with more positive emotional improvements along some POMS and semantic differential (SD) subscales, though differences along other subscales were not significant. Lim et al. [160] found no significant differences in quantitative measures of nature connectedness, mood, or heart rate between participants of guided versus unguided forest therapy walks in Singapore. However, qualitative responses from guided participants more often described their experience as refreshing, meaningful, and unique, while unguided participants more often described it as positive, mindfulness of wildlife and nature, and alert/refreshed. Kim and Shin [36] compared themes coded from essays of participants in guided forest therapy groups in South Korea with those of self-guided individuals and found that more essays from solo participants mentioned auditory elements, although other sensory perceptions did not differ. Self-guided therapy led to greater introspection while guided therapy programs yielded greater positive emotion and social interaction, though other health benefits showed no differences due to the type of forest therapy. Additionally, Korcz et al. [215] compared the responses of participants who engaged in a 10 min forest walk through a managed urban forest in Poland either alone, with a forest educator as interpretive guide, or with the aid of educational boards posted along the route describing management activities. The authors reported improved wellbeing and psychological restoration for all participant groups, with little difference found on account of educational treatment.
As a final note on interaction outcomes, while no formal comparisons were made in the studies we reviewed, we did identify several studies that sought to measure outcome effects beyond typical pre/post assessments. These tended to be multi-session forest therapy programs that extended over several weeks in length, though a few were single-session forest bathing studies. For the 21 studies we identified that measured follow-up outcomes, engagements ranged in duration from a single 2 h session to daily and weekly hours-long programs up to 16 weeks in length, and with follow-up outcomes measured from 1 week up to 5 years after the completion of the engagement. Two short-term follow-ups examined physiological outcomes. Wang et al. [216] found that individuals who took a 2 h forest walk had significantly lower levels in a urinary biomarker of stress one day after the walk that remained low one week later. Kim et al. [194] found that women with breast cancer who participated in a daily forest therapy program for 2 weeks while living in the forest showed a significant increase in immune-response NK cell activity at the end of the program. While NK activity dropped 1 week after participants returned to their home in the city, anti-cancer blood proteins produced by NK cells continued to increase. Most of the longer-term follow-ups looked at the psychological outcomes of extended forest therapy programs. For example, Korpela et al. [161] found that individuals coping with depression experienced reduced depression and improved well-being at the completion of an 8-week nature walking program, with positive impacts extending to their 3-month follow-up. Sahlin et al. [200] found that participants in a 12-week nature-based stress management course showed decreased stress, burnout, and long-term sick leave, and increased work ability; these patterns persisted 6 months after the program and for some measures further improved 12 months after. Additionally, Pálsdóttir et al. [217], in a longitudinal study of individuals experiencing stress-related mental disorders who participated in a 12-week forest therapy program, found that nature smells had the effect of triggering sensory awareness and positive memories aiding in mental health recovery that in some cases persisted over the five-year follow-up period. Because of the small number of studies that examined these longer-term outcomes and the wide range of outcomes measured we were not able to quantify the relationship between the duration of engagements with the lasting effects of outcomes, but one study illustrates the potential limits of short-duration engagements. McEwan et al. [80] found that individuals who participated in a 2 h forest bathing experience showed improvements in positive emotions, mood, rumination, nature connection, and compassion immediately after the engagements. However, a 3-month follow-up showed that fears of compassion and rumination had increased and nature connection had decreased, with the authors concluding that regular practice is needed to maintain positive health and wellbeing outcomes.

4. Discussion

In this initial effort of our Forest Therapy Trails project, we adapted a framework from research in landscape perception [26] (Figure 1) to review empirical studies on forest therapy in relation to how human, forest, and interaction components are conceived and measured in the context of human health and wellbeing outcomes. While the 266 articles we identified were heavily dominated by experimental research designs and focused on outcomes, variations in these and other research approaches, the types of forest therapy activities studied, and other study details provided important insights into how human, forest, and interaction components have been investigated to date. In the following sections we reflect on the findings for each of these components and identify gaps and opportunities for future research.

4.1. Outcome Component

While our review identified a plethora of psychological and physiological measures used to assess the health and wellbeing outcomes of forest therapy engagements, most were aimed at a few broad concepts relating to mood-emotion and stress-arousal/relaxation. Specific psychological scales such as POMS and PANAS and physiological measures of blood pressure and salivary cortisol are long-established and validated, relatively easily to apply and interpret, and their wide use facilitates comparison of results across studies. For broadly drawn experimental designs such as pre-post assessments and comparisons between forest and urban settings, they also reliably yield positive results in support of forest therapy as a useful intervention for achieving health and wellbeing outcomes. While publication bias likely plays some role in the reporting of significant, positive results [218,219], one meta-analysis in the related area of garden therapy that corrected for underreporting of non-significant results concluded that it had little effect on the overall pattern of positive outcomes [220].
This consistency of findings across dozens of similar study replications in our review set leads us to conclude that further scholarly publication of basic, outcomes-focused assessments will be of diminishing utility unless studies speak to a fuller suite of outcome, human, forest, and interaction components described by our framework. Future work relating outcomes to the other framework components are discussed below but in considering outcomes alone, further work is needed in explicating less-studied outcomes directly and indirectly related to human health and wellbeing. For example, forest therapy engagements may lead to greater appreciation of the natural world, inspiring people to develop their environmental knowledge, outdoor skills, and become active in environmental protection activities [221,222,223], and studies exploring these outcomes and relationships could be fruitful not only in improving outcomes for the individuals involved but also for the natural world. Additionally, previous studies of people’s aesthetic, transcendent, and spiritual experiences in forests and other natural environments have many close parallels to the multi-sensory immersive experiences that define forest therapy engagements [224,225,226], and further qualitative research exploring these relationships could help expand the theoretical grounding for forest therapy. Finally, a few studies in our review set examined how forest therapy can be used in conjunction with mindfulness practice [80,227], and given the growing interest in each of these approaches in managing stress and becoming more fully present in an increasingly distracting world, further studies integrating these approaches would be useful [228,229].

4.2. Human Component

Consistent with the preponderance of experimental research designs, a large number of forest therapy studies in our review set were based on small samples of homogeneous participants, frequently university undergraduates. The use of pre/post, within-subject designs can be an efficient strategy for assessing the outcomes of an intervention, particularly in cases where complex physiological measures are taken. However, such studies provide little insight into broader questions of who participates in forest bathing and forest therapy programs, and, importantly, who currently does not. To the contrary, the few larger-scale experimental studies and surveys in the review set show that individuals who frequently participate in forest therapy, including forest bathing, forest walks, and other related activities, tend to be older adults [56,118], and in one UK study, came from more affluent areas [67]. Such findings, while in need of further validation, raise important issues with respect to access, not only to help ensure that trails and related support facilities are designed so that they are physically accessible for older adults [56], but to also ensure that forest therapy opportunities are economically accessible for all individuals who might benefit from healthful engagements in nature [128]. Forest therapy research could benefit from additional larger-scale studies to examine between-subject differences in needs, preferences, and outcomes as a function of other social, demographic, and stakeholder groups.
The wide international scope of forest therapy is testament to the power and potential that mindful, multi-sensory engagements in forests and other natural settings can have for individuals throughout the world who are dealing with the stressful realities of modern civilization. The global community of forest therapy researchers and practitioners have much to learn from countries like Japan and South Korea, which have not only mounted strong research programs to document the benefits of forest therapy but have developed networks of forest therapy bases to accommodate and encourage participation [12,230]. At the same time, there are likely important cultural differences in how forest therapy engagements are perceived and experienced, including hesitation by some individuals in conservative societies that certain activities may go against religious or societal norms [123]. An important next step in advancing forest therapy research would be to conduct cross-cultural investigations to understand to what extent there are differences in people’s nature experiences so that programs and opportunities can be designed to best meet the needs of particular cultural groups [231,232].
A strength of the studies we reviewed is the attention paid to particular groups of individuals with major health and wellbeing challenges, with more than a quarter of articles in our set focusing on some targeted population, ranging from older people living with chronic diseases [111,230], to veterans suffering post-traumatic stress [87,124], to youth who are placed at-risk [82,108]. Although the findings from these targeted investigations are highly encouraging in demonstrating the positive outcomes of forest therapy engagements, there is also a need to identify and begin to distinguish the characteristics of programs and facilities that are effective for groups facing different challenges. While programs can be flexibly adapted to meet the needs of special groups, facility design is somewhat less flexible, particularly for public facilities that must accommodate a wide variety of needs and preferences. In many cases, minimum standards for physical accessibility can help ensure that a trail can serve all individuals regardless of mobility issues [233]. However, it is also important for managers to think about going beyond minimum standards, to enhance experience of key features and qualities of the forest setting for groups such as individuals with sensory impairments, young children, and those with dementia. Whether they are general use or special use facilities, specific design considerations can aid in delivering desired health and wellbeing outcomes [234,235]. The need for program and design diversity also applies to individuals without major health challenges, where particular motivations and experience preferences point to the need for a spectrum of forest therapy opportunities [55].

4.3. Forest Component

The identification of key features and qualities of the forest setting is a primary goal of our Forest Therapy Trails project, and while the articles in our review set often provided only meager descriptions of the settings that were studied, our text analysis yielded a ranked list of notable features such as water, diverse vegetation, and big trees along with key themes relating to natural and cultural landscape features, evaluative dimensions, and viewscape qualities. Few studies attempted to relate specific features of forest settings to health and well-being outcomes, though nearly a third of studies compared forest therapy engagements with similar visits to urban settings, with the latter frequently portrayed as stark environments lacking natural features. A high proportion of these comparisons showed significant differences in health and wellbeing outcomes, with forest engagements improving psychological and physiological indicators and urban engagements resulting in no change or a worsening of outcomes. While such comparisons set a rather low bar for measuring the success of forest therapy interventions, it is also an unfortunate and increasingly common reality that many people live their daily lives in nature-impoverished urban hardscapes. Thus the findings of these studies make a strong case for increasing access to parks, greenspace and natural areas near people’s homes [236].
In contrast to these basic forest-urban comparisons, about 20% of the articles in our review set made within-forest comparisons of forest/landscape type, spatial-structure properties, level of management, and other characteristics. For these comparisons there was a much lower proportion of studies that found differences in outcomes between the conditions tested. One interpretation of these findings is that healthful engagements can be achieved in a wide range of forest settings and that their particular physical characteristics are less important than just being in green nature [170]. A parallel interpretation is that it is what you do in the forest setting that matters, and that with the proper frame of mind and/or facilitation by a forest therapy guide nearly any forest setting can provide sufficient stimulus for a healthful experience [1]. While both of these explanations can be true, it is also the case that certain characteristics of forest settings such as big trees and waterfalls are consistently associated with people’s landscape preferences and are reported to produce “peak” aesthetic and other highly valued experiences for people [226,237]. In our review we identified a small number of studies that looked at preference and suitability as outcome measures, which seemed better able to discriminate between forest setting characteristics than standardized psychological and physiological indicators [57,60,156]. However, there is also an extensive research literature on landscape perception and preference [30,238], that except for selected studies [75,239] has not been linked to forest therapy research to date. While a large proportion of landscape perception work is focused on the visual quality of landscapes and addresses a scale larger than the site-based features and multisensory qualities that we identified in our text analysis, a priority next step in our Forest Therapy Trails project is to sort through this literature for findings that have relevance to forest therapy site- and trail-based engagements.
By the same token, the articles in our review set provided little information in identifying other criteria important for forest therapy site selection and for trail design and construction. For example, environmental noise and other distractions were addressed as peripheral issues in a few studies [74,240], and it would be useful to examine relevant research on such topics as noise and tranquility mapping [241], solitude and privacy [242,243] and other factors that can facilitate peaceful engagements in forest settings. Access is another key issue: site selection factors such as proximity and cost can affect people’s ability to get to and use forest therapy sites [244,245], while design factors such as trail grade and surfacing can make sites accessible for users including older individuals and those with mobility impairments [246]. Again, such considerations were examined in only a few articles in our review set [40,115] and review of other work relating to trail choice preferences and design and construction standards could provide useful guidance for the siting and design of forest therapy trails.
In terms of future research relating to the forest component in our framework, studies in our article set that yielded the most useful information about salient features and qualities tended not to be experimental research but rather employed surveys with questions relating to site feature preferences [86,156], image analysis including feature identification and eye-tracking [204,247], expert assessments such as site inventories of key site attributes [59], and qualitative techniques such as content analysis of participants’ sketches [248] and observation of where participants spent time within a forest therapy site [249]. While this work constituted only a small fraction of the article set, the techniques employed are well-suited to identifying key features and qualities and further work of this type should be encouraged. Choice modeling is another tool that is especially well-suited to questions in this realm, and has been successfully used to identify key attributes of sites and trails in other recreational contexts [250].

4.4. Interaction Component

Our analysis found that forest therapy interactions varied widely in terms of activity types and number of activities engaged in, duration, group size, and guide facilitation, with notable differences in these structural and social dimensions as a function of whether investigators characterized the engagements they studied as forest bathing, a forest therapy program, or another major activity type. We were somewhat surprised by the limited nature of forest bathing interactions reported, with modal values reflecting more than 40% of the 59 studies in its activity type (Table 8) showing forest bathing as an unguided solo engagement of walking in or stationary viewing of forests for 15 min. In contrast, forest therapy studies tended to be longer duration, multi-activity group programs involving multiple sessions guided by a forest therapy expert. While the table statistics show variation both within and between these and other activity types, one observation between forest bathing and forest therapy studies is that the former tended to be set up as research experiments with the structural dimensions defined by the researcher while the latter were often established or pilot programs with the research serving more as a program evaluation. In the case of experimental studies of forest bathing, it is encouraging to see that even brief nature encounters appear to reliably produce a positive impact on people’s health and wellbeing, but for forest therapy practitioners it is important to note that the structural and social dimensions of interactions we reported may in part be an experimental artifact and may not be indicative of typical forest bathing. While there are good examples of actual programs examined in each of the major research activity types in our review set, further work on forest bathing and forest walks might fruitfully examine situations where engagements can be studied as natural experiments so that their findings are more translatable into practice [27].
While there were few studies in our review set that examined how differences in the ways people interact with forest settings affected health and wellbeing outcomes, those that did raise important questions for further research. In terms of person-forest interactions, work by Kobayashi et al. [210,211,212] and Zeng et al. [153] yielded somewhat ambiguous findings but seemed to indicate that stationary viewing activities may provide participants with a more relaxing experience while walks may increase vigor and lower fatigue. This sounds logical, but both walking and viewing are operationalized in many of the experimental studies as rather passive ways of person-forest interaction and may not invoke the fuller range of emotional, cognitive, and behavioral responses possible through more active interactions with forest settings [251]. For example, activities employed in some of the forest therapy programs we reviewed such as five-senses exercises [77,209], hands-on nature-based arts and crafts [252,253], and purposeful activities like picking vegetables and planting trees [34,254] invite actions that put participants in direct, intimate contact with nature. Such activities may extend the benefits of forest therapy engagements beyond typical psychological and physiological health benefits into other areas of wellbeing such as environmental learning and stewardship [255,256] and building reciprocal relationships between people and nature [257]. In our review set the study by Fu et al. [213] suggests one way in which research can begin to investigate how different types of interactions can affect people’s response to forests, and further exploration using a full range of quantitative and qualitative approaches is warranted.
People’s interactions with forests also take place in a social context, and studies in our set provided information regarding group size and guided versus unguided forest therapy engagements. Data from our analysis showed that median groups sizes varied by major activity type and tended to be highest for forest therapy programs, with explanations by investigators for limiting sizes to reduce risk and crowding and to maintain a quality experience. The research designs of many studies restricted engagements to one person at a time to maintain independence in the measurement of outcomes, and while this may tend to deflate group size estimates, the few studies that did explicitly compare guided group versus unguided solo engagements showed that each type of interaction can yield unique and beneficial outcomes [36,160,214]. One idea for improving knowledge about preferred types of social interactions and other aspects of forest engagements would be to include a few debriefing questions at the end of more formal outcomes assessments asking participants about their satisfaction with the experience and what might be done to improve it.

5. Conclusions

In this scoping review of empirical research in forest therapy we adapted a framework developed by Zube et al. [26] in the context of landscape perception research to better understand the human-forest interactions that lead to health and wellbeing outcomes. Based on their review, Zube et al. [26] proposed a set of considerations or principles that they concluded should drive further study in landscape perception. Building on their work, we summarize our own findings and recommendations in the following set of principles for helping guide forest therapy research and programs:
Forest therapy settings are multimodal, surrounding, information-rich environments. They invite movement and exploration and engage the participant. A goal for forest therapy research is to understand the full range of sensory information and experiences that forest settings can provide. A related goal of forest therapy programs is to facilitate the expansion of people’s umwelt through the provision of high-quality settings and interpretive information.
Forest therapy settings provide central and peripheral information. Information is received through direct attention to environmental stimuli as well as peripherally from outside the focus of attention, some of which can be distracting and interfere with desired forest therapy experiences and outcomes. A goal for forest therapy research and programs is to understand the factors that contribute to pleasing and healthful engagements while minimizing or avoiding negative factors.
People’s access to forest therapy settings and opportunities is varied. Access is influenced by physical factors such as proximity, individual abilities and comfort, and facility design; and by social factors such as cost, socio-demographic, and cultural differences. A goal of forest therapy research and programs is to work toward equity and inclusion for all who desire and can benefit from forest therapy engagements.
Forest therapy interactions have an ambience. Interactions arise in relation to aesthetic and systemic qualities of the setting and are mediated through various structural and social factors such as activity and whether one is alone and unguided or with a guided group. The goal of forest therapy research and programs is to better understand the ambient qualities of interactions and how they can best meet the preferences and constraints of individuals.
Meaningful forest therapy interactions can be highly variable. They can range from brief, passive, encounters while sitting or walking or can involve extended, multi-activity programs designed to actively engage individuals and groups to attain specific health and wellbeing outcomes. A goal of forest therapy research is to understand the unique and shared benefits of various interactions. A related goal of forest therapy practice is to provide programs and opportunities that serve people’s needs, including frequent short-term restoration and longer-term physical, emotional, and behavioral change.
Forest therapy engagements result in a range of health and wellbeing outcomes. Outcomes range from perceptual expressions of preference and choice; to psychological and physiological improvements in emotions, stress, and relaxation; to cognitive and behavioral changes that improve people as individuals and their relationships with the human and nonhuman world. A goal of forest therapy research and programs is to explicate and manifest the full range of outcomes.
In closing, we note some important limitations in our review. Our search strategy and coding procedures were largely confined to articles in English, which limited information that could be access and retrieved from studies reported in other languages, particularly pioneering work in forest therapy by Japanese and South Korean scholars. Additionally, while our coding strategy necessarily grouped some items within the human, landscape, interaction, and outcome categories into a manageable number of themes and subthemes, in doing so we acknowledge losing some important specificity that could help better understand the nature of forest therapy engagements. Additionally, while some coding categories we used represent discrete, independent concepts, we acknowledge that some measures used in forest therapy research tap multiple, interdependent dimensions of forest landscapes and people’s responses to them.


