This study is to analyze the forest healing effects of users according to forest types and users’ stay durations in forests. Forest types are classified into Chamaecyparis obtusa, Quercus serrata and Pinus densiflora and the subjects of this study, 64 hypertensives, 59 diabetics and 59 ordinary people, have been tested to see their physiological and psychological effects. The index of physiological reaction comprises electroencephalogram(EEG), heart rate variability(HRV), blood pressure, pulse and cortisol. The index of psychological one includes the profile of moods states(POMS) and perceived healing evaluation. The images of forests and users’ preferences on those are evaluated by a Likert scale. The result of this study is as follows:
1. An analysis on the stress buffering effect from the physiological reactions of the overall subjects indicates that Quercus serrata forest has higher stress buffering effect than others in terms of central nervous, endocrine and autonomic nervous systems. Chamaecyparis obtusa forest is contributory in soothing stress in central nervous and endocrine systems. Pinus densiflora forest is contributing in some index of endocrine and autonomic nervous systems. Regarding the stress buffering effect by forest types, Chamaecyparis obtusa forest is effective for a central nervous system and Quercus serrata forest for endocrine and autonomic systems. In contrast, Pinus densiflora forest is less influential to a stress buffering effect than the other two.
2. With regard to blood pressure decline in the effect frequency over hypertensives, the high chance of forest healing is expected now that the frequency of blood pressure decline is high in every forest. In the degree of the antihypertensive effect, Chamaecyparis obtusa and Quercus serrata forests are more effective than Pinus densiflora forest. Therefore, staying in the first two forests can heighten the antihypertensive effect on hypertensives. Forest types make no difference in stress buffering effect.
3. Every forest is efficacious to diabetics’ hypoglycaemic action. Particularly, staying in Quercus serrata forest is more effective in hypoglycemic as well as stress buffering effects.
4. A scrutiny on the physiological reactions from the ordinary people indicates that the frequency of stress buffering effect is high in every forest. In view of the degree of the effect, Chamaecyparis obtusa forest makes the dramatic change in soothing stress. Accordingly, for the ordinary people, staying in the forest can lead to the most effective impact in buffering stress.
5. Regarding the physiological change of the overall subjects according to the stay duration based on forest types, 90 minute stay in Chamaecyparis obtusa forest, which is relevant to EEG, HRV and blood pressure, and 3 hour stay in the forest, relevant to pulse and cortisol, can create stress-soothing effect. In Quercus serrata forest, 3 hour stay highly soothes stress with changing EEG, HRV, pulse and cortisol. In Pinus densiflora forest, 90 minute stay guarantees high stress buffering effect in EEG, HRV and blood pressure and 3 hour stay does in pulse and cortisol.
6. An analysis on healing effect by stay duration shows that hypertensives see stronger antihypertensive effect when they stay in every forest for 3 hours instead of 90 minutes. For diabetics, 3 hour stay in every forest obtains more hypoglycemic effect than 90 minute stay.
7. Regarding stress buffering effect according to stay duration in the ordinary people’s physiological dimension, 3 hours stay in Chamaecyparis obtusa forest and 90 minutes or 3 hours in Quercus serrata and Pinus densiflora forests yield effective consequence in decreasing stress.
8. The perceived images on each forest are that Chamaecyparis obtusa is comfortable and intimidate, Quercus serrata is general, stable and open, and Pinus densiflora is beautiful, pleasant and natural.
9. The structure of forest images are categorized into factors, such as orderliness, amenity, singularity and emotion, which has the 58.4% of total variance. In the structure and satisfaction to each forest, orderliness is remarkable in Chamaecyparis obtusa forest, orderliness and singularity in Quercus serrata forest and amenity in Pinus densiflora forest.
10. Following all subjects’ staying in three types of forests, their emotional conditions are improved in psychological stability. Chamaecyparis obtusa and Pinus densiflora forests are particularly helpful for ameliorating the mood states. With regard to a subcategory, Chamaecyparis obtusa forest improves the condition in the fields of tension, confusion and vigor, Quercus serrata forest does in tension and Pinus densiflora forest does in tension, depression, fatigue, confusion and vigor.
11. After staying in every forest, all subjects perceive the healing effect to improve physical and emotional dimensions. The perception of healing is high in the order of Pinus densiflora, Quercus serrata and Chamaecyparis obtusa forests.
12. Forest types and disease types do not demonstrate any correlation between the POMS for psychological reaction and physiological reaction. There is also no relation between subjective perceived healing evaluation and physiological reaction.