Table 3.

Interdisciplinary research (n = 3)

Authors (year)	Research design	Participants		Intervention measures	Control measures	Measurements			Outcomes
		Trial group	Control group			Self-report measures	Physiological measures	Forest inventory
Takayama (2017) [44]	NRCT (cross-over study)※	1) Male and female participants, the average age was 40.2 years (n = 9). 2) Sparse forest environment	1) Male and female participants, the average age was 40.2 years (n = 9). 2) Dense forest environment	The trial group was exposed to a sparse forest environment and sat quietly for 15 min, while the control group was exposed to a dense forest environment and sat quietly for 15 min, and then the two groups exchanged environments	1) The trial began in the summer. 2) The trial lasted for 4 days. 3) Alcohol was banned 24 h before the trial and caffeine was banned 12 h before the trial. 4) All subjects did not have a history of cardiovascular disease and psychosis, and did not take medications that could affect their psychology. 5) The interval between the trial in different environments was 10 min	Positive and Negative Affect Schedule: Positive↑ Negative *↓ POMS: D#*↓ V↑ T-A↓ F↓ C↓ A-H↓ Perceived Restorativeness Scale: Compatibility scores#↑ Restorative Outcome Scale scores↑	N/A	Stand density Stand basal area Species composition Forest photos Hemispherical photograph Forest micrometeorology	Temperature↑ Relative humidity #↑ Wind velocity#↓ Radiant heat↑ Illuminance#↑ Sound pressure#↑	1) Both sparse forest and dense forest had recovery effect on the participants, but the participants evaluated the sparse forest environment more positively. 2) Strengthening forest structure management can improve the healing effect of forest environment on human body
Guan (2017) [45]	RCT	1) Male and female participants, the average age was 22 years (n = 20). The environment is birch forest (Betulaplatyphylla Suk). 2) Male and female participants, the average age was 21.6 years (n = 23). The environment is maple forest (Acer triflorum) 3) Male and female participants, the average age was 21.6 years (n = 26). The environment is oak forest (Quercus mongolica)		The participants were exposed to the forest environment, first taking a tree-measuring course for 20 min, and then enjoying 40 min of private time	1) The trial began in the spring. 2) All participants had no history of cardiovascular disease, allergic symptoms, or mental illness. 3) High-intensity activities, smoking and drinking were prohibited during the trial	Homemade scales: Anxiety caused by employment pressure (birch forest)*↓ Anxiety caused by study interest (maple forest)*↓ Anxiety caused by lesion satisfaction (oak forest)#↓	N/A	Height of tree Diameter at breast height Canopy length Canopy cover rate Density	1) The correlation of weight, age and anti-anxiety score was the highest. 2) Forest bathing can promote college students' interest in learning. 3) Overweight young people were better at reducing anxiety. 4) Female participants in the oak forest showed higher levels of anxiety relief than male
Zhou (2019) [46]	RCT (cross-over study)	Male and female participants, age range 19–23 years (n = 24)	Male and female participants, age range 19–23 years (n = 19)	Day 1, the trial group was exposed to urban forest park, while the control group was exposed to suburban forest parks. Day 2, the two groups interchanged environments	1) The trial began in the winter. 2) The trial lasted for 2 days	Homemade scales (anti-anxiety score): Finance state*↑ Exam-pass pressure*#↓ Campus life*#↓ Love affair relationship*↑	N/A	Canopy density Diameter at breast height Plant species	1) The forest richness of suburban forest park is higher than that of urban forest park. 2) Suburban forest park can alleviate interpersonal anxiety in participants more than urban forest parks

*Significant intra-group differences

^#Significant inter-group differences

n, sample size; “↑”, indicators rise; “↓”, Indicators decline; N/A, no report; “※”, has passed ethical review; A-H, anger and hostility; C, confusion; D, depression; F, fatigue; NRCT, non-randomized controlled trial; POMS, profile of mood states; RCT, randomized controlled trial; T-A, tension and anxiety; V, vigor