Author Contributions

Conceptualization, P.H.G., C.L.S., L.E.K. and J.R.H.; methodology, P.H.G.; formal analysis, P.H.G.; investigation, P.H.G. and C.L.S.; writing—original draft preparation, P.H.G.; writing—review and editing, P.H.G., C.L.S., L.E.K. and J.R.H.; project administration, J.R.H.; funding acquisition, P.H.G. and J.R.H. All authors have read and agreed to the published version of the manuscript.


This research was supported by Research Joint Venture Agreement 19-JV-11242309-040 between the USDA Forest Service Northern Research Station and Park Rx America. The APC was funded by the Northern Research Station.

Data Availability Statement

Not applicable.


The authors thank Tamberly Conway of Conservation Conexions and Amos Clifford of the Association of Nature and Forest Therapy for early discussions and encouragement in developing the Forest Therapy Trails project, Sonya Sachdeva of the USDA Forest Service and Sara Hadavi of Kansas State University for their helpful comments on an earlier draft of this paper, and Robert Zarr of Park Rx America for facilitating the research partnership.

Conflicts of Interest

The authors declare no conflict of interest.

Appendix A

Table A1. Summary characteristics of all articles in review (n = 266).
Table A1. Summary characteristics of all articles in review (n = 266).
Reference NumberCitationResearch TypeMain ActivityCountryLandscape TypeUrban-RuralAffiliation
[179]Adevi et al., 2018qualitativeforest therapySwedengardenurbanFor-Soc
[143]Alyan et al., 2021experimentalvirtualNAforestvirtualEnvSci
[201]An et al., 2019experimentalforest experienceChinaforesturbanForestry
[74]Arnberger et al., 2018experimentalforest therapyEuropemixedruralmissing
[258]Bach et al., 2021experimentalforest walksSpainforestruralMod-Soc-Env
[259]Bang et al., 2016experimentalforest walksS. KoreaforestmissingMedical
[199]Bang et al., 2017experimentalforest walksS. KoreaforesturbanMedical
[260]Bang et al., 2018experimentalforest therapyS. KoreaforesturbanMedical
[168]Baroqah et al., 2021experimentalforest therapyIndonesiaforestruralForestry
[261]Berger 2006qualitativeforest therapyIsraelgreenspaceurbanForestry
[109]Berger 2008qualitativeforest therapyIsraelgreenspaceurbanForestry
[187]Berger & Lahad 2010qualitativeforest therapyIsraelgreenspaceurbanForestry
[44]Berman et al., 2012experimentalforest walksUSgardenurbanSocSci
[134]Bielinis et al., 2018aexperimentalforest bathingPolandforesturbanForestry
[97]Bielinis et al., 2018bexperimentalforest bathingPolandforesturbanForestry
[262]Bielinis et al., 2019aexperimentalforest therapyPolandforesturbanFor-Soc-Env
[263]Bielinis et al., 2019bexperimentalforest bathingPolandforesturbanForestry
[104]Bielinis et al., 2020aexperimentalforest bathingPolandforesturbanFor-Soc
[175]Bielinis et al., 2020bexperimentalvirtualFinlandforestvirtualForestry
[172]Bielinis et al., 2021experimentalforest bathingFinlandforesturbanForestry
[129]Bratman et al., 2015experimentalforest walksUSparkurbanSoc-Env
[176]Calogiuri et al., 2018experimentalvirtualNorwaytrailurbanMed-Forest
[57]Capecchi et al., 2021expert assessmentforest therapyItalyforestruralFor-Soc
[83]Cervinka et al., 2020experimentalforest walksAustriaforestruralMed-Soc
[264]Cha & Kim 2009qualitativeforest experienceS. KoreaforestNSMedical
[79]Chan et al., 2021experimentalvirtualSingaporeforestvirtualSocSci
[207]Chen et al., 2018experimentalforest therapyTaiwanforestruralForestry
[116]Choi 2018surveyforest therapyS. Koreamissingmissingmissing
[11]Chou et al., 2021experimentalforest walksTaiwanforestruralForestry
[227]Clarke et al., 2021qualitativeforest bathingUKmissingmissingMed-Forest
[167]Conti 2019qualitativeforest experiencemissingmissingmissingmissing
[155]Corazon et al., 2018aexperimentalforest therapyDenmarkgardenurbanForestry
[113]Corazon et al., 2018bexperimentalforest therapyDenmarkgardenurbanMed-Forest
[144]Crossan & Salmoni 2021experimentalvirtualCanadaforestvirtualForestry
[127]Dahlan et al., 2021expert assessmentforest bathingIndonesiamixedruralForestry
[265]Davydenko & Peetz 2017experimentalforest walksCanadatrailurbanSocSci
[58]Dodev et al., 2021expert assessmentforest therapyBulgariaforestruralForestry
[266]Dolling et al., 2017experimentalforest therapySwedenforesturbanForestry
[139]Droli et al., 2021expert assessmentforest therapyItalyforestruralmissing
[46]Dybvik et al., 2018qualitativeforest therapyNorwaygardenruralmissing
[52]Edwards & Woods 2018qualitativeforest therapyCanadaforestruralMed-Soc
[184]Elsadek et al., 2021experimentalvirtualChinaforestNSForestry
[69]Farkić et al., 2020qualitativeforest experienceUKwaterruralForestry
[48]Farkić et al., 2021qualitativeforest bathingSerbiaforestruralFor-Soc
[213]Fu et al., 2022experimentalforest bathingCanadaforestruralMedical
[145]Furuyashik et al., 2019experimentalforest bathingJapanforestruralMedical
[204]Gao et al., 2021aexperimentalvirtualChinaforestvirtualForestry
[156]Gao et al., 2021bsurveyforest walksJapanforestruralForestry
[164]Guan et al., 2017experimentalforest bathingChinaforesturbanForestry
[88]Guyon F. 2020qualitativeforest bathingFranceforestruralmissing
[111]Han et al., 2016experimentalforest therapyS. KoreaforestruralMedical
[47]Harmon 2019qualitativeforest therapymissingforestNSmissing
[192]Hohashi & Kobayashi 2013experimentalforest bathingJapangardenurbanMedical
[101]Hong et al., 2021experimentalforest therapyS. KoreaforestruralForestry
[267]Horiuchi et al., 2015experimentalforest walksJapanforestruralMedical
[150]Huber et al., 2019experimentalforest therapyAustriawaterruralMedical
[214]Igawahara et al., 2007experimentalforest bathingJapanforestruralmissing
[268]Ikei et al., 2014experimentalforest therapyJapanforestruralMedical
[269]Ikei et al., 2015experimentalforest therapyJapanforestruralMedical
[98]Iwata et al., 2016experimentalforest walksIrelandvariousruralMed-Forest
[126]Izenstark et al., 2021experimentalforest walksUSgardenmissingSocSci
[180]Janeczko et al., 2020experimentalforest bathingPolandforesturbanMedical
[270]Jeon et al., 2018experimentalforest therapyS. KoreaforesturbanForestry
[108]Jeon et al., 2021experimentalforest therapyS. KoreaforestruralMed-Forest
[271]Jia et al., 2016experimentalforest bathingChinaforestruralMedical
[120]Jo et al., 2020experimentalforest therapyJapanforestruralMed-Forest
[183]Joung et al., 2015experimentalforest therapyS. KoreaforestmissingMed-For-Soc
[158]Joung et al., 2020experimentalforest bathingS. KoreaforestruralFor-Soc
[272]Joye et al., 2020experimentalvirtualEuropeforestvirtualSocSci
[186]Jung et al., 2015experimentalforest therapyS. KoreaforestruralMedical
[273]Kamitsis & Simmonds 2017qualitativeforest therapyvariousmissingmissingSocSci
[94]Kang B et al., 2015experimentalforest bathingS. KoreaforestmissingMedical
[191]Kang B.-H. & Shin 2020experimentalforest therapyS. KoreamixedurbanForestry
[99]Kang H. & Chae 2021experimentalforest therapyS. KoreamissingmissingMedical
[274]Kang H.W. & Lee 2021qualitativeforest therapyS. KoreaforestmissingMedical
[81]Kang S.-J. et al., 2021experimentalforest therapyS. KoreaforestruralMedical
[275]Keenan et al., 2021experimentalforest walksIrelandvariousruralSocSci
[55]Kil et al., 2021surveyforest bathingS. KoreaforestvariousForestry
[194]Kim B.J. et al., 2015experimentalforest therapyS. KoreaforestruralMed-Forest
[276]Kim G. et al., 2020expert assessmentforest airS. KoreaforestruralMed-Forest
[154]Kim H. et al., 2019experimentalforest therapyS. KoreaforestruralMedical
[185]Kim H. et al., 2020experimentalforest therapyS. KoreaforestruralMed-Soc
[82]Kim I.-O. et al., 2020experimentalforest therapyS. KoreaforestruralForestry
[277]Kim J.-C. et al., 2019experimentalforest airS. KoreamissingmissingEnvSci
[36]Kim J.-G. & Shin 2021experimentalforest therapyS. KoreaforesturbanForestry
[174]Kim J.-G. et al., 2020experimentalforest therapyS. KoreaforesturbanForestry
[278]Kim J.-G. et al., 2021experimentalforest therapyS. KoreaforesturbanForestry
[279]Kiper et al., 2016expert assessmentforest walksTurkeymixedruralForestry
[141]Kobayashi et al., 2015experimentalforest therapyJapanforestvariousMed-Forest
[211]Kobayashi et al., 2018experimentalforest walksJapanforestvariousMed-Forest
[212]Kobayashi et al., 2019experimentalforest walksJapanforestvariousMed-Forest
[210]Kobayashi et al., 2021experimentalforest walksJapanforestvariousMed-Forest
[68]Komppula et al., 2017qualitativeforest experienceFinlandmissingmissingmissing
[215]Korcz et al., 2021experimentalforest bathingPolandforesturbanForestry
[161]Korpela et al., 2016experimentalforest walksFinlandvariousurbanSocSci
[103]Korpela et al., 2017experimentalforest walksEuropeforestruralFor-Soc
[181]Koselka et al., 2019experimentalforest walksUSforesturbanMed-Soc
[198]Kotera & Fido 2021experimentalforest bathingJapanforestruralSocSci
[140]Lee H.J. et al., 2019qualitativeforest therapyS. KoreaforesturbanForestry
[280]Lee J. et al., 2011aexperimentalforest therapyJapanforesturbanMed-Forest
[45]Lee J. et al., 2011bexperimentalforest bathingJapanforestruralMed-Forest
[281]Lee J. et al., 2014experimentalforest walksJapanforestruralMedical
[188]Lee J.-H. et al., 2020experimentalforest therapyS. KoreaforesturbanForestry
[282]Lee J.-Y. et al., 2014experimentalforest walksS. KoreaforesturbanMedical
[149]Lee K.J. et al., 2018experimentalforest therapyS. KoreaforestvariousMedical
[107]Lee M.-M. et al., 2020surveyforest therapyS. KoreamissingmissingForestry
[197]Li C. et al., 2020experimentalvirtualChinaforestvirtualFor-Soc
[283]Li Q. et al., 2007experimentalforest bathingJapanforestruralMed-Forest
[284]Li Q. et al., 2008aexperimentalforest bathingJapanforestruralMed-Forest
[285]Li Q. et al., 2008bexperimentalforest bathingJapanforestruralMed-Forest
[286]Li Q. et al., 2011experimentalforest walksJapanforesturbanForestry
[287]Li Q. et al., 2016experimentalforest bathingJapanforestruralMed-Forest
[160]Lim P.Y. et al., 2020experimentalforest therapySingaporegardenurbanSocSci
[95]Lim Y.-S. et al., 2021experimentalforest therapyS. KoreaforesturbanMed-Forest
[147]Lin W et al., 2022experimentalforest walksChinaforesturbanForestry
[288]Liu P. et al., 2021aimage analysisforest therapyChinaforesturbanForestry
[119]Liu P. et al., 2021bimage analysisforest bathingChinaparkurbanForestry
[169]Liu Q. et al., 2021aexperimentalforest therapyChinaforesturbanFor-Env
[178]Liu Q. et al., 2021bexperimentalforest therapyChinaforesturbanFor-Env
[50]Lygum et al., 2019qualitativeforest therapyDenmarkgardenurbanForestry
[166]Lyu et al., 2019aexperimentalforest therapyChinaforestvariousForestry
[63]Lyu et al., 2019bexperimentalforest therapyChinaforestvariousForestry
[196]Macháčková et al., 2021experimentalforest bathingCzech Rep.forestNSForestry
[289]Mao G.-X. et al., 2012aexperimentalforest bathingChinaforestruralMed-Forest
[290]Mao G.-X. et al., 2012bexperimentalforest bathingChinaforesturbanMed-Forest
[92]Mao G.-X. et al., 2017experimentalforest bathingChinaforestruralMed-Forest
[233]Mao G.-X. et al., 2018experimentalforest bathingChinaforestruralMed-Forest
[291]Markwell & Gladwin 2020experimentalforest bathingUKforestNSSocSci
[67]Marselle et al., 2013experimentalforest walksUKvariousvariousMed-Forest
[292]Marselle et al., 2014experimentalforest walksUKvariousvariousMany
[170]Marselle et al., 2015experimentalforest walksUKvariousvariousMany
[142]Marselle et al., 2016experimentalforest walksUKvariousvariousMed-Soc
[293]Marselle et al., 2019experimentalforest walksUKvariousvariousMed-Env
[131]Maund et al., 2019experimentalforest therapyUKwaterruralFor-Soc-Env
[177]Mayer et al., 2009experimentalforest walksUSforesturbanSocSci
[85]McClain & Zimmerman 2014qualitativeforest walksUSforesturbanSocSci
[80]McEwan et al., 2021experimentalforest bathingUKforestruralFor-Soc
[122]Mena-García et al., 2020experimentalforest walksEuropevariousvariousSocSci
[294]Meneguzzo et al., 2019expert assessmentforest airItalyforestruralFor-Soc
[148]Meneguzzo et al., 2021experimentalforest therapyItalyforestruralMed-For-Soc
[60]Menser et al., 2021image analysisforest therapymissingmissingmissingMedical
[125]Meore et al., 2021experimentalforest walksUSgardenurbanMed-Forest
[138]Mihardja et al., 2021qualitativeforest bathingIndonesiaforestruralSocSci
[295]Morita et al., 2007experimentalforest bathingJapanforestruralMed-For-Soc
[163]Morita et al., 2009surveyforest walksJapanforestruralMed-Env
[157]Morita et al., 2011aexperimentalforest walksJapanforestruralMed-Soc
[296]Morita et al., 2011bsurveyforest walksJapanforestmissingMed-Soc
[118]Morita et al., 2013surveyforest walksJapanforestvariousMedical
[54]Morita et al., 2019surveyforest walksJapanforestmissingMed-Forest
[84]Muro et al., 2022experimentalforest bathingSpainforesturbanMed-For-Soc
[193]Nakau et al., 2013experimentalforest therapyJapanparkurbanMed-Forest
[89]Naor & Mayseless 2020qualitativeforest therapyvariousmissingmissingSocSci
[49]Naor & Mayseless 2021aqualitativeforest therapyvariousmissingmissingSocSci
[297]Naor & Mayseless 2021bqualitativeforest therapyvariousmissingmissingSocSci
[298]Naor & Mayseless 2021cqualitativeforest therapyvariousmissingmissingSocSci
[299]Nisbet & Zelenski 2011experimentalforest walksCanadatrailurbanSocSci
[76]Ochiai et al., 2015aexperimentalforest therapyJapanforestruralMed-Forest
[300]Ochiai et al., 2015bexperimentalforest therapyJapanforestruralMed-Forest
[114]Ochiai et al., 2020experimentalforest therapyJapanforestruralMed-Forest
[301]Oh et al., 2020qualitativeforest therapyS. KoreaforestvariousForestry
[12]Ohe et al., 2017experimentalforest therapyJapanforestruralFor-Soc
[302]Ohtsuka et al., 1998aexperimentalforest bathingJapanforestmissingMedical
[303]Ohtsuka et al., 1998bexperimentalforest bathingJapanforestmissingMedical
[217]Pálsdóttir et al., 2021qualitativeforest therapySwedengardenurbanFor-Env
[203]Park B.-J. et al., 2007experimentalforest bathingJapanforesturbanFor-Env
[136]Park B.-J. et al., 2008experimentalforest bathingJapanforestruralMed-Forest
[304]Park B.-J. et al., 2009experimentalforest bathingJapanforestmissingMedical
[208]Park B.-J. et al., 2011experimentalforest bathingJapanforestruralForestry
[305]Park B.-J. et al., 2014experimentalforest bathingJapanforestmissingMed-Forest
[306]Park B.-J. et al., 2020experimentalforest therapyS. KoreaforestruralFor-Soc
[115]Park K.-H. 2022surveyforest therapyS. KoreamissingmissingMedical
[90]Park S. et al., 2021bexperimentalforest therapyS. KoreaforestruralMed-Forest
[307]Pasanen et al., 2018experimentalforest walksFinlandgardenurbanFor-Soc
[64]Peterfalvi et al., 2021experimentalforest bathingHungaryforestruralMedical
[34]Poulsen et al., 2016experimentalforest therapyDenmarkgardenurbanmissing
[124]Poulsen et al., 2018experimentalforest therapyDenmarkgardenurbanForestry
[165]Pratiwi et al., 2019experimentalforest therapyJapanforesturbanFor-Env
[308]Pratiwi et al., 2020experimentalforest therapyJapanforesturbanForestry
[123]Rajoo et al., 2019experimentalforest therapyMalaysiaforesturbanFor-Env
[130]Rajoo et al., 2020bexperimentalforest therapyMalaysiaforesturbanFor-Env
[78]Rajoo et al., 2021experimentalforest therapyMalaysiaparkurbanForestry
[189]Ramshini et al., 2018experimentalforest therapyIrangreenspaceurbanSocSci
[70]Reese et al., 2022experimentalvirtualGermanyforesturbanSocSci
[62]Roviello & Roviello 2021aepidemiologicalforest bathingItalyvariousvariousEnvSci
[309]Roviello & Roviello 2021bepidemiologicalforest bathingItalyvariousvariousEnvSci
[310]Rozmi et al., 2020qualitativevirtualmissingforestvirtualSoc-Env
[200]Sahlin et al., 2014experimentalforest therapySwedenforestruralMed-Soc
[311]Saito et al., 2019experimentalforest bathingJapanforestruralMed-Env
[102]Schutte et al., 2017experimentalforest walksUStrailurbanSocSci
[93]Scott et al., 2021experimentalforest walksUSdesertruralFor-Soc
[190]Serrat et al., 2020experimentalforest therapySpainforestNSMed-For-Soc
[312]Shin W.S. et al., 2012experimentalforest therapyS. KoreaforestruralForestry
[66]Shin Y.-K. et al., 2013experimentalforest walksS. KoreaforestruralMed-Soc
[173]Shrestha et al., 2021experimentalforest walksIrelandtrailurbanSocSci
[87]Sidenius et al., 2017aqualitativeforest therapyDenmarkgardenurbanMed-For-Env
[51]Sidenius et al., 2017bqualitativeforest therapyDenmarkgardenurbanFor-Env
[313]Sidenius et al., 2020experimentalforest therapyDenmarkgardenurbanForestry
[314]Song et al., 2013aexperimentalforest bathingJapanforestvariousMedical
[315]Song et al., 2013bexperimentalforest walksJapanparkurbanMedical
[316]Song et al., 2014experimentalforest bathingJapanforestvariousMedical
[77]Song et al., 2015experimentalforest bathingJapanforestruralMed-Forest
[317]Song et al., 2016experimentalforest bathingJapanforestvariousMed-Forest
[65]Song et al., 2017aexperimentalforest bathingJapanforestruralMed-Forest
[91]Song et al., 2017bexperimentalforest therapyJapanforestruralMed-Forest
[318]Song et al., 2018aexperimentalvirtualJapanforestvirtualMed-Forest
[121]Song et al., 2018bexperimentalforest bathingJapanforestvariousMed-Forest
[319]Song et al., 2019aexperimentalforest bathingJapanforestruralMed-Forest
[320]Song et al., 2019bexperimentalforest bathingJapanforestruralMed-Forest
[321]Song et al., 2019cexperimentalvirtualJapanforestvirtualMed-Forest
[182]Song et al., 2020aexperimentalforest bathingJapanforestruralMed-Forest
[206]Song et al., 2020bexperimentalforest bathingJapanforestvariousMed-Forest
[205]Song et al., 2021experimentalvirtualJapanforestvirtualMed-Forest
[133]Sonntag-Öström et al., 2011experimentalforest therapySwedenforesturbanMedical
[322]Sonntag-Öström et al., 2014experimentalforest therapySwedenforesturbanMed-For-Soc
[323]Sonntag-Öström et al., 2015aexperimentalforest therapySwedenforesturbanMed-For-Env
[105]Sonntag-Öström et al., 2015bexperimentalforest therapySwedenforesturbanMed-For-Soc
[53]Spurio 2021qualitativeforest bathingItalyforesturbanSocSci
[247]Stevenson et al., 2019experimentalforest walksNorwaymixedruralMed-Forest
[110]Stevenson et al., 2021experimentalforest walksNew ZealandgardenurbanMedical
[151]Stigsdotter et al., 2017experimentalforest walksDenmarkgardenurbanFor-Soc
[106]Stigsdotter et al., 2018experimentalforest therapyDenmarkgardenurbanMed-For-Soc
[86]Suksri et al., 2021surveyforest walksThailandforestruralForestry
[159]Sung et al., 2012experimentalforest therapyS. KoreaforestruralMedical
[209]Takayama et al., 2014experimentalforest bathingJapanforestruralMed-Forest
[132]Takayama et al., 2017aexperimentalforest bathingJapanforestruralFor-Soc
[324]Takayama et al., 2017bexperimentalforest bathingJapanforestruralForestry
[325]Takayama et al., 2019experimentalforest bathingJapanforestruralForestry
[326]Takayama et al., 2022experimentalvirtualJapanforestvirtualFor-Env
[202]Thomas et al., 2020experimentalforest therapyAustraliagardenruralMedical
[73]Tsao et al., 2018experimentalforest airTaiwanforestruralMed-For-Env
[135]Tsunetsugu et al., 2007experimentalforest bathingJapanforestruralForestry
[248]Ueda & Takayama 2011qualitativeforest bathingJapanforestruralForestry
[327]Varning Poulsen et al., 2021qualitativeforest therapyDenmarkgardenurbanSocSci
[152]Vujcic et al., 2017experimentalforest therapySerbiagardenurbanFor-Soc
[254]Vujcic Trkulja et al., 2021experimentalforest therapySerbiagardenurbanFor-Soc
[59]Wajchman-Świtalska et al., 2021expert assessmentforest therapyPolandgardenurbanForestry
[328]Wang C. et al., 2019surveyforest therapyChinamissingmissingSocSci
[239]Wang D.-H. et al., 2018experimentalforest walksJapanforestruralMedical
[216]Wang X. et al., 2019experimentalvirtualChinaforestvirtualForestry
[128]Ware 2022qualitativeforest bathingCanadatrailruralArts
[329]Wei et al., 2019image analysisforest bathingChinaforesturbanEnvSci
[61]Wei et al., 2020image analysisforest bathingChinaforesturbanForestry
[240]Wei et al., 2021image analysisforest bathingChinagardenurbanMed-For-Env
[330]White et al., 2018qualitativeforest therapyUKgardenurbanMed-Env
[195]Willert et al., 2014experimentalforest therapyDenmarkgardenruralMedical
[331]Wu et al., 2019experimentalforest therapyChinaforestruralMed-Forest
[146]Yamada et al., 2020aexperimentalforest walksJapanforestruralMed-Soc
[332]Yamada et al., 2020bexperimentalforest walksJapanforestruralMedical
[333]Yamaguchi et al., 2006experimentalforest bathingJapanforestruralForestry
[96]Yi et al., 2019experimentalforest therapyS. KoreaforestmissingMed-Forest
[100]Yi et al., 2021experimentalforest therapyS. KoreaforesturbanMed-Forest
[253]Yu C.-P. & Hsieh 2020experimentalforest therapyTaiwangardenurbanMed-Forest
[137]Yu C.-P. et al., 2017experimentalforest bathingTaiwanforestruralMed-Forest
[37]Yu C.-P. et al., 2021experimentalforest therapyTaiwanforestruralMed-Forest
[252]Yu Y.-M. et al., 2016experimentalforest therapyS. KoreaforestruralForestry
[71]Zabini et al., 2020experimentalvirtualItalyforestvirtualMed-For-Soc
[153]Zeng et al., 2020experimentalforest therapyChinaforestvariousForestry
[171]Zhang J. et al., 2021image analysisforest bathingChinaparkurbanForestry
[249]Zhang T. et al., 2013surveyforest walksJapanforestruralmissing
[35]Zhang T. et al., 2015surveyforest bathingJapanforestruralForestry
[56]Zhang T. et al., 2019surveyforest bathingJapanforestruralForestry
[75]Zhang T. et al., 2020surveyforest bathingJapanforestruralForestry
[334]Zhou C. et al., 2019experimentalforest bathingChinaforestvariousMed-Forest
[72]Zhou Q. et al., 2021experimentalforest airChinaforesturbanForestry
[162]Zhu S.-X. et al., 2021expert assessmentforest airChinaforestruralForestry
[112]Zhu Z. et al., 2021experimentalforest therapyChinawaterruralMedical


  1. Clifford, M.A. Your Guide to Forest Bathing: Experience the Healing Power of Nature; Conari Press: Newburyport, MA, USA, 2018. [Google Scholar]
  2. Li, Q. Forest Bathing: How Trees Can Help You Find Health and Happiness; Viking: New York, NY, USA, 2018. [Google Scholar]
  3. Cooper, D.E. Forests, experience and the good life. In International Handbook of Forest Therapy; Kotte, D., Li, Q., Shin, W.S., Michalsen, A., Eds.; Cambridge Scholars Publishing: Newcastle upon Tyne, UK, 2021; pp. 2–11. [Google Scholar]
  4. Song, T. The Healing Nature Trail: Forest Bathing for Recovery and Awakening; Snow Wolf Publishing: Three Lakes, WI, USA, 2019. [Google Scholar]
  5. Miyazaki, Y. Shinrin Yoku: The Japanese Art of Forest Bathing; Timber Press: Portland, OR, USA, 2018. [Google Scholar]
  6. Yong, E. An Immense World: How Animal Senses Reveal the Hidden Realms Around Us; Random House: New York, NY, USA, 2022. [Google Scholar]
  7. Collins, D. Shinrin yoku—Just what the doctor ordered. For. Chron. 2016, 92, 512–513. [Google Scholar] [CrossRef][Green Version]
  8. La Puma, J. Nature therapy: An essential prescription for health. Altern. Complement. Ther. 2019, 25, 68–71. [Google Scholar] [CrossRef][Green Version]
  9. Park, B.J.; Tsunetsugu, Y.; Kasetani, T.; Kagawa, T.; Miyazaki, Y. The physiological effects of shinrin-yoku (taking in the forest atmosphere or forest bathing): Evidence from field experiments in 24 forests across Japan. Environ. Health Prev. Med. 2010, 15, 18–26. [Google Scholar] [CrossRef][Green Version]
  10. Rogerson, M.; Wood, C.; Pretty, J.; Schoenmakers, P.; Bloomfield, D.; Barton, J. Regular doses of nature: The efficacy of green exercise interventions for mental wellbeing. Int. J. Environ. Res. Public Health 2020, 17, 1526. [Google Scholar] [CrossRef][Green Version]
  11. Chou, W.-Y.; Hung, S.-H. Cumulative frequency of nature dose: How continuous and regular forest walking improves nature relatedness, restorativeness, and learning engagement in college students. Sustainability 2021, 13, 11370. [Google Scholar] [CrossRef]
  12. Ohe, Y.; Ikei, H.; Song, C.; Miyazaki, Y. Evaluating the relaxation effects of emerging forest-therapy tourism: A multidisciplinary approach. Tour. Manag. 2017, 62, 322–334. [Google Scholar] [CrossRef]
  13. Park, S.; Kim, S.; Kim, G.; Choi, Y.; Kim, E.; Paek, D. Evidence-based status of forest healing program in South Korea. Int. J. Environ. Res. Public Health 2020, 18, 10368. [Google Scholar] [CrossRef] [PubMed]
  14. Gobster, P.H.; Henderson, J.; Schultz, C.L.; Kruger, L.E. Developing Guidelines for the Design and Management of Forest Therapy Trails; Study Plan (Acquisition Project ID#: 504257); U.S. Department of Agriculture, Forest Service, Northern Research Station: Evanston, IL, USA, 2002.
  15. Doimo, I.; Masiero, M.; Gatto, P. Forest and wellbeing: Bridging medical and forest research for effective forest-based initiatives. Forests 2020, 11, 791. [Google Scholar] [CrossRef]
  16. Franco, L.S.; Shanahan, D.F.; Fuller, R.A. A review of the benefits of nature experiences: More than meets the eye. Int. J. Environ. Res. Public Health 2017, 14, 864. [Google Scholar] [CrossRef] [PubMed][Green Version]
  17. Pagès, A.B.; Peñuelas, J.; Clarà, J.; Llusià, J.; López, F.C.I.; Maneja, R. How should forests be characterized in regard to human health? Evidence from existing literature. Int. J. Environ. Res. Public Health 2020, 17, 1027. [Google Scholar] [CrossRef] [PubMed]
  18. Antonelli, M.; Donelli, D.; Carlone, L.; Maggini, V.; Firenzuoli, F.; Bedeschi, E. Effects of forest bathing (shinrin-yoku) on individual well-being: An umbrella review. Int. J. Environ. Health Res. 2021, 32, 1842–1867. [Google Scholar] [CrossRef] [PubMed]
  19. Kotera, Y.; Richardson, M.; Sheffield, D. Effects of shinrin-yoku (forest bathing) and nature therapy on mental health: A systematic review and meta-analysis. Int. J. Ment. Health Addict. 2022, 20, 337–361. [Google Scholar] [CrossRef]
  20. Oh, B.; Lee, K.J.; Zaslawski, C.; Yeung, A.; Rosenthal, D.; Larkey, L.; Back, M. Health and well-being benefits of spending time in forests: Systematic review. Environ. Health Prev. Med. 2017, 22, 71. [Google Scholar] [CrossRef][Green Version]
  21. Rajoo, K.S.; Karam, D.S.; Abdullah, M.Z. The physiological and psychosocial effects of forest therapy: A systematic review. Urban For. Urban Green. 2020, 54, 126744. [Google Scholar] [CrossRef]
  22. Stier-Jarmer, M.; Throner, V.; Kirschneck, M.; Immich, G.; Frisch, D.; Schuh, A. The psychological and physical effects of forests on human health: A systematic review of systematic reviews and meta-analyses. Int. J. Environ. Res. Public Health 2021, 18, 1770. [Google Scholar] [CrossRef] [PubMed]
  23. Wen, Y.; Yan, Q.; Pan, Y.; Gu, X.; Liu, Y. Medical empirical research on forest bathing (shinrin-yoku): A systematic review. Environ. Health Prev. Med. 2019, 24, 70. [Google Scholar] [CrossRef][Green Version]
  24. Grilli, G.; Sacchelli, S. Health benefits derived from forest: A review. Int. J. Environ. Res. Public Health 2020, 17, 6125. [Google Scholar] [CrossRef]
  25. Munn, Z.; Peters, M.D.J.; Stern, C.; Tufanaru, C.; McArthur, A.; Aromataris, E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med. Res. Methodol. 2018, 18, 143. [Google Scholar] [CrossRef]
  26. Zube, E.H.; Sell, J.L.; Taylor, J.G. Landscape perception: Research, application and theory. Landsc. Plan. 1982, 9, 1–33. [Google Scholar] [CrossRef]
  27. Bratman, G.N.; Anderson, C.B.; Berman, M.G.; Cochran, B.; de Vries, S.; Flanders, J.; Folke, C.; Frumkin, H.; Gross, J.J.; Daily, G.C. Nature and mental health: An ecosystem service perspective. Sci. Adv. 2019, 5, eaax0903. [Google Scholar] [CrossRef]
  28. Dewey, J.; Bentley, A.F. Knowing and the Known; Beacon: Boston, MA, USA, 1949. [Google Scholar]
  29. Ittelson, W.H. Environmental perception and contemporary perceptual theory. In Environmental Cognition; Ittelson, W.H., Ed.; Seminar Press: New York, NY, USA, 1973; pp. 1–19. [Google Scholar]
  30. Gobster, P.H.; Ribe, R.G.; Palmer, J.F. Themes and trends in visual assessment research: Introduction to the Landscape and Urban Planning special collection on the visual assessment of landscapes. Landsc. Urban Plan. 2019, 191, 103635. [Google Scholar] [CrossRef]
  31. Smardon, R. Ecosystem services for scenic quality landscape management: A review. Land 2021, 10, 1123. [Google Scholar] [CrossRef]
  32. Fan, R.; Fan, J.; Song, J.; Li, K.; Ji, W. Naturalness in the city: Demographic groups’ differences in preference for deciduous landscape. Sustainability 2021, 13, 7615. [Google Scholar] [CrossRef]
  33. Jiricka-Purrer, A.; Tadini, V.; Salak, B.; Taczanowska, K.; Tucki, A.; Senes, G. Do protected areas contribute to health and well-being? A cross-cultural comparison. Int. J. Environ. Res. Public Health 2019, 16, 1172. [Google Scholar] [CrossRef][Green Version]
  34. Poulsen, D.V.; Stigsdotter, U.K.; Djernis, D.; Sidenius, U. ‘Everything just seems much more right in nature’: How veterans with post-traumatic stress disorder experience nature-based activities in a forest therapy garden. Health Psych. Open 2016, 3, 2055102916637090. [Google Scholar] [CrossRef][Green Version]
  35. Zhang, T.; Deng, S.; Ma, Q.; Sasaki, K. Evaluations of landscape locations along trails based on walking experiences and distances traveled in the Akasawa Forest Therapy Base, Central Japan. Forests 2015, 6, 2853–2878. [Google Scholar] [CrossRef][Green Version]
  36. Kim, J.-G.; Shin, W.-S. Forest therapy alone or with a guide: Is there a difference between self-guided forest therapy and guided forest therapy programs? Int. J. Environ. Res. Public Health 2021, 18, 6957. [Google Scholar] [CrossRef] [PubMed]
  37. Yu, C.-P.; Chen, H.-T.; Chao, P.-H.; Yin, J.; Tsai, M.-J. The role of social context in physiological and psychological restoration in a forest: Case study of a guided forest therapy program in Taiwan. Int. J. Environ. Res. Public Health 2021, 18, 10076. [Google Scholar] [CrossRef] [PubMed]
  38. Kotera, Y.; Lyons, M.; Vione, K.C.; Norton, B. Effect of nature walks on depression and anxiety: A systematic review. Sustainability 2021, 13, 4015. [Google Scholar] [CrossRef]
  39. Mathias, S.; Daigle, P.; Dancause, K.N.; Gadais, T. Forest bathing: A narrative review of the effects on health for outdoor and environmental education use in Canada. J. Outdoor Environ. Educ. 2020, 23, 309–321. [Google Scholar] [CrossRef]
  40. Park, S.; Kim, E.; Kim, G.; Kim, S.; Choi, Y.; Paek, D. What activities in forests are beneficial for human health? A systematic review. Int. J. Environ. Res. Public Health 2022, 19, 2692. [Google Scholar] [CrossRef] [PubMed]
  41. Abrams, K.M.; Wang, Z.; Song, Y.J.; Galindo-Gonzalez, S. Data richness trade-offs between face-to-face, online audiovisual, and online text-only focus groups. Soc. Sci. Comput. Rev. 2015, 33, 80–96. [Google Scholar] [CrossRef]
  42. Onwuegbuzie, A.J.; Leech, N.L.; Collins, K.M. Qualitative analysis techniques for the review of the literature. Qual. Rep. 2012, 17, 56. [Google Scholar] [CrossRef]
  43. Van Eck, N.; Waltman, L. VOSviewer Manual, Version 1.6.9; Leiden University: Leiden, The Netherlands, 2018. [Google Scholar]
  44. Berman, M.G.; Kross, E.; Krpan, K.M.; Askren, M.K.; Burson, A.; Deldin, P.J.; Kaplan, S.; Sherdell, L.; Gotlib, I.H.; Jonides, J. Interacting with nature improves cognition and affect for individuals with depression. J. Affect. Disord. 2012, 140, 300–305. [Google Scholar] [CrossRef][Green Version]
  45. Lee, J.; Park, B.-J.; Tsunetsugu, Y.; Ohira, T.; Kagawa, T.; Miyazaki, Y. Effect of forest bathing on physiological and psychological responses in young Japanese male subjects. Public Health 2011, 125, 93–100. [Google Scholar] [CrossRef]
  46. Dybvik, J.B.; Sundsford, S.; Wang, C.E.A.; Nivison, M. Significance of nature in a clinical setting and its perceived therapeutic value from patients’ perspective. Eur. J. Psychother. Couns. 2018, 20, 429–449. [Google Scholar] [CrossRef][Green Version]
  47. Harmon, J. Tell cancer to take a hike: Post traumatic growth on the trail to recovery. Leisure/Loisir 2019, 43, 459–478. [Google Scholar] [CrossRef]
  48. Farkic, J.; Isailovic, G.; Taylor, S. Forest bathing as a mindful tourism practice. Ann. Tour. Res. Empir. Insights 2021, 2, 100028. [Google Scholar] [CrossRef]
  49. Naor, L.; Mayseless, O. The therapeutic process in nature-based therapies from the perspectives of facilitators: A qualitative inquiry. Ecopsychology 2021, 13, 284–293. [Google Scholar] [CrossRef]
  50. Lygum, V.L.; Poulsen, D.V.; Djernis, D.; Djernis, H.G.; Sidenius, U.; Stigsdotter, U.K. Post-occupancy evaluation of a crisis shelter garden and application of findings through the use of a participatory design process. Health Environ. Res. Des. J. 2019, 12, 153–167. [Google Scholar] [CrossRef]
  51. Sidenius, U.; Nyed, P.K.; Lygum, V.L.; Stigsdotter, U.K. A diagnostic post-occupancy evaluation of the Nacadia® therapy garden. Int. J. Environ. Res. Public Health 2017, 14, 882. [Google Scholar] [CrossRef] [PubMed][Green Version]
  52. Edwards, A.; Woods, V. Forest-based therapy: Research letter of a novel regime for improved respiratory health. Integr. Med. 2018, 17, 58–60. [Google Scholar]
  53. Spurio, M.G. Mourning from COVID-19 and post-traumatic stress disorder: New therapeutic tools in the treatment of pathological bereavement. Psychiatr. Danub. 2021, 33, 102–107. [Google Scholar]
  54. Morita, E.; Kadomatsu, Y.; Tsukamoto, M.; Kubo, Y.; Okada, R.; Sasakabe, T.; Kawai, S.; Hishida, A.; Naito, M.; Wakai, K. Frequency of forest walking is not associated with prevalence of hypertension based on cross-sectional studies of a general Japanese population: A reconfirmation by the J-MICC Daiko Study. Nagoya J. Med. Sci. 2019, 81, 489–500. [Google Scholar] [CrossRef]
  55. Kil, N.; Stein, T.V.; Holland, S.M.; Kim, J.J.; Kim, J.; Petitte, S. The role of place attachment in recreation experience and outcome preferences among forest bathers. J. Outdoor Recreat. Tour. 2021, 35, 100410. [Google Scholar] [CrossRef]
  56. Zhang, T.; Zhang, W.; Meng, H.; Zhang, Z. Analyzing visitors’ preferences and evaluation of satisfaction based on different attributes, with forest trails in the Akasawa National Recreational Forest, Central Japan. Forests 2019, 10, 431. [Google Scholar] [CrossRef][Green Version]
  57. Capecchi, I.; Grilli, G.; Barbierato, E.; Sacchelli, S. A spatial multi-criteria decision support system for stress recovery-oriented forest management. In Green Energy and Technology; Springer: Berlin/Heidelberg, Germany, 2021; pp. 171–184. [Google Scholar] [CrossRef]
  58. Dodev, Y.; Zhiyanski, M.; Glushkova, M.; Borisova, B.; Semerdzhieva, L.; Ihtimanski, I.; Dimitrov, S.; Nedko, S.; Nikolova, M.; Shin, W.-S. An integrated approach to assess the potential of forest areas for therapy services. Land 2021, 10, 1354. [Google Scholar] [CrossRef]
  59. Wajchman-Świtalska, S.; Zajadacz, A.; Lubarska, A. Recreation and therapy in urban forests—The potential use of sensory garden solutions. Forests 2021, 12, 1402. [Google Scholar] [CrossRef]
  60. Menser, T.; Baek, J.; Siahaan, J.; Kolman, J.M.; Delgado, D.; Kash, B. Validating visual stimuli of nature images and identifying the representative characteristics. Front. Psychol. 2021, 12, 685815. [Google Scholar] [CrossRef]
  61. Wei, H.; Ma, B.; Hauer, R.J.; Liu, C.; Chen, X.; He, X. Relationship between environmental factors and facial expressions of visitors during the urban forest experience. Urban For. Urban Green. 2020, 53, 126699. [Google Scholar] [CrossRef]
  62. Roviello, V.; Roviello, G.N. Lower COVID-19 mortality in Italian forested areas suggests immunoprotection by Mediterranean plants. Environ. Chem. Let. 2021, 19, 699–710. [Google Scholar] [CrossRef]
  63. Lyu, B.; Zeng, C.; Xie, S.; Li, D.; Lin, W.; Li, N.; Jiang, M.; Liu, S.; Chen, Q. Benefits of a three-day bamboo forest therapy session on the psychophysiology and immune system responses of male college students. Int. J. Environ. Res. Public Health 2019, 16, 4991. [Google Scholar] [CrossRef][Green Version]
  64. Peterfalvi, A.; Meggyes, M.; Makszin, L.; Farkas, N.; Miko, E.; Miseta, A.; Szereday, L. Forest bathing always makes sense: Blood pressure-lowering and immune system-balancing effects in late spring and winter in Central Europe. Int. J. Environ. Res. Public Health 2021, 18, 2067. [Google Scholar] [CrossRef] [PubMed]
  65. Song, C.; Ikei, H.; Kobayashi, M.; Miura, T.; Li, Q.; Kagawa, T.; Kumeda, S.; Imai, M.; Miyazaki, Y. Effects of viewing forest landscape on middle-aged hypertensive men. Urban For. Urban Green. 2017, 21, 247–252. [Google Scholar] [CrossRef]
  66. Shin, Y.-K.; Kim, D.J.; Jung-Choi, K.; Son, Y.-J.; Koo, J.-W.; Min, J.-A.; Chae, J.-H. Differences of psychological effects between meditative and athletic walking in a forest and gymnasium. Scand. J. For. Res. 2013, 28, 64–72. [Google Scholar] [CrossRef]
  67. Marselle, M.R.; Irvine, K.N.; Warber, S.L. Walking for well-being: Are group walks in certain types of natural environments better for well-being than group walks in urban environments? Int. J. Environ. Res. Public Health 2013, 10, 5603–5628. [Google Scholar] [CrossRef][Green Version]
  68. Komppula, R.; Konu, H.; Vikman, N. Listening to the sounds of silence: Forest based wellbeing tourism in Finland. In Nature Tourism; Chen, J.S., Prebensen, N.K., Eds.; Routledge: New York, NY, USA, 2017; pp. 120–130. [Google Scholar]
  69. Farkić, J.; Filep, S.; Taylor, S. Shaping tourists’ wellbeing through guided slow adventures. J. Sustain. Tour. 2020, 28, 2064–2080. [Google Scholar] [CrossRef]
  70. Reese, G.; Stahlberg, J.; Menzel, C. Digital shinrin-yoku: Do nature experiences in virtual reality reduce stress and increase well-being as strongly as similar experiences in a physical forest? Virtual Real. 2022, 26, 1–11. [Google Scholar] [CrossRef]
  71. Zabini, F.; Albanese, L.; Becheri, F.R.; Gavazzi, G.; Giganti, F.; Giovanelli, F.; Gronchi, G.; Viggiano, M.P. Comparative study of the restorative effects of forest and urban videos during Covid-19 lockdown: Intrinsic and benchmark values. Int. J. Environ. Res. Public Health 2020, 17, 8011. [Google Scholar] [CrossRef]
  72. Zhou, Q.; Wang, J.; Wu, Q.; Chen, Z.; Wang, G. Seasonal dynamics of VOCs released from Cinnamomun camphora forests and the associated adjuvant therapy for geriatric hypertension. Ind. Crops Prod. 2021, 174, 114131. [Google Scholar] [CrossRef]
  73. Tsao, T.-M.; Tsai, M.-J.; Hwang, J.-S.; Cheng, W.-F.; Wu, C.-F.; Chou, C.-C.; Su, T.-C. Health effects of a forest environment on natural killer cells in humans: An observational pilot study. Oncotarget 2018, 9, 16501–16511. [Google Scholar] [CrossRef] [PubMed]
  74. Arnberger, A.; Eder, R.; Allex, B.; Ebenberger, M.; Hutter, H.-P.; Wallner, P.; Bauer, N.; Zaller, J.G.; Frank, T. Health-related effects of short stays at mountain meadows, a river and an urban site—Results from a field experiment. Int. J. Environ. Res. Public Health 2018, 15, 2647. [Google Scholar] [CrossRef][Green Version]
  75. Zhang, T.; Deng, S.Q.; Gao, Y.; Zhang, Z.; Meng, H.; Zhang, W.K. Visitors’ satisfaction and evaluation to walk on the trails of forest: Evidence from the national forest of Akasawa, Japan. IOP Conf. Ser. Earth Environ. Sci. 2020, 594, 12004. [Google Scholar] [CrossRef]
  76. Ochiai, H.; Ikei, H.; Song, C.; Kobayashi, M.; Miura, T.; Kagawa, T.; Li, Q.; Kumeda, S.; Imai, M.; Miyazaki, Y. Physiological and psychological effects of a forest therapy program on middle-aged females. Int. J. Environ. Res. Public Health 2015, 12, 15222–15232. [Google Scholar] [CrossRef][Green Version]
  77. Song, C.; Ikei, H.; Kobayashi, M.; Miura, T.; Taue, M.; Kagawa, T.; Li, Q.; Kumeda, S.; Imai, M.; Miyazaki, Y. Effect of forest walking on autonomic nervous system activity in middle-aged hypertensive individuals: A pilot study. Int. J. Environ. Res. Public Health 2015, 12, 2687–2699. [Google Scholar] [CrossRef][Green Version]
  78. Rajoo, K.S.; Karam, D.S.; Abdu, A.; Rosli, Z.; Gerusu, J.G. Addressing psychosocial issues caused by the Covid-19 lockdown: Can urban greeneries help? Urban For. Urban Green. 2021, 65, 127340. [Google Scholar] [CrossRef]
  79. Chan, S.H.M.; Qiu, L.; Esposito, G.; Mai, K.P.; Tam, K.-P.; Cui, J. Nature in virtual reality improves mood and reduces stress: Evidence from young adults and senior citizens. Virtual Real. 2021, 25, 1–16. [Google Scholar] [CrossRef]
  80. McEwan, K.; Giles, D.; Clarke, F.J.; Kotera, Y.; Evans, G.; Terebenina, O.; Minou, L.; Teeling, C.; Basran, J.; Weil, D. A pragmatic controlled trial of forest bathing compared with compassionate mind training in the UK: Impacts on self-reported wellbeing and heart rate variability. Sustainability 2021, 13, 1380. [Google Scholar] [CrossRef]
  81. Kang, S.-J.; Kim, H.-S.; Baek, K.-H. Effects of nature-based group art therapy programs on stress, self-esteem and changes in electroencephalogram (EEG) in non-disabled siblings of children with disabilities. Int. J. Environ. Res. Public Health 2021, 18, 5912. [Google Scholar] [CrossRef]
  82. Kim, I.-O.; Shin, W.-S.; Jeon, J.Y. The effects of a forest therapy program on the self-esteem and resilience of juveniles under protective detention. J. People Plants Environ. 2020, 23, 485–494. [Google Scholar] [CrossRef]
  83. Cervinka, R.; Schwab, M.; Haluza, D. Investigating the qualities of a recreational forest: Findings from the cross-sectional Hallerwald case study. Int. J. Environ. Res. Public Health 2020, 17, 1676. [Google Scholar] [CrossRef] [PubMed]
  84. Muro, A.; Feliu-Soler, A.; Canals, J.; Parrado, E.; Sanz, A. Psychological benefits of forest bathing during the Covid-19 pandemic: A pilot study in a Mediterranean forest close to urban areas. J. For. Res. 2022, 27, 71–75. [Google Scholar] [CrossRef]
  85. McClain, L.R.; Zimmerman, H.T. Prior experiences shaping family science conversations at a nature center. Sci. Educ. 2014, 98, 1009–1032. [Google Scholar] [CrossRef]
  86. Suksri, C.; Phongkhieo, N.T.; Emphandhu, D. Environmental perception and learning experience in nature trail of national park visitors. Kasetsart J. Soc. Sci. 2021, 42, 339–344. [Google Scholar] [CrossRef]
  87. Sidenius, U.; Stigsdotter, U.K.; Poulsen, D.B.; Bonda, P. “I look at my own forest and fields in a different way”: The lived experience of nature-based therapy in a therapy garden when suffering from stress-related illness. Int. J. Qual. Stud. Health Well-Being 2017, 12, 1324700. [Google Scholar] [CrossRef][Green Version]
  88. Guyon, F. Roaming the mountain forests: Wandering to perfect the capacitive body. Rev. Geogr. Alpine 2020, 108, 1–17. [Google Scholar] [CrossRef]
  89. Naor, L.; Mayseless, O. The therapeutic value of experiencing spirituality in nature. Spiritual. Clin. Pract. 2020, 7, 114–133. [Google Scholar] [CrossRef]
  90. Park, S.; Choi, Y.; Kim, G.; Kim, E.; Kim, S.; Paek, D. Physiological and psychological assessments for the establishment of evidence-based forest healing programs Int. J. Environ. Res. Public Health 2021, 18, 9283. [Google Scholar] [CrossRef]
  91. Song, C.; Ikei, H.; Miyazaki, Y. Sustained effects of a forest therapy program on the blood pressure of office workers. Urban For. Urban Green. 2017, 27, 246–252. [Google Scholar] [CrossRef]
  92. Mao, G.; Cao, Y.; Wang, B.; Wang, S.; Chen, Z.; Wang, J.; Xing, W.; Ren, X.; Lv, X.; Yan, J. The salutary influence of forest bathing on elderly patients with chronic heart failure. Int. J. Environ. Res. Public Health 2017, 14, 368. [Google Scholar] [CrossRef][Green Version]
  93. Scott, E.E.; LoTemplio, S.B.; McDonnell, A.S.; McNay, G.D.; Greenberg, K.; McKinney, T.; Uchino, B.N.; Strayer, D.L. The autonomic nervous system in its natural environment: Immersion in nature is associated with changes in heart rate and heart rate variability. Psychophysiology 2021, 58, e13698. [Google Scholar] [CrossRef] [PubMed]
  94. Kang, B.; Kim, T.; Kim, M.J.; Lee, K.H.; Choi, S.; Lee, D.H.; Kim, H.R.; Jun, B.; Park, S.Y.; Park, S.-B. Relief of chronic posterior neck pain depending on the type of forest therapy: Comparison of the therapeutic effect of forest bathing alone versus forest bathing with exercise. Ann. Rehabil. Med. 2015, 39, 957–963. [Google Scholar] [CrossRef] [PubMed][Green Version]
  95. Lim, Y.-S.; Kim, J.; Khil, T.; Yi, J.; Kim, D.-J. Effects of the forest healing program on depression, cognition, and the autonomic nervous system in the elderly with cognitive decline. J. People Plants Environ. 2021, 24, 107–117. [Google Scholar] [CrossRef]
  96. Yi, J.; Ku, B.; Kim, S.G.; Khil, T.; Lim, Y.; Shin, M.; Jeon, S.; Kim, J.; Kang, B.; Kim, J.U. Traditional Korean medicine-based forest therapy programs providing electrophysiological benefits for elderly individuals. Int. J. Environ. Res. Public Health 2019, 16, 4325. [Google Scholar] [CrossRef] [PubMed][Green Version]
  97. Bielinis, E.; Takayama, N.; Boiko, S.; Omelan, A.; Bielinis, L. The effect of winter forest bathing on psychological relaxation of young Polish adults. Urban For. Urban Green. 2018, 29, 276–283. [Google Scholar] [CrossRef]
  98. Iwata, Y.; Dhubháin, A.N.; Brophy, J.; Roddy, D.; Burke, C.; Murphy, B. Benefits of group walking in forests for people with significant mental ill-health. Ecopsychology 2016, 8, 16–26. [Google Scholar] [CrossRef]
  99. Kang, H.; Chae, Y. Effects of integrated indirect forest experience on emotion, fatigue, stress and immune function in hemodialysis patients. Int. J. Environ. Res. Public Health 2021, 18, 1701. [Google Scholar] [CrossRef]
  100. Yi, J.; Kim, S.G.; Khil, T.; Shin, M.; You, J.-H.; Jeon, S.; Park, G.H.; Jeong, A.Y.; Lim, Y.; Kim, J.U. Psycho-electrophysiological benefits of forest therapies focused on qigong and walking with elderly individuals. Int. J. Environ. Res. Public Health 2021, 18, 3004. [Google Scholar] [CrossRef]
  101. Hong, J.; Park, S.; An, M. Are forest healing programs useful in promoting children’s emotional welfare? The Interpersonal relationships of children in foster care. Urban For. Urban Green. 2021, 59, 127034. [Google Scholar] [CrossRef]
  102. Schutte, A.R.; Torquati, J.C.; Beattie, H.L. Impact of urban nature on executive functioning in early and middle childhood. Environ. Behav. 2017, 49, 3–30. [Google Scholar] [CrossRef]
  103. Korpela, K.; Savonen, E.-M.; Anttila, S.; Pasanen, T.; Ratcliffe, E. Enhancing wellbeing with psychological tasks along forest trails. Urban For. Urban Green. 2017, 26, 25–30. [Google Scholar] [CrossRef]
  104. Bielinis, E.; Jaroszewska, A.; Łukowski, A.; Takayama, N. The effects of a forest therapy programme on mental hospital patients with affective and psychotic disorders. Int. J. Environ. Res. Public Health 2020, 17, 118. [Google Scholar] [CrossRef] [PubMed][Green Version]
  105. Sonntag-Öström, E.; Stenlund, T.; Nordin, M.; Lundell, Y.; Ahlgren, C.; Fjellman-Wiklund, A.; Järvholm, L.S.; Dolling, A. “Nature’s effect on my mind”-Patients’ qualitative experiences of a forest-based rehabilitation programme. Urban For. Urban Green. 2015, 14, 607–614. [Google Scholar] [CrossRef][Green Version]
  106. Stigsdotter, U.K.; Corazon, S.S.; Sidenius, U.; Nyed, P.K.; Larsen, H.B.; Fjorback, L.O. Efficacy of nature-based therapy for individuals with stress-related illnesses: Randomised controlled trial. Br. J. Psychiat. 2018, 213, 404–411. [Google Scholar] [CrossRef] [PubMed]
  107. Lee, M.-M.; Lee, D.-G.; Park, B.-J. A needs analysis for the development of forest healing programs: Focusing on cancer patients. J. People Plants Environ. 2020, 23, 683–694. [Google Scholar] [CrossRef]
  108. Jeon, J.Y.; Kim, I.O.; Yeon, P.S.; Shin, W.S. The physio-psychological effect of forest therapy programs on juvenile probationers. Int. J. Environ. Res. Public Health 2021, 18, 5467. [Google Scholar] [CrossRef]
  109. Berger, R. Going on a journey: A case study of nature therapy with children with a learning difficulty. Emot. Behav. Diffic. 2008, 13, 315–326. [Google Scholar] [CrossRef]
  110. Stevenson, M.P.; McEwan, J.; Bentsen, P.; Schilhab, T.; Glue, P.; Trani, P.; Wheeler, B.; Healey, D. Nature walks versus medication: A pre-registered randomized-controlled trial in children with Attention Deficit/Hyperactivity Disorder. J. Environ. Psychol. 2021, 77, 101679. [Google Scholar] [CrossRef]
  111. Han, J.-W.; Choi, H.; Jeon, Y.-H.; Yoon, C.-H.; Woo, J.-M.; Kim, W. The effects of forest therapy on coping with chronic widespread pain: Physiological and psychological differences between participants in a forest therapy program and a control group. Int. J. Environ. Res. Public Health 2016, 13, 255. [Google Scholar] [CrossRef][Green Version]
  112. Zhu, Z.; Zhao, X.; OuYang, Q.; Wang, Y.; Xiong, Y.; Cong, S.; Zhou, M.; Zhang, M.; Luo, X.; Cheng, M. Waterfall forest environment regulates chronic stress via the NOX4/ROS/NF-κB signaling pathway. Front. Neurol. 2021, 12, 619728. [Google Scholar] [CrossRef]
  113. Corazon, S.S.; Sidenius, U.; Vammen, K.S.; Klinker, S.E.; Stigsdotter, U.K.; Poulsen, D.V. The tree is my anchor: A pilot study on the treatment of BED through nature-based therapy. Int. J. Environ. Res. Public Health 2018, 15, 2486. [Google Scholar] [CrossRef]
  114. Ochiai, H.; Song, C.; Jo, H.; Oishi, M.; Imai, M.; Miyazaki, Y. Relaxing effect induced by forest sound in patients with gambling disorder. Sustainability 2020, 12, 5969. [Google Scholar] [CrossRef]
  115. Park, K.-H. Analysis of urban forest healing program expected values, needs, and preferred components in urban forest visitors with diseases: A pilot survey. Int. J. Environ. Res. Public Health 2022, 19, 513. [Google Scholar] [CrossRef] [PubMed]
  116. Choi, J. Perceptions of forest contact and its therapeutic role in university students in South Korea. Amazonia Investiga 2018, 7, 344–350. [Google Scholar]
  117. Jhangiani, R.S.; Chiang, I.-C.A.; Cuttler, C.; Leighton, D.C. Experimental design. In Research Methods in Psychology, 4th ed.; Kwantlen Polytechnic University: Surrey, BC, Canada, 2019; pp. 117–124. [Google Scholar]
  118. Morita, E.; Aoyama, K.; Tamura, T.; Okada, R.; Kawai, S.; Ito, Y.; Naito, M.; Wakai, K.; Hamajima, N. Large-scale survey of frequency of forest walking and related factors in a Japanese population inhabiting a large city, and comparison of an urban area and a rural area. J. For. Res. 2013, 18, 454–461. [Google Scholar] [CrossRef]
  119. Liu, P.; Liu, M.; Xia, T.; Wang, Y.; Wei, H. Can urban forest settings evoke positive emotion? Evidence on facial expressions and detection of driving factors. Sustainability 2021, 13, 8687. [Google Scholar] [CrossRef]
  120. Jo, H.; Ikei, H.; Song, C.; Miyazaki, Y. Individual differences in the psychological effects of forest sounds based on type A and type B behavior patterns. Urban For. Urban Green. 2020, 55, 126855. [Google Scholar] [CrossRef]
  121. Song, C.; Ikei, H.; Park, B.-J.; Lee, J.; Kagawa, T.; Miyazaki, Y. Psychological benefits of walking through forest areas. Int. J. Environ. Res. Public Health 2018, 15, 2804. [Google Scholar] [CrossRef][Green Version]
  122. Mena-García, A.; Olivos, P.; Loureiro, A.; Navarro, O. Effects of contact with nature on connectedness, environmental identity and evoked contents. Psyecology 2020, 11, 21–36. [Google Scholar] [CrossRef]
  123. Rajoo, K.S.; Karam, D.S.; Abdul Aziz, N.A. Developing an effective forest therapy program to manage academic stress in conservative societies: A multi-disciplinary approach. Urban For. Urban Green. 2019, 43, 126353. [Google Scholar] [CrossRef]
  124. Poulsen, D.V.; Stigsdotter, U.K.; Davidsen, A.S. “That guy, is he really sick at all?” An analysis of how veterans with PTSD experience nature-based therapy. Healthcare 2018, 6, 64. [Google Scholar] [CrossRef][Green Version]
  125. Meore, A.; Sun, S.; Byma, L.; Alter, S.; Vitale, A.; Podolak, E.; Gibbard, B.; Adams, T.; Boyer, J.; Haghighi, F. Pilot evaluation of horticultural therapy in improving overall wellness in veterans with history of suicidality. Complement. Ther. Med. 2021, 59, 102728. [Google Scholar] [CrossRef] [PubMed]
  126. Izenstark, D.; Ravindran, N.; Rodriguez, S.; Devine, N. The affective and conversational benefits of a walk in nature among mother–daughter dyads. Appl. Psychol. Health Well-Being 2021, 13, 299–316. [Google Scholar] [CrossRef]
  127. Dahlan, M.Z.; Dewi, M.R.; Putri, V.O. The challenges of forest bathing tourism in Indonesia: A case study in Sudaji Village, Bali. IOP Conf. Ser. Earth Environ. Sci. 2021, 918, 12012. [Google Scholar] [CrossRef]
  128. Ware, S.M. Foraging the future: Forest baths, engaged pedagogy, and planting ourselves into the future. Qual. Inq. 2022, 28, 236–243. [Google Scholar] [CrossRef]
  129. Bratman, G.N.; Daily, G.C.; Levy, B.J.; Gross, J.J. The benefits of nature experience: Improved affect and cognition. Landsc. Urban Plann. 2015, 138, 41–50. [Google Scholar] [CrossRef]
  130. Rajoo, K.S.; Karam, D.S.; Wook, N.-F.; Abdullah, M.-Z. Forest therapy: An environmental approach to managing stress in middle-aged working women. Urban For. Urban Green. 2020, 55, 126853. [Google Scholar] [CrossRef]
  131. Maund, P.R.; Irvine, K.N.; Reeves, J.; Strong, E.; Cromie, R.; Dallimer, M.; Davies, Z.G. Wetlands for wellbeing: Piloting a nature-based health intervention for the management of anxiety and depression. Int. J. Environ. Res. Public Health 2019, 16, 4413. [Google Scholar] [CrossRef] [PubMed][Green Version]
  132. Takayama, N.; Fujiwara, A.; Saito, H.; Horiuchi, M. Management effectiveness of a secondary coniferous forest for landscape appreciation and psychological restoration. Int. J. Environ. Res. Public Health 2017, 14, 800. [Google Scholar] [CrossRef][Green Version]
  133. Sonntag-Öström, E.; Nordin, M.; Järvholm, L.S.; Lundell, Y.; Brännström, R.; Dolling, A. Can the boreal forest be used for rehabilitation and recovery from stress-related exhaustion? A pilot study. Scand. J. For. Res. 2011, 26, 245–256. [Google Scholar] [CrossRef]
  134. Bielinis, E.; Omelan, A.; Boiko, S.; Bielinis, L. The restorative effect of staying in a broad-leaved forest on healthy young adults in winter and spring. Balt. For. 2018, 24, 218–227. [Google Scholar]
  135. Tsunetsugu, Y.; Park, B.-J.; Ishii, H.; Hirano, H.; Kagawa, T.; Miyazaki, Y. Physiological effects of shinrin-yoku (taking in the atmosphere of the forest) in an old-growth broadleaf forest in Yamagata Prefecture, Japan. J. Physiol. Anthropol. 2007, 26, 135–142. [Google Scholar] [CrossRef][Green Version]
  136. Park, B.-J.; Tsunetsugu, Y.; Ishii, H.; Furuhashi, S.; Hirano, H.; Kagawa, T.; Miyazaki, Y. Physiological effects of shinrin-yoku (taking in the atmosphere of the forest) in a mixed forest in Shinano Town, Japan. Scand. J. For. Res. 2008, 23, 278–283. [Google Scholar] [CrossRef]
  137. Yu, C.-P.; Lin, C.-M.; Tsai, M.-J.; Tsai, Y.-C.; Chen, C.-Y. Effects of short forest bathing program on autonomic nervous system activity and mood states in middle-aged and elderly individuals. Int. J. Environ. Res. Public Health 2017, 14, 897. [Google Scholar] [CrossRef] [PubMed][Green Version]
  138. Mihardja, E.J.; Sari, D.A.P.; Widana, I.D.K.K.; Ridhani, C.; Suyasa, I.G.W. Forest bathing: A new attraction and disaster mitigation for Batur. UNESCO Global Geopark Bali. IOP Conf. Ser. Earth Environ. Sci. 2021, 940, 12008. [Google Scholar] [CrossRef]
  139. Droli, M.; Gervasio Radivo, G.; Iseppi, L. Does the establishment of a ‘forest therapy station’ in a low-mountain mixed hardwood forest make sense? Smart Innovat. Sys. Technol. 2021, 178, 67–79. [Google Scholar] [CrossRef]
  140. Lee, H.J.; Son, Y.-H.; Kim, S.; Lee, D.K. Healing experiences of middle-aged women through an urban forest therapy program. Urban For. Urban Green. 2019, 38, 383–391. [Google Scholar] [CrossRef]
  141. Kobayashi, H.; Song, C.; Ikei, H.; Kagawa, T.; Miyazaki, Y. Analysis of individual variations in autonomic responses to urban and forest environments. Evid.-Based Complement. Altern. Med. 2015, 2015, 671094. [Google Scholar] [CrossRef] [PubMed][Green Version]
  142. Marselle, M.R.; Irvine, K.N.; Lorenzo-Arribas, A.; Warber, S.L. Does perceived restorativeness mediate the effects of perceived biodiversity and perceived naturalness on emotional well-being following group walks in nature? J. Environ. Psychol. 2016, 46, 217–232. [Google Scholar] [CrossRef][Green Version]
  143. Alyan, E.; Combe, T.; Rambli, D.R.A.; Sulaiman, S.; Merienne, F.; Diyana, N. The influence of virtual forest walk on physiological and psychological responses. Int. J. Environ. Res. Public Health 2021, 18, 11420. [Google Scholar] [CrossRef] [PubMed]
  144. Crossan, C.; Salmoni, A. A simulated walk in nature: Testing predictions from the attention restoration theory. Environ. Behav. 2021, 53, 277–295. [Google Scholar] [CrossRef][Green Version]
  145. Furuyashiki, A.; Tabuchi, K.; Norikoshi, K.; Kobayashi, T.; Oriyama, S. A comparative study of the physiological and psychological effects of forest bathing (shinrin-yoku) on working age people with and without depressive tendencies. Environ. Health Prev. Med. 2019, 24, 46. [Google Scholar] [CrossRef]
  146. Yamada, A.; Sato, Y.; Horike, T.; Miyanaga, M.; Wang, D.-H. Effects of a forest walk on urinary dityrosine and hexanoyl-lysine in young people: A pilot study. Int. J. Environ. Res. Public Health 2020, 17, 4990. [Google Scholar] [CrossRef]
  147. Lin, W.; Zeng, C.; Bao, Z.; Nie, W.; Nan, X.; Shen, S.; Shi, Y.; Yan, H.; Yang, F.; Wu, R. Study of the vertical structures, thermal comfort, negative air ions, and human physiological stress of forest walking spaces in summer. Forests 2022, 13, 335. [Google Scholar] [CrossRef]
  148. Meneguzzo, F.; Albanese, L.; Antonelli, M.; Baraldi, R.; Becheri, F.R.; Centritto, F.; Donelli, D.; Finelli, F.; Firenzuoli, F.; Neri, L. Short-term effects of forest therapy on mood states: A pilot study. Int. J. Environ. Res. Public Health 2021, 18, 9509. [Google Scholar] [CrossRef]
  149. Lee, K.J.; Hur, J.; Yang, K.-S.; Lee, M.-K.; Lee, S.-J. Acute biophysical responses and psychological effects of different types of forests in patients with metabolic syndrome. Environ. Behav. 2018, 50, 298–323. [Google Scholar] [CrossRef]
  150. Huber, D.; Grafetstätter, C.; Proßegger, J.; Pichler, C.; Wöll, E.; Fischer, M.; Dürl, M.; Geiersperger, K.; Höcketstaller, M.; Hartl, A. Green exercise and mg-ca-SO4 thermal balneotherapy for the treatment of non-specific chronic low back pain: A randomized controlled clinical trial. BMC Musculoskelet. Disord. 2019, 20, 221. [Google Scholar] [CrossRef][Green Version]
  151. Stigsdotter, U.K.; Corazon, S.S.; Sidenius, U.; Kristiansen, J.; Grahn, P. It is not all bad for the grey city—A crossover study on physiological and psychological restoration in a forest and an urban environment. Health Place 2017, 46, 145–154. [Google Scholar] [CrossRef]
  152. Vujcic, M.; Tomicevic-Dubljevic, J.; Grbic, M.; Lecic-Tosevski, D.; Vukovic, O.; Toskovic, O. Nature based solution for improving mental health and well-being in urban areas. Environ. Res. 2017, 158, 385–392. [Google Scholar] [CrossRef]
  153. Zeng, C.; Lyu, B.; Deng, S.; Yu, Y.; Li, N.; Lin, W.; Li, D.; Chen, Q. Benefits of a three-day bamboo forest therapy session on the physiological responses of university students. Int. J. Environ. Res. Public Health 2020, 17, 3238. [Google Scholar] [CrossRef]
  154. Kim, H.; Lee, Y.W.; Ju, H.J.; Jang, B.J.; Kim, Y.I. An exploratory study on the effects of forest therapy on sleep quality in patients with gastrointestinal tract cancers. Int. J. Environ. Res. Public Health 2019, 16, 2449. [Google Scholar] [CrossRef][Green Version]
  155. Corazon, S.S.; Nyed, P.K.; Sidenius, U.; Poulsen, D.V.; Stigsdotter, U.K. A long-term follow-up of the efficacy of nature-based therapy for adults suffering from stress-related illnesses on levels of healthcare consumption and sick-leave absence: A randomized controlled trial. Int. J. Environ. Res. Public Health 2018, 15, 137. [Google Scholar] [CrossRef][Green Version]
  156. Gao, Y.; Zhang, T.; Sasaki, K.; Uehara, M.; Jin, Y.; Qin, L. The spatial cognition of a forest landscape and its relationship with tourist viewing intention in different walking passage stages. Urban For. Urban Green. 2021, 58, 126975. [Google Scholar] [CrossRef]
  157. Morita, E.; Imai, M.; Okawa, M.; Miyaura, T.; Miyazaki, S. A before and after comparison of the effects of forest walking on the sleep of a community-based sample of people with sleep complaints. BioPsychoSoc. Med. 2011, 5, 13. [Google Scholar] [CrossRef][Green Version]
  158. Joung, D.; Lee, B.; Lee, J.; Lee, C.; Koo, S.; Park, C.; Kim, S.; Kagawa, T.; Park, B.-J. Measures to promote rural healthcare tourism with a scientific evidence-based approach. Int. J. Environ. Res. Public Health 2020, 17, 3266. [Google Scholar] [CrossRef]
  159. Sung, J.; Woo, J.-M.; Kim, W.; Lim, S.-K.; Chung, E.-J. The effect of cognitive behavior therapy-based “forest therapy” program on blood pressure, salivary cortisol level, and quality of life in elderly hypertensive patients. Clin. Exp. Hypertens. 2012, 34, 1–7. [Google Scholar] [CrossRef]
  160. Lim, P.Y.; Dillon, D.; Chew, P.K.H. A guide to nature immersion: Psychological and physiological benefits. Int. J. Environ. Res. Public Health 2020, 17, 5989. [Google Scholar] [CrossRef]
  161. Korpela, K.M.; Stengård, E.; Jussila, P. Nature walks as a part of therapeutic intervention for depression. Ecopsychology 2016, 8, 8–15. [Google Scholar] [CrossRef]
  162. Zhu, S.-X.; Hu, F.-F.; He, S.-Y.; Qiu, Q.; Su, Y.; He, Q.; Li, J.-Y. Comprehensive evaluation of healthcare benefits of different forest types: A case study in Shimen National Forest Park, China. Forests 2021, 12, 207. [Google Scholar] [CrossRef]
  163. Morita, E.; Nagano, J.; Yamamoto, H.; Murakawa, I.; Aikawa, M.; Shirakawa, T. Two thirds of forest walkers with Japanese cedar pollinosis visit forests even during the pollen season. Allergol. Int. 2009, 58, 383–388. [Google Scholar] [CrossRef][Green Version]
  164. Guan, H.; Wei, H.; He, X.; Ren, Z.; An, B. The tree-species-specific effect of forest bathing on perceived anxiety alleviation of young-adults in urban forests. Ann. For. Res. 2017, 60, 327–341. [Google Scholar] [CrossRef]
  165. Pratiwi, P.I.; Xiang, Q.; Furuya, K. Physiological and psychological effects of viewing urban parks in different seasons in adults. Int. J. Environ. Res. Public Health 2019, 16, 4279. [Google Scholar] [CrossRef] [PubMed][Green Version]
  166. Lyu, B.; Zeng, C.; Deng, S.; Liu, S.; Jiang, M.; Li, N.; Wei, L.; Yu, Y.; Chen, Q. Bamboo forest therapy contributes to the regulation of psychological responses. J. For. Res. 2019, 24, 61–70. [Google Scholar] [CrossRef]
  167. Conti, E. Tourism Experiences in Forest Areas: An Exploration of Industry Cases; IngoSkog: Stockholm, Sweden, 2019; pp. 1–19. [Google Scholar]
  168. Baroqah, B.; Sudjata, R.G.G.; Irawan, D.J. The benefits of stress relieving treatment in a Healing Forest Program: A pilot project at Ranca Upas, Ciwidey, West Java. IOP Conf. Ser. Earth Environ. Sci. 2021, 918, 12009. [Google Scholar] [CrossRef]
  169. Liu, Q.; Wang, X.; Liu, J.; An, C.; Liu, Y.; Fan, X.; Hu, Y. Physiological and psychological effects of nature experiences in different forests on young people. Forests 2021, 12, 1391. [Google Scholar] [CrossRef]
  170. Marselle, M.R.; Irvine, K.N.; Lorenzo-Arribas, A.; Warber, S.L. Moving beyond green: Exploring the relationship of environment type and indicators of perceived environmental quality on emotional well-being following group walks. Int. J. Environ. Res. Public Health 2015, 12, 106–130. [Google Scholar] [CrossRef]
  171. Zhang, J.; Yang, Z.; Chen, Z.; Guo, M.; Guo, P. Optimizing urban forest landscape for better perceptions of positive emotions. Forests 2021, 12, 1691. [Google Scholar] [CrossRef]
  172. Bielinis, E.; Janeczko, E.; Takayama, N.; Zawadzka, A.; Słupska, A.; Piętka, S.; Lipponen, M.; Bielinis, L. The effects of viewing a winter forest landscape with the ground and trees covered in snow on the psychological relaxation of young Finnish adults: A pilot study. PLoS ONE 2021, 16, e0244799. [Google Scholar] [CrossRef]
  173. Shrestha, T.; Blasi, Z.D.; Cassarino, M. Natural or urban campus walks and vitality in university students: Exploratory qualitative findings from a pilot randomised controlled study. Int. J. Environ. Res. Public Health 2021, 18, 2003. [Google Scholar] [CrossRef]
  174. Kim, J.G.; Khil, T.G.; Lim, Y.; Park, K.; Shin, M.; Shin, W.S. The psychological effects of a campus forest therapy program. Int. J. Environ. Res. Public Health 2020, 17, 3409. [Google Scholar] [CrossRef]
  175. Bielinis, E.; Simkin, J.; Puttonen, P.; Tyrväinen, L. Effect of viewing video representation of the urban environment and forest environment on mood and level of procrastination. Int. J. Environ. Res. Public Health 2020, 17, 5109. [Google Scholar] [CrossRef]
  176. Calogiuri, G.; Litleskare, S.; Fagerheim, K.A.; Rydgren, T.L.; Brambilla, E.; Thurston, M. Experiencing nature through immersive virtual environments: Environmental perceptions, physical engagement, and affective responses during a simulated nature walk. Front. Psychol. 2018, 8, 2321. [Google Scholar] [CrossRef][Green Version]
  177. Mayer, F.S.; Frantz, C.M.; Bruehlman-Senecal, E.; Dolliver, K. Why is nature beneficial? The role of connectedness to nature. Environ. Behav. 2009, 41, 607–643. [Google Scholar] [CrossRef]
  178. Liu, Q.; Wang, X.; Liu, J.; Zhang, G.; An, C.; Liu, Y.; Fan, X.; Hu, Y.; Zhang, H. The relationship between the restorative perception of the environment and the physiological and psychological effects of different types of forests on university students. Int. J. Environ. Res. Public Health 2021, 18, 12224. [Google Scholar] [CrossRef]
  179. Adevi, A.A.; Uvnäs-Moberg, K.; Grahn, P. Therapeutic interventions in a rehabilitation garden may induce temporary extrovert and/or introvert behavioural changes in patients, suffering from stress-related disorders. Urban For. Urban Green. 2018, 30, 182–193. [Google Scholar] [CrossRef]
  180. Janeczko, E.; Bielinis, E.; Wójcik, R.; Woźnicka, M.; Kedziora, W.; Lukowski, A.; Elsadek, M.; Szyc, K.; Janeczko, K. When urban environment is restorative: The effect of walking in suburbs and forests on psychological and physiological relaxation of young polish adults. Forests 2020, 11, 591. [Google Scholar] [CrossRef]
  181. Koselka, E.P.D.; Weidner, L.C.; Minasov, A.; Berman, M.G.; Leonard, W.R.; Santoso, M.V.; de Brito, J.N.; Pope, Z.C.; Pereira, M.A.; Horton, T.H. Walking green: Developing an evidence base for nature prescriptions. Int. J. Environ. Res. Public Health 2019, 16, 4338. [Google Scholar] [CrossRef] [PubMed][Green Version]
  182. Song, C.; Ikei, H.; Kagawa, T.; Miyazaki, Y. Effect of viewing real forest landscapes on brain activity. Sustainability 2020, 12, 6601. [Google Scholar] [CrossRef]
  183. Joung, D.; Kim, G.; Choi, Y.; Lim, H.; Park, S.; Woo, J.-M.; Park, B.-J. The prefrontal cortex activity and psychological effects of viewing forest landscapes in Autumn season. Int. J. Environ. Res. Public Health 2015, 12, 7235–7243. [Google Scholar] [CrossRef][Green Version]
  184. Elsadek, M.; Shao, Y.; Liu, B. Benefits of indirect contact with nature on the physiopsychological well-being of elderly people. Health Environ. Res. Des. J. 2021, 14, 227–241. [Google Scholar] [CrossRef]
  185. Kim, H.; Kim, J.; Ju, H.J.; Jang, B.J.; Wang, T.K.; Kim, Y.I. Effect of forest therapy for menopausal women with insomnia. Int. J. Environ. Res. Public Health 2020, 17, 6548. [Google Scholar] [CrossRef]
  186. Jung, W.H.; Woo, J.-M.; Ryu, J.S. Effect of a forest therapy program and the forest environment on female workers’ stress. Urban For. Urban Green. 2015, 14, 274–281. [Google Scholar] [CrossRef]
  187. Berger, R.; Lahad, M. A safe place: Ways in which nature, play and creativity can help children cope with stress and crisis-establishing the kindergarten as a safe haven where children can develop resiliency. Early Child Dev. Care 2010, 180, 889–900. [Google Scholar] [CrossRef]
  188. Lee, J.-H.; Park, J.-S.; Choi, S. Environmental influence in the forested area toward human health: Incorporating the ecological environment into art psychotherapy. J. Mount. Sci. 2020, 17, 992–1000. [Google Scholar] [CrossRef]
  189. Ramshini, M.; Hassanzadeh, S.; Afrooz, G.; Razini, H.H. The effect of family-centered nature therapy on interactions between parent and child with autism spectrum disorder. Iran. Rehabil. J. 2018, 16, 379–386. [Google Scholar] [CrossRef]
  190. Serrat, M.; Almirall, M.; Musté, M.; Sanabria-Mazo, J.P.; Feliu-Soler, A.; Méndez-Ulrich, J.L.; Luciano, J.V.; Sanz, A. Effectiveness of a multicomponent treatment for fibromyalgia based on pain neuroscience education, exercise therapy, psychological support, and nature exposure (Nat-fm): A pragmatic randomized controlled trial. J. Clinic. Med. 2020, 9, 3348. [Google Scholar] [CrossRef]
  191. Kang, B.-H.; Shin, W.-S. Forest therapy program reduces academic and job-seeking stress among college students. J. People Plants Environ. 2020, 23, 363–375. [Google Scholar] [CrossRef]
  192. Hohashi, N.; Kobayashi, K. The effectiveness of a forest therapy (shinrin-yoku) program for girls aged 12 to 14 years: A crossover study. Stress Sci. Res. 2013, 28, 82–89. [Google Scholar] [CrossRef][Green Version]
  193. Nakau, M.; Imanishi, J.; Imanishi, J.; Watanabe, S.; Imanishi, A.; Baba, T.; Morimoto, Y. Spiritual care of cancer patients by integrated medicine in urban green space: A pilot study. Explore J. Sci. Health 2013, 9, 87–90. [Google Scholar] [CrossRef]
  194. Kim, B.J.; Jeong, H.; Park, S.; Lee, S. Forest adjuvant anti-cancer therapy to enhance natural cytotoxicity in urban women with breast cancer: A preliminary prospective interventional study. Eur. J. Integrat. Med. 2015, 7, 474–478. [Google Scholar] [CrossRef]
  195. Willert, M.V.; Thulstrup, A.M.; Wieclaw, J. Rehabilitation of individuals on long-term sick leave due to sustained stress-related symptoms: A comparative follow-up study. Scand. J. Public Health 2014, 42, 719–727. [Google Scholar] [CrossRef]
  196. Macháčková, K.; Dudík, R.; Zelený, J.; Kolářová, D.; Vinš, Z.; Riedl, M. Forest manners exchange: Forest as a place to remedy risky behaviour of adolescents: Mixed methods approach. Int. J. Environ. Res. Public Health 2021, 18, 5725. [Google Scholar] [CrossRef]
  197. Li, C.; Sun, C.; Sun, M.; Yuan, Y.; Li, P. Effects of brightness levels on stress recovery when viewing a virtual reality forest with simulated natural light. Urban For. Urban Green. 2020, 56, 126865. [Google Scholar] [CrossRef]
  198. Kotera, Y.; Fido, D. Effects of shinrin-yoku retreat on mental health: A pilot study in Fukushima, Japan. Int. J. Mental Health Addict. 2021, 19, 1–13. [Google Scholar] [CrossRef]
  199. Bang, K.-S.; Lee, I.; Kim, S.; Lim, C.S.; Joh, H.-K.; Park, B.-J.; Song, M.K. The effects of a campus forest-walking program on undergraduate and graduate students’ physical and psychological health. Int. J. Environ. Res. Public Health 2017, 14, 728. [Google Scholar] [CrossRef][Green Version]
  200. Sahlin, E.; Ahlborg, G., Jr.; Matuszczyk, J.V.; Grahn, P. Nature-based stress management course for individuals at risk of adverse health effects from work-related stress-effects on stress related symptoms, workability and sick leave. Int. J. Environ. Res. Public Health 2014, 11, 6586–6611. [Google Scholar] [CrossRef] [PubMed][Green Version]
  201. An, B.-Y.; Wang, D.; Liu, X.-J.; Guan, H.-M.; Wei, H.-X.; Ren, Z.-B. The effect of environmental factors in urban forests on blood pressure and heart rate in university students. J. For. Res. 2019, 24, 27–34. [Google Scholar] [CrossRef]
  202. Thomas, T.; Baker, J.; Massey, D.; D’appio, D.; Aggar, C. Stepped-wedge cluster randomised trial of social prescribing of forest therapy for quality of life and biopsychosocial wellbeing in community-living Australian adults with mental illness: Protocol. Int. J. Environ. Res. Public Health 2020, 17, 9076. [Google Scholar] [CrossRef]
  203. Park, B.-J.; Tsunetsugu, Y.; Kasetani, T.; Hirano, H.; Kagawa, T.; Sato, M.; Miyazaki, Y. Physiological effects of shinrin-yoku (taking in the atmosphere of the forest)-Using salivary cortisol and cerebral activity as indicators. J. Physiol. Anthropol. 2007, 26, 123–128. [Google Scholar] [CrossRef] [PubMed][Green Version]
  204. Gao, Y.; Sun, X.M.; Zhang, T.; Zhan, H. Analysis on the characteristics of eye movement and the evaluation of psychological perception for forest waterscape space. IOP Conf. Ser. Earth Environ. Sci. 2021, 626, 12007. [Google Scholar] [CrossRef]
  205. Song, C.; Ikei, H.; Miyazaki, Y. Effects of forest-derived visual, auditory, and combined stimuli. Urban For. Urban Green. 2021, 64, 127253. [Google Scholar] [CrossRef]
  206. Song, C.; Ikei, H.; Park, B.-J.; Lee, J.; Kagawa, T.; Miyazaki, Y. Association between the psychological effects of viewing forest landscapes and trait anxiety level. Int. J. Environ. Res. Public Health 2020, 17, 5479. [Google Scholar] [CrossRef] [PubMed]
  207. Chen, H.-T.; Yu, C.-P.; Lee, H.-Y. The effects of forest bathing on stress recovery: Evidence from middle-aged females of Taiwan. Forests 2018, 8, 403. [Google Scholar] [CrossRef]
  208. Park, B.-J.; Furuya, K.; Kasetani, T.; Takayama, N.; Kagawa, T.; Miyazaki, Y. Relationship between psychological responses and physical environments in forest settings. Landsc. Urban Plann. 2011, 102, 24–32. [Google Scholar] [CrossRef]
  209. Takayama, N.; Korpela, K.; Lee, J.; Morikawa, T.; Tsunetsugu, Y.; Park, B.-J.; Li, Q.; Tyrväinen, L.; Miyazaki, Y.; Kagawa, T. Emotional, restorative and vitalizing effects of forest and urban environments at four sites in Japan. Int. J. Environ. Res. Public Health 2014, 11, 7207–7230. [Google Scholar] [CrossRef][Green Version]
  210. Kobayashi, H.; Ikei, H.; Song, C.; Kagawa, T.; Miyazaki, Y. Comparing the impact of forest walking and forest viewing on psychological states. Urban For. Urban Green. 2021, 57, 126920. [Google Scholar] [CrossRef]
  211. Kobayashi, H.; Song, C.; Ikei, H.; Park, B.-J.; Lee, J.; Kagawa, T.; Miyazaki, Y. Forest walking affects autonomic nervous activity: A population-based study. Front. Public Health 2018, 6, 278. [Google Scholar] [CrossRef][Green Version]
  212. Kobayashi, H.; Song, C.; Ikei, H.; Park, B.-J.; Kagawa, T.; Miyazaki, Y. Combined effect of walking and forest environment on salivary cortisol concentration. Front. Public Health 2019, 7, 376. [Google Scholar] [CrossRef][Green Version]
  213. Fu, D.; Serra, N.I.; Mansion, H.; Mansion, E.T.; Blain-Moraes, S. Assessing the effects of nature on physiological states using wearable technologies. Int. J. Environ. Res. Public Health 2022, 19, 1231. [Google Scholar] [CrossRef]
  214. Igawahara, K.; Kagawa, T.; Takayama, N.; Park, B.-J. Research on the effect which a guide brings about in a forest walk. J. Jpn. Inst. Landsc. Archit. 2015, 70, 597–600. [Google Scholar] [CrossRef][Green Version]
  215. Korcz, N.; Janeczko, E.; Bielinis, E.; Urban, D.; Koba, J.; Szabat, P.; Małecki, M. Influence of informal education in the forest stand redevelopment area on the psychological restoration of working adults. Forests 2021, 12, 993. [Google Scholar] [CrossRef]
  216. Wang, D.-H.; Yamada, A.; Miyanaga, M. Changes in urinary hydrogen peroxide and 8-hydroxy-2′-deoxyguanosine levels after a forest walk: A pilot study. Int. J. Environ. Res. Public Health 2018, 15, 1871. [Google Scholar] [CrossRef] [PubMed][Green Version]
  217. Pálsdóttir, A.M.; Spendrup, S.; Mårtensson, L.; Wendin, K. Garden smellscape–Experiences of plant scents in a nature-based intervention. Front. Psychol. 2021, 12, 667957. [Google Scholar] [CrossRef]
  218. Dickersin, K. Publication bias: Recognizing the problem, understanding its origins and scope, and preventing harm. In Publication Bias in Meta-Analysis—Prevention, Assessment and Adjustments; Rothstein, H.R., Sutton, A.J., Borenstein, M., Eds.; John Wiley & Sons, Ltd.: Chichester, UK, 2005; pp. 11–33. [Google Scholar]
  219. Franco, A.; Malhotra, H.; Simonovits, G. Publication bias in the social sciences: Unlocking the file drawer. Science 2014, 346, 1502–1505. [Google Scholar] [CrossRef]
  220. Soga, M.; Gaston, K.J.; Yamaura, Y. Gardening is beneficial for health: A meta-analysis. Prev. Med. Rep. 2017, 5, 92–99. [Google Scholar] [CrossRef]
  221. Deville, N.V.; Tomasso, L.P.; Stoddard, O.P.; Wilt, G.E.; Horton, T.H.; Wolf, K.L.; Brymer, E.; Kahn, P.H., Jr.; James, P. Time spent in nature is associated with increased pro-environmental attitudes and behaviors. Int. J. Environ. Res. Public Health 2021, 18, 7498. [Google Scholar] [CrossRef]
  222. Mathers, B.; Brymer, E. The power of a profound experience with nature: Living with meaning. Front. Psychol. 2022, 13, 764224. [Google Scholar] [CrossRef]
  223. Van Heezik, Y.; Freeman, C.; Falloon, A.; Buttery, Y.; Heyzer, A. Relationships between childhood experience of nature and green/blue space use, landscape preferences, connection with nature and pro-environmental behavior. Landsc. Urban Plan. 2021, 213, 104135. [Google Scholar] [CrossRef]
  224. Bratton, S.P. Spiritual encounters with nature. Worldviews Environ. Cult. Relig. 2020, 24, 35–57. [Google Scholar] [CrossRef]
  225. Chenoweth, R.E.; Gobster, P.H. The nature and ecology of aesthetic experiences in the landscape. Landsc. J. 1990, 9, 1–8. [Google Scholar] [CrossRef]
  226. Williams, K.; Harvey, D. Transcendent experience in forest environments. J. Environ. Psychol. 2001, 21, 249–260. [Google Scholar] [CrossRef][Green Version]
  227. Clarke, F.J.; Kotera, Y.; McEwan, K. A qualitative study comparing mindfulness and shinrin-yoku (forest bathing): Practitioners’ perspectives. Sustainability 2021, 13, 6761. [Google Scholar] [CrossRef]
  228. Djernis, D.; Lerstrup, I.; Poulsen, D.; Stigsdotter, U.; Dahlgaard, J.; O’Toole, M. A systematic review and meta-analysis of nature-based mindfulness: Effects of moving mindfulness training into an outdoor natural setting. Int. J. Environ. Res. Public Health 2019, 16, 3202. [Google Scholar] [CrossRef]
  229. Lymeus, F.; Lindberg, P.; Hartig, T. Building mindfulness bottom-up: Meditation in natural settings supports open monitoring and attention restoration. Conscious. Cogn. 2018, 59, 40–56. [Google Scholar] [CrossRef]
  230. Shin, W.S. Forest Policy and Forest Healing in the Republic of Korea. Available online: (accessed on 25 July 2022).
  231. Amano, T.; Butt, I.; Peh, K.S.-H. The importance of green spaces to public health: A multi-continental analysis. Ecol. Appl. 2018, 28, 473–1480. [Google Scholar] [CrossRef]
  232. Colléony, A.; White, R.; Shwartz, A. The influence of spending time outside on experience of nature and environmental attitudes. Landsc. Urban Plann. 2019, 187, 96–104. [Google Scholar] [CrossRef]
  233. Mao, G.X.; Cao, Y.B.; Yang, Y.; Chen, Z.M.; Dong, J.H.; Chen, S.S.; Wu, Q.; Lyu, X.Y.; Jia, B.B.; Wang, G.F. Additive benefits of twice forest bathing trips in elderly patients with chronic heart failure. Biomed. Environ. Sci. 2018, 31, 159–162. [Google Scholar] [CrossRef]
  234. Gramkow, M.C.; Sidenius, U.; Zhang, G.; Stigsdotter, U.K. From evidence to design solution—On how to handle evidence in the design process of sustainable, accessible and health-promoting landscapes. Sustainability 2021, 13, 3249. [Google Scholar] [CrossRef]
  235. Cooper Marcus, C. Therapeutic landscapes. In Environmental Psychology and Human Well-Being; Devlin, A.S., Ed.; Academic Press: New York, NY, USA, 2018; pp. 387–413. [Google Scholar] [CrossRef]
  236. Kaplan, R.; Kaplan, S.; Ryan, R.L. With People in Mind: Design and Management of Everyday Nature; Island Press: Covelo, CA, USA, 1998. [Google Scholar]
  237. Storie, M.; Vining, J. From oh to aha: Characteristics and types of environmental epiphany experiences. Hum. Ecol. Rev. 2018, 24, 155–179. [Google Scholar] [CrossRef]
  238. Mundher, R.; Abu Bakar, S.; Maulan, S.; Mohd Yusof, M.J.; Al-Sharaa, A.; Aziz, A.; Gao, H. Aesthetic quality assessment of landscapes as a model for urban forest areas: A systematic literature review. Forests 2022, 13, 991. [Google Scholar] [CrossRef]
  239. Wang, X.; Shi, Y.; Zhang, B.; Chiang, Y. The influence of forest resting environments on stress using virtual reality. Int. J. Environ. Res. Public Health 2019, 16, 3263. [Google Scholar] [CrossRef] [PubMed][Green Version]
  240. Wei, H.; Hauer, R.J.; Guo, S. Daytime dynamic of spontaneous expressions of pedestrians in an urban forest park. Urban For. Urban Green. 2021, 65, 127326. [Google Scholar] [CrossRef]
  241. Lionello, M.; Aletta, F.; Kang, J. A systematic review of prediction models for the experience of urban soundscapes. Appl. Acoust. 2020, 170, 107479. [Google Scholar] [CrossRef]
  242. Hammitt, W.E. Urban forests and parks as privacy refuges. J. Arboric. 2002, 28, 19–26. [Google Scholar] [CrossRef]
  243. Lee, S.; Scott, D. Natural environment influencing people’s affinity for solitude. Urban For. Urban Green. 2017, 21, 235–238. [Google Scholar] [CrossRef]
  244. Ngom, R.; Gosselin, P.; Blais, C. Reduction of disparities in access to green spaces: Their geographic insertion and recreational functions matter. Appl. Geogr. 2016, 66, 35–51. [Google Scholar] [CrossRef]
  245. Rigolon, A. Parks and young people: An environmental justice study of park proximity, acreage, and quality in Denver, Colorado. Landsc. Urban Plann. 2017, 165, 73–83. [Google Scholar] [CrossRef]
  246. Zeller, J.; Doyle, R.; Snodgrass, K. Accessibility Guidebook for Outdoor Recreation and Trails; 1223–2806P–MTDC; U.S. Department of Agriculture, Forest Service, Missoula Technology and Development Center: Missoula, MT, USA, 2012. [Google Scholar]
  247. Stevenson, M.P.; Dewhurst, R.; Schilhab, T.; Bentsen, P. Cognitive restoration in children following exposure to nature: Evidence from the attention network task and mobile eye tracking. Front. Psychol. 2019, 10, 42. [Google Scholar] [CrossRef][Green Version]
  248. Ueda, H.; Takayama, N. A study on the spatial conditions constituting the image of bathing in a forest atmosphere. Landsc. Res. Jpn. Online 2011, 4, 1–6. [Google Scholar] [CrossRef][Green Version]
  249. Zhang, T.; Sasaki, K.; Uehara, M. The distribution of evaluation activities by visitors on walks course of nature recreation forest. Landsc. Res. Jpn. 2013, 6, 6–11. [Google Scholar] [CrossRef]
  250. Arnberger, A.; Eder, R. Are urban visitors’ general preferences for green-spaces similar to their preferences when seeking stress relief? Urban For. Urban Green. 2015, 14, 872–882. [Google Scholar] [CrossRef]
  251. Lohr, V.I.; Pearson-Mims, C.H. Children’s active and passive interactions with plants influence their attitudes and actions toward trees and gardening as adults. HortTechnology 2005, 15, 472–476. [Google Scholar] [CrossRef]
  252. Yu, Y.-M.; Lee, Y.-J.; Kim, J.-Y.; Yoon, S.-B.; Shin, C.-S. Effects of forest therapy camp on quality of life and stress in postmenopausal women. For. Sci. Technol. 2016, 12, 125–129. [Google Scholar] [CrossRef]
  253. Yu, C.-P.S.; Hsieh, H. Beyond restorative benefits: Evaluating the effect of forest therapy on creativity. Urban For. Urban Green. 2020, 51, 126670. [Google Scholar] [CrossRef]
  254. Vujcic Trkulja, M.; Tomicevic-Dubljevic, J.; Tosevski, D.L.; Vukovic, O.; Toskovic, O. Development of evidence-based rehabilitation practice in botanical garden for people with mental health disorders. Health Environ. Res. Des. J. 2021, 14, 242–257. [Google Scholar] [CrossRef] [PubMed]
  255. Zimmerman, H.T.; McClain, L.R. Exploring the outdoors together: Assessing family learning in environmental education. Stud. Educ. Eval. 2014, 41, 38–47. [Google Scholar] [CrossRef]
  256. Clayton, S.; Colléony, A.; Conversy, P.; Maclouf, E.; Martin, L.; Torres, A.-C.; Truong, M.-X.; Prévot, A.-C. Transformation of experience: Toward a new relationship with nature. Cons. Lett. 2017, 10, 645–651. [Google Scholar] [CrossRef][Green Version]
  257. Geist, C.; Galatowitsch, S.M. Reciprocal model for meeting ecological and human needs in restoration projects. Cons. Biol. 1999, 13, 970–979. [Google Scholar] [CrossRef]
  258. Bach, A.; Maneja, R.; Zaldo-Aubanell, Q.; Romanillos, T.; Llusià, J.; Eustaquio, A.; Palacios, O.; Penuelas, J. Human absorption of monoterpenes after a 2-h forest exposure: A field experiment in a Mediterranean holm oak forest. J. Pharm. Biomed. Anal. 2021, 200, 114080. [Google Scholar] [CrossRef]
  259. Bang, K.-S.; Lee, I.-S.; Kim, S.-J.; Song, M.K.; Park, S.-E. The effects of urban forest-walking program on health promotion behavior, physical health, depression, and quality of life: A randomized controlled trial of office-workers. J. Korean Acad. Nurs. 2016, 46, 140–148. [Google Scholar] [CrossRef] [PubMed][Green Version]
  260. Bang, K.-S.; Kim, S.; Song, M.K.; Kang, K.I.; Jeong, Y. The effects of a health promotion program using urban forests and nursing student mentors on the perceived and psychological health of elementary school children in vulnerable populations. Int. J. Environ. Res. Public Health 2018, 15, 1977. [Google Scholar] [CrossRef][Green Version]
  261. Berger, R. Using contact with nature, creativity and rituals as a therapeutic medium with children with learning difficulties: A case study. Emot. Behav. Difficulties 2006, 11, 135–146. [Google Scholar] [CrossRef]
  262. Bielinis, E.; Bielinis, L.; Krupińska-Szeluga, S.; Łukowski, A.; Takayama, N. The effects of a short forest recreation program on physiological and psychological relaxation in young Polish adults. Forests 2019, 10, 34. [Google Scholar] [CrossRef][Green Version]
  263. Bielinis, E.; Lukowski, A.; Omelan, A.; Boiko, S.; Takayama, N.; Grebner, D.L. The effect of recreation in a snow-covered forest environment on the psychological wellbeing of young adults: Randomized controlled study. Forests 2019, 10, 827. [Google Scholar] [CrossRef][Green Version]
  264. Cha, J.; Kim, S. Healing effects of the forest experience on alcoholics. J. Korean Acad. Nurs. 2009, 39, 338–348. [Google Scholar] [CrossRef][Green Version]
  265. Davydenko, M.; Peetz, J. Time grows on trees: The effect of nature settings on time perception. J. Environ. Psychol. 2017, 54, 20–26. [Google Scholar] [CrossRef]
  266. Dolling, A.; Nilsson, H.; Lundell, Y. Stress recovery in forest or handicraft environments—An intervention study. Urban For. Urban Green. 2017, 27, 162–172. [Google Scholar] [CrossRef]
  267. Horiuchi, M.; Endo, J.; Akatsuka, S.; Hasegawa, T.; Yamamoto, E.; Uno, T.; Kikuchi, S. An effective strategy to reduce blood pressure after forest walking in middle-aged and aged people. J. Phys. Ther. Sci. 2015, 27, 3711–3716. [Google Scholar] [CrossRef][Green Version]
  268. Ikei, H.; Song, C.; Kagawa, T.; Miyazaki, Y. Physiological and psychological effects of viewing forest landscapes in a seated position in one-day forest therapy experimental model. Jpn. J. Hyg. 2014, 69, 104–110. [Google Scholar] [CrossRef][Green Version]
  269. Ikei, H.; Koizumi, H.; Song, C.; Kouzuki, M.; Teratani, S.; Sakuma, T.; Miyazaki, Y. Psychological effects of forest therapy program on workers. Jpn. J. Hyg. 2015, 70, 161–166. [Google Scholar] [CrossRef][Green Version]
  270. Jeon, J.Y.; Yeon, P.S.; Shin, W.S. The influence of indirect nature experience on human system. For. Sci. Technol. 2018, 14, 29–32. [Google Scholar] [CrossRef][Green Version]
  271. Jia, B.B.; Yang, Z.X.; Mao, G.X.; Lyu, Y.D.; Wen, X.L.; Xu, W.H.; Lyu, X.L.; Cao, Y.B.; Wang, G.F. Health effect of forest bathing trip on elderly patients with chronic obstructive pulmonary disease. Biomed. Environ. Sci. 2016, 29, 212–218. [Google Scholar] [CrossRef]
  272. Joye, Y.; Bolderdijk, J.W.; Köster, M.A.F.; Piff, P.K. A diminishment of desire: Exposure to nature relative to urban environments dampens materialism. Urban For. Urban Green. 2020, 54, 126783. [Google Scholar] [CrossRef]
  273. Kamitsis, I.; Simmonds, J.G. Using resources of nature in the counselling room: Qualitative research into ecotherapy practice. Int. J. Adv. Counsel. 2017, 39, 229–248. [Google Scholar] [CrossRef]
  274. Kang, H.W.; Lee, G.L. Qualitative content analysis of forest healing experience in forest life. J. People Plants Environ. 2021, 24, 301–309. [Google Scholar] [CrossRef]
  275. Keenan, R.; Lumber, R.; Richardson, M.; Sheffield, D. Three good things in nature: A nature-based positive psychological intervention to improve mood and well-being for depression and anxiety. J. Public Ment. Health 2021, 20, 243–250. [Google Scholar] [CrossRef]
  276. Kim, G.; Park, S.; Kwak, D. Is it possible to predict the concentration of natural volatile organic compounds in forest atmosphere? Int. J. Environ. Res. Public Health 2020, 17, 7875. [Google Scholar] [CrossRef]
  277. Kim, J.-C.; Dinh, T.-V.; Oh, H.-K.; Son, Y.-S.; Ahn, J.-W.; Song, K.-Y.; Choi, I.Y.; Park, C.-R.; Szulejko, J.J.E.; Kim, K.-H. The potential benefits of therapeutic treatment using gaseous terpenes at ambient low levels. Appl. Sci. 2019, 9, 4507. [Google Scholar] [CrossRef][Green Version]
  278. Kim, J.G.; Jeon, J.; Shin, W.S. The influence of forest activities in a university campus forest on student’s psychological effects. Int. J. Environ. Res. Public Health 2021, 18, 2457. [Google Scholar] [CrossRef]
  279. Kiper, T.; Uzun, O.; Topal, T.U. A method approach for identifying thematic footpaths in ecotourism: Kiyikoy pabucdere and Kazandere basins. Fresenius Environ. Bull. 2016, 25, 6139–6150. [Google Scholar]
  280. Lee, J.; Park, B.-J.; Tsunetsugu, Y.; Kagawa, T.; Miyazaki, Y. Physiological benefits of forest environment: Based on field research at 4 sites. Jpn. J. Hyg. 2011, 66, 663–669. [Google Scholar] [CrossRef][Green Version]
  281. Lee, J.; Tsunetsugu, Y.; Takayama, N.; Park, B.-J.; Li, Q.; Song, C.; Komatsu, M.; Ikei, H.; Tyrväinen, L.; Miyazaki, Y. Influence of forest therapy on cardiovascular relaxation in young adults. Evid.-Based Complement. Altern. Med. 2014, 2014, 834360. [Google Scholar] [CrossRef]
  282. Lee, J.-Y.; Lee, D.-C. Cardiac and pulmonary benefits of forest walking versus city walking in elderly women: A randomised, controlled, open-label trial. Eur. J. Integrat. Med. 2014, 6, 5–11. [Google Scholar] [CrossRef]
  283. Li, Q.; Morimoto, K.; Nakadai, A.; Inagaki, H.; Katsumata, M.; Shimizu, T.; Hirata, Y.; Hirata, K.; Suzuki, H.; Kawada, T. Forest bathing enhances human natural killer activity and expression of anti-cancer proteins. Int. J. Immunopathol. Pharmacol. 2007, 20, 3–8. [Google Scholar] [CrossRef]
  284. Li, Q.; Morimoto, K.; Kobayashi, M.; Inagaki, H.; Katsumata, M.; Hirata, Y.; Miyazaki, Y. A forest bathing trip increases human natural killer activity and expression of anti-cancer proteins in female subjects. J. Biol. Regul. Homeost. Agents 2008, 22, 45–55. [Google Scholar]
  285. Li, Q.; Morimoto, K.; Kobayashi, M.; Inagaki, H.; Katsumata, M.; Hirata, Y.; Hirata, K.; Suzuki, H.; Li, Y.J.; Krensky, A.M. Visiting a forest, but not a city, increases human natural killer activity and expression of anti-cancer proteins. Int. J. Immunopathol. Pharmacol. 2008, 21, 117–127. [Google Scholar] [CrossRef] [PubMed]
  286. Li, Q.; Otsuka, T.; Kobayashi, M.; Wakayama, Y.; Inagaki, H.; Katsumata, M.; Hirata, Y.; Li, Y.; Hirata, K.; Kagawa, T. Acute effects of walking in forest environments on cardiovascular and metabolic parameters. Eur. J. Appl. Physiol. 2011, 111, 2845–2853. [Google Scholar] [CrossRef]
  287. Li, Q.; Kobayashi, M.; Kumeda, S.; Ochiai, T.; Miura, T.; Kagawa, T.; Imai, M.; Wang, Z.; Otsuka, T.; Kawada, T. Effects of forest bathing on cardiovascular and metabolic parameters in middle-aged males. J. Evid.-Based Complement. Altern. Med. 2016, 2016, 2587381. [Google Scholar] [CrossRef][Green Version]
  288. Liu, P.; Liu, M.; Xia, T.; Wang, Y.; Guo, P. The relationship between landscape metrics and facial expressions in 18 urban forest parks of Northern China. Forests 2021, 12, 1619. [Google Scholar] [CrossRef]
  289. Mao, G.-X.; Cao, Y.-B.; Lan, X.-G.; He, Z.-H.; Chen, Z.-M.; Wang, Y.-Z.; Hu, H.-L.; Lv, Y.-D.; Wang, G.-F.; Yan, J. Therapeutic effect of forest bathing on human hypertension in the elderly. J. Cardiol. 2012, 60, 495–502. [Google Scholar] [CrossRef] [PubMed][Green Version]
  290. Mao, G.X.; Lan, X.G.; Cao, Y.B.; Chen, Z.M.; He, Z.H.; Lv, Y.D.; Wang, Y.Z.; Hu, H.L.; Wang, G.F.; Yan, J. Effects of short-term forest bathing on human health in a broad-leaved evergreen forest in Zhejiang Province, China. Biomed. Environ. Sci. 2012, 25, 317–324. [Google Scholar] [CrossRef] [PubMed]
  291. Markwell, N.; Gladwin, T.E. Shinrin-yoku (forest bathing) reduces stress and increases people’s positive affect and well-being in comparison with its digital counterpart. Ecopsychology 2020, 12, 247–256. [Google Scholar] [CrossRef]
  292. Marselle, M.R.; Irvine, K.N.; Warber, S.L. Examining group walks in nature and multiple aspects of well-being: A large-scale study. Ecopsychology 2014, 6, 134–147. [Google Scholar] [CrossRef]
  293. Marselle, M.R.; Warber, S.L.; Irvine, K.N. Growing resilience through interaction with nature: Can group walks in nature buffer the effects of stressful life events on mental health? Int. J. Environ. Res. Public Health 2019, 16, 986. [Google Scholar] [CrossRef]
  294. Meneguzzo, F.; Albanese, L.; Bartolini, G.; Zabini, F. Temporal and spatial variability of volatile organic compounds in the forest atmosphere. Int. J. Environ. Res. Public Health 2019, 16, 4915. [Google Scholar] [CrossRef][Green Version]
  295. Morita, E.; Fukuda, S.; Nagano, J.; Hamajima, N.; Yamamoto, H.; Iwai, Y.; Nakashima, T.; Ohira, H.; Shirakawa, T. Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction. Public Health 2007, 121, 54–63. [Google Scholar] [CrossRef][Green Version]
  296. Morita, E.; Naito, M.; Hishida, A.; Wakai, K.; Mori, A.; Asai, Y.; Okada, R.; Kawai, S.; Hamajima, N. No association between the frequency of forest walking and blood pressure levels or the prevalence of hypertension in a cross-sectional study of a Japanese population. Environ. Health Prev. Med. 2011, 16, 299–306. [Google Scholar] [CrossRef][Green Version]
  297. Naor, L.; Mayseless, O. The art of working with nature in nature-based therapies. J. Exp. Educ. 2021, 44, 184–202. [Google Scholar] [CrossRef]
  298. Naor, L.; Mayseless, O. Therapeutic factors in nature-based therapies: Unraveling the therapeutic benefits of integrating nature in psychotherapy. Psychotherapy 2021, 58, 576–590. [Google Scholar] [CrossRef]
  299. Nisbet, E.K.; Zelenski, J.M. Underestimating nearby nature: Affective forecasting errors obscure the happy path to sustainability. Psychol. Sci. 2011, 22, 1101–1106. [Google Scholar] [CrossRef]
  300. Ochiai, H.; Ikei, H.; Song, C.; Kobayashi, M.; Takamatsu, A.; Miura, T.; Miyazaki, Y. Physiological and psychological effects of forest therapy on middle-aged males with high-normal blood pressure. Int. J. Environ. Res. Public Health 2015, 12, 2532–2542. [Google Scholar] [CrossRef] [PubMed][Green Version]
  301. Oh, K.H.; Shin, W.S.; Khil, T.G.; Kim, D.J. Six-step model of nature-based therapy process. Int. J. Environ. Res. Public Health 2020, 17, 685. [Google Scholar] [CrossRef] [PubMed][Green Version]
  302. Ohtsuka, Y.; Yabunaka, N.; Takayama, S. Shinrin-yoku (forest-air bathing and walking) effectively decreases blood glucose levels in diabetic patients. Int. J. Biometeorol. 1998, 41, 125–127. [Google Scholar] [CrossRef] [PubMed]
  303. Ohtsuka, Y.; Yabunaka, N.; Takayama, S. Significance of ‘shinrin-yoku (forest-air bathing and walking)’ as an exercise therapy for elderly patients with diabetes mellitus. J. Jpn. Assoc. Phys. Med. Balneol. Climatol. 1998, 61, 101–105. [Google Scholar]
  304. Park, B.-J.; Tsunetsugu, Y.; Kasetani, T.; Morikawa, T.; Kagawa, T.; Miyazaki, Y. Physiological effects of forest recreation in a young conifer forest in Hinokage Town, Japan. Silva Fenn. 2009, 43, 291–301. [Google Scholar] [CrossRef]
  305. Park, B.-J.; Tsunetsugu, Y.; Morikawa, T.; Kagawa, T.; Lee, J.; Ikei, H.; Song, C.; Miyazaki, Y. Physiological and psychological effects of walking in stay-in forest therapy. Jpn. J. Hyg. 2014, 69, 98–103. [Google Scholar] [CrossRef][Green Version]
  306. Park, B.-J.; Shin, C.-S.; Shin, W.-S.; Chung, C.-Y.; Lee, S.-H.; Kim, D.-J.; Kim, Y.-H.; Park, C.-E. Effects of forest therapy on health promotion among middle-aged women: Focusing on physiological indicators. Int. J. Environ. Res. Public Health 2020, 17, 4348. [Google Scholar] [CrossRef]
  307. Pasanen, T.; Johnson, K.; Lee, K.; Korpela, K. Can nature walks with psychological tasks improve mood, self-reported restoration, and sustained attention? Results from two experimental field studies. Front. Psychol. 2018, 9, 2057. [Google Scholar] [CrossRef][Green Version]
  308. Pratiwi, P.I.; Xiang, Q.; Furuya, K. Physiological and psychological effects of walking in urban parks and its imagery in different seasons in middle-aged and older adults: Evidence from Matsudo City, Japan. Sustainability 2020, 12, 4003. [Google Scholar] [CrossRef]
  309. Roviello, V.; Roviello, G.N. Less COVID-19 deaths in southern and insular Italy explained by forest bathing, Mediterranean environment, and antiviral plant volatile organic compounds. Environ. Chem. Lett. 2021, 20, 7–17. [Google Scholar] [CrossRef]
  310. Rozmi, M.D.A.; Rambli, D.R.A.; Sulaiman, S.; Zamin, N.; Muhaiyuddin, N.D.M.; Mean, F.O. Design considerations for a virtual reality-based nature therapy to release stress. In Proceedings of the 2019 International Conference on Advances in the Emerging Computing Technologies (AECT), Al Madinah Al Munawwarah, Saudi Arabia, 10 February 2020; p. 9194175. [Google Scholar] [CrossRef]
  311. Saito, H.; Horiuchi, M.; Takayama, N.; Fujiwara, A. Effects of managed forest versus unmanaged forest on physiological restoration from a stress stimulus, and the relationship with individual traits. J. For. Res. 2019, 24, 77–85. [Google Scholar] [CrossRef]
  312. Shin, W.S.; Shin, C.S.; Yeoun, P.S. The influence of forest therapy camp on depression in alcoholics. Environ. Health Prev. Med. 2012, 17, 73–76. [Google Scholar] [CrossRef] [PubMed][Green Version]
  313. Sidenius, U.; Nyed, P.K.; Stigsdotter, U.K. A new approach to nature consumption post nature-based therapy. Alam Cipta 2020, 13, 48–56. [Google Scholar]
  314. Song, C.; Ikei, H.; Lee, J.; Park, B.-J.; Kagawa, T.; Miyazaki, Y. Individual differences in the physiological effects of forest therapy based on Type A and Type B behavior patterns. J. Physiol. Anthropol. 2013, 32, 14. [Google Scholar] [CrossRef][Green Version]
  315. Song, C.; Joung, D.; Ikei, H.; Igarashi, M.; Aga, M.; Park, B.-J.; Miwa, M.; Takagaki, M.; Miyazaki, Y. Physiological and psychological effects of walking on young males in urban parks in winter. J. Physiol. Anthropol. 2013, 32, 18. [Google Scholar] [CrossRef]
  316. Song, C.; Ikei, H.; Miyazaki, Y. Elucidation of the physiological adjustment effect of forest therapy. Jpn. J. Hyg. 2014, 69, 111–116. [Google Scholar] [CrossRef][Green Version]
  317. Song, C.; Ikei, H.; Kagawa, T.; Miyazaki, Y. Elucidation of individual differences in the psychological effects of a forest environment. In Psychology of Individual Differences: New Research; Roberson, E., Ed.; Nova Science Publishers: New York, NY, USA, 2016; pp. 47–68. [Google Scholar]
  318. Song, C.; Ikei, H.; Miyazaki, Y. Physiological effects of visual stimulation with forest imagery Int. J. Environ. Res. Public Health 2018, 15, 213. [Google Scholar] [CrossRef][Green Version]
  319. Song, C.; Ikei, H.; Kagawa, T.; Miyazaki, Y. Effects of walking in a forest on young women. Int. J. Environ. Res. Public Health 2019, 16, 229. [Google Scholar] [CrossRef][Green Version]
  320. Song, C.; Ikei, H.; Kagawa, T.; Miyazaki, Y. Physiological and psychological effects of viewing forests on young women. Forests 2019, 10, 635. [Google Scholar] [CrossRef][Green Version]
  321. Song, C.; Ikei, H.; Miyazaki, Y. Physiological effects of forest-related visual, olfactory, and combined stimuli on humans: An additive combined effect. Urban For. Urban Green. 2019, 44, 126437. [Google Scholar] [CrossRef]
  322. Sonntag-Öström, E.; Nordin, M.; Lundell, Y.; Dolling, A.; Wiklund, U.; Karlsson, M.; Carlberg, B.; Slunga Järvholm, L. Restorative effects of visits to urban and forest environments in patients with exhaustion disorder. Urban For. Urban Green. 2014, 13, 344–354. [Google Scholar] [CrossRef]
  323. Sonntag-Öström, E.; Nordin, M.; Dolling, A.; Lundell, Y.; Nilsson, L.; Slunga Järvholm, L. Can rehabilitation in boreal forests help recovery from exhaustion disorder? The randomised clinical trial ForRest. Scand. J. For. Res. 2015, 30, 732–748. [Google Scholar] [CrossRef]
  324. Takayama, N.; Saito, H.; Fujiwara, A.; Horiuchi, M. The effect of slight thinning of managed coniferous forest on landscape appreciation and psychological restoration. Progr. Earth Planet. Sci. 2017, 4, 17. [Google Scholar] [CrossRef][Green Version]
  325. Takayama, N.; Morikawa, T.; Bielinis, E. Relation between psychological restorativeness and lifestyle, quality of life, resilience, and stress-coping in forest settings. Int. J. Environ. Res. Public Health 2019, 16, 1456. [Google Scholar] [CrossRef][Green Version]
  326. Takayama, N.; Morikawa, T.; Koga, K.; Miyazaki, Y.; Harada, K.; Fukumoto, K.; Tsujiki, Y. Exploring the physiological and psychological effects of digital shinrin-yoku and its characteristics as a restorative environment. Int. J. Environ. Res. Public Health 2022, 19, 1202. [Google Scholar] [CrossRef]
  327. Varning Poulsen, D.; Lygum, V.L.; Djernis, H.G.; Stigsdotter, U.K. Nature is just around us! Development of an educational program for implementation of nature-based activities at a crisis shelter for women and children exposed to domestic violence. J. Soc. Work Pract. 2021, 35, 159–175. [Google Scholar] [CrossRef]
  328. Wang, C.; Bai, Y.; Tian, M. Ecological research on China forest therapy purchasing behavior based on SEM. Ekoloji 2019, 28, 955–964. [Google Scholar]
  329. Wei, H.; Hauer, R.J.; Chen, X.; He, X. Facial expressions of visitors in forests along the urbanization gradient: What can we learn from selfies on social networking services? Forests 2019, 10, 1049. [Google Scholar] [CrossRef][Green Version]
  330. White, P.C.L.; Wyatt, J.; Chalfont, G.; Bland, J.M.; Neale, C.; Trepel, D.; Graham, H. Exposure to nature gardens has time-dependent associations with mood improvements for people with mid- and late-stage dementia: Innovative practice. Dementia 2018, 17, 627–634. [Google Scholar] [CrossRef]
  331. Wu, Q.; Ye, B.; Chen, Z.M.; Lyu, X.L.; Ren, X.X.; Dong, J.H.; Wang, G.F. Medical assessment on forest therapy base in Zhejiang Province, China. Biomed. Environ. Sci. 2019, 32, 934–937. [Google Scholar] [CrossRef]
  332. Yamada, A.; Wang, D.H.; Miyanaga, M. Assessment of Psychophysiological Effects of Forest and Urban Walking on Young People. Naturalistae 2020, 24, 1–5. Available online: (accessed on 25 July 2022).
  333. Yamaguchi, M.; Deguchi, M.; Miyazaki, Y. The effects of exercise in forest and urban environments on sympathetic nervous activity of normal young adults. J. Int. Med. Res. 2006, 34, 152–159. [Google Scholar] [CrossRef]
  334. Zhou, C.; Yan, L.; Yu, L.; Wei, H.; Guan, H.; Shang, C.; Chen, F.; Bao, J. Effect of short-term forest bathing in urban parks on perceived anxiety of young-adults: A pilot study in Guiyang, Southwest China. Chin. Geogr. Sci. 2019, 29, 139–150. [Google Scholar] [CrossRef]
Figure 1. Forest therapy interaction process.
Figure 1. Forest therapy interaction process.
Forests 13 01613 g001
Figure 2. Forest therapy publication trends 2006–2021, top 6 countries (67% all articles).
Figure 2. Forest therapy publication trends 2006–2021, top 6 countries (67% all articles).
Forests 13 01613 g002
Table 1. Concepts measured by psychological and physiological indicators in the article set.
Table 1. Concepts measured by psychological and physiological indicators in the article set.
Conceptsn ArticlesPercent
Psychological Concepts (n = 219 Articles)
General well-being3917.8
Perceived restoration3214.6
Environmental perception-preference2511.4
Qualitative (e.g., open-ended)2310.5
Cognitive function219.6
General health/lifestyle177.8
Nature connectedness146.4
Physical activity (self-report)94.1
Social connectedness73.2
Physiological Concepts (n = 135 articles)
Physical health and mobility128.9
Cognitive function107.4
Miscellaneous other2115.6
Table 2. Statistical summary of participant sample characteristics (n = 252 articles reporting).
Table 2. Statistical summary of participant sample characteristics (n = 252 articles reporting).
Sample Population StatisticsMMdnModeSDSkewnessMinMax
Number of participants259.338.512918.0126.1618792
Percent female0.510.5300.323−0.21101.00
Average age36.7352217.8060.434583
Table 3. Statistical summary of site and trail characteristics for the article set.
Table 3. Statistical summary of site and trail characteristics for the article set.
Characteristics *MMdnModeSDSkewnessMinMax
Site Characteristics
Number of Sites3.4118.585157
Smallest site (ha)29072221.494905.220.2565,650
Largest site (ha)48513251.416,9244.960.25103,848
Trail Characteristics
Shortest trail (km)2.5211.630.820.27
Longest trail (km)3.92.923.633.310.623
Average trail (km)32.521.921.480.611
* n = 219 articles reporting number of sites, n = 67 reporting site size, n = 57 articles reporting trail characteristics.
Table 4. Notable features mentioned in forest setting descriptions in the article set (n = 134 articles reporting).
Table 4. Notable features mentioned in forest setting descriptions in the article set (n = 134 articles reporting).
FeaturenPercentExample Citations
Water features3727.6[148,149,150]
Rich, diverse tree/plant species3425.4[131,151,152]
Designated, protected area2720.1[12,82,153]
Wild, natural, unmanaged2518.7[84,154,155]
Large, old growth trees1914.2[80,104,156]
Scenic, special views1712.7[111,130,153]
Extravisual sounds, smells, atmospheric (e.g., VOCs)1611.9[35,143,151]
Diverse trail opportunities1611.9[123,158,159]
Tended, garden107.5[34,81,98]
Built support features107.5[58,160,161]
Unique features86.0[110,164,165]
Table 5. Relevant themes and subthemes of key features and characteristics extracted from a lexicometric analysis of forest setting descriptions in the article set.
Table 5. Relevant themes and subthemes of key features and characteristics extracted from a lexicometric analysis of forest setting descriptions in the article set.
Themes and Subthemesn TermsTotal OccurrencesPercent of Occurrences
Natural landscape features and characteristics
(62 terms, 771 total occurrences)
Cultural landscape features and characteristics
(56 terms, 414 occurrences)
Support facilities116315.2
Misc. other development145613.5
Evaluative characteristics and qualities
(60 terms, 575 occurrences)
Viewscape characteristics
(36 terms, 290 occurrences)
Table 6. Forest outcome comparisons made by studies in the article set.
Table 6. Forest outcome comparisons made by studies in the article set.
Comparison Subcategoriesn ArticlesPercent of All Studies *Percent of Subcategory Comparisons
Significant DifferencesNon-Significant or Mixed DifferencesResults Too Complex to Code
No comparisons10038.3NANANA
Forest vs. urban7729.588.012.00.0
Forest vs. control3111.974.026.00.0
Within-forest comparisons5019.
Virtual comparisons197.368.426.35.3
* Percentages do not sum to zero because some studies made multiple comparisons (e.g., forest vs. urban and within-forest comparisons).
Table 7. Major engagement activity and other specific activities engaged in by forest therapy participants (n = 230 articles reporting).
Table 7. Major engagement activity and other specific activities engaged in by forest therapy participants (n = 230 articles reporting).
Engagement Activityn ArticlesPercentExample Citations
Basic Activities
Stationary viewing7532.6[182,183,184]
Other activities10445.2[76,77,80]
Specific Other Activities
Relaxation and relaxation/non-aerobic exercises5423.5[90,91,152]
Five sense exercises, “invitations,”, etc.4820.9[80,174,185]
Meditation, sitting-contemplating4117.8[78,108,186]
Conversation, group time, sharing, etc.3013.0[34,187,188]
Purposeful hands-on engagement with nature219.1[12,68,189]
Arts and crafts activities, photography219.1[190,191,192]
Aerobic exercises, e.g., calisthenics, folk dancing177.4[36,82,100]
Games, forest orienteering, geocaching167.0[101,149,174]
Eating and drinking, incl forest products167.0[48,167,189]
General counseling, psychotherapy, CBT125.2[106,159,193]
Free time, unstructured time125.2[34,46,194]
Mindfulness info, forest therapy lectures104.3[125,190,195]
Environmental info about site or more general93.9[131,196,197]
Other outdoor recreational activities93.9[46,68,198]
Physical or general health info83.5[195,199,200]
Other, vague or unspecified52.2[73,201,202]
Table 8. Summary characteristics of interactions for different research activity types.
Table 8. Summary characteristics of interactions for different research activity types.
Forest bathing
(n = 109 articles, n = 59–66 reporting)
Length of intervention (h)1.330.750.251.2700.9750.175
Number of sessions1.44112.0286.662116
Total length of intervention (h)2.390.750.254.8544.6100.1732
Maximum group size8.73619.4191.561144
Tl. “other” engagement activities0.61001.1082.10405
Forest/nature/park walks
(n = 76 articles, n = 33–52 reporting)
Length of intervention (h)1.230.8821.0311.5280.235
Number of sessions2.61112.7371.378110
Total length of intervention (h)3.671.50.255.5552.3150.2325
Maximum group size5.88216.3091.360126
Tl. “other” engagement activities0.54001.1632.31705
Forest/nature/park therapy
(n = 109, n = 71–89 reporting)
Length of intervention (h)2.82321.9220.2670.026
Number of sessions9.606112.7272.831180
Total length of intervention (h)29.03121254.4905.5380.02440
Maximum group size11.83919.3870.628133
Tl. “other” engagement activities2.80302.079−0.07307
Virtual studies
(n = 17, n = 16–17 reporting)
Length of intervention (h)
Number of sessions1.25111.0004.00015
Total length of intervention (h)
Maximum group size1.24110.9704.12315
Tl. “other” engagement activities0.00000.000-00
All research activity types
(n = 266, n = 183–230 reporting)
Length of intervention (h)1.861.500.251.7590.9190.026
Number of sessions5.02119.1374.287180
Total length of intervention (h)13.4620.2537.1918.0450.02440
Maximum group size8.68618.9491.245144
Tl. “other” engagement activities1.43001.9131.03407
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Gobster, P.H.; Schultz, C.L.; Kruger, L.E.; Henderson, J.R. Forest Therapy Trails: A Conceptual Framework and Scoping Review of Research. Forests 2022, 13, 1613.

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Gobster PH, Schultz CL, Kruger LE, Henderson JR. Forest Therapy Trails: A Conceptual Framework and Scoping Review of Research. Forests. 2022; 13(10):1613.

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Gobster, Paul H., Courtney L. Schultz, Linda E. Kruger, and John R. Henderson. 2022. "Forest Therapy Trails: A Conceptual Framework and Scoping Review of Research" Forests 13, no. 10: 1613.

